All Implemented Interfaces:

android.content.SharedPreferences , android.content.SharedPreferences.Editor
```
public class MMKV
 implements SharedPreferences, SharedPreferences.Editor
                    
```
An highly efficient, reliable, multi-process key-value storage framework. THE PERFECT drop-in replacement for SharedPreferences and MultiProcessSharedPreferences.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`public interface`	`MMKV.LibLoader`	The interface for providing a 3rd library loader (the ReLinker https://github.com/KeepSafe/ReLinker, etc).

Field Summary

Fields
Modifier and Type	Field	Description
`private static String`	`rootDir`
`public final static int`	`SINGLE_PROCESS_MODE`
`public final static int`	`MULTI_PROCESS_MODE`
`public final static int`	`READ_ONLY_MODE`
`public final static int`	`ExpireNever`
`public final static int`	`ExpireInMinute`
`public final static int`	`ExpireInHour`
`public final static int`	`ExpireInDay`
`public final static int`	`ExpireInMonth`
`public final static int`	`ExpireInYear`

Method Summary

Modifier and Type	Method	Description
`static String`	`getRootDir()`
`static String`	`initialize(@NonNull() Context context)`	Initialize MMKV with default configuration.You must call one of the initialize() methods on App startup process before using MMKV.
`static String`	`initialize(@NonNull() Context context, MMKVLogLevel logLevel)`	Initialize MMKV with customize log level.You must call one of the initialize() methods on App startup process before using MMKV.
`static String`	`initialize(@NonNull() Context context, MMKV.LibLoader loader)`	Initialize MMKV with a 3rd library loader.You must call one of the initialize() methods on App startup process before using MMKV.
`static String`	`initialize(@NonNull() Context context, MMKV.LibLoader loader, MMKVLogLevel logLevel)`	Initialize MMKV with a 3rd library loader, and customize log level.You must call one of the initialize() methods on App startup process before using MMKV.
`static String`	`initialize(Context context, String rootDir)`	Initialize MMKV with customize root folder.You must call one of the initialize() methods on App startup process before using MMKV.
`static String`	`initialize(Context context, String rootDir, MMKVLogLevel logLevel)`	Initialize MMKV with customize root folder, and log level.You must call one of the initialize() methods on App startup process before using MMKV.
`static String`	`initialize(Context context, String rootDir, MMKV.LibLoader loader)`	Initialize MMKV with customize root folder, and a 3rd library loader.You must call one of the initialize() methods on App startup process before using MMKV.
`static String`	`initialize(Context context, String rootDir, MMKV.LibLoader loader, MMKVLogLevel logLevel)`	Initialize MMKV with customize settings.You must call one of the initialize() methods on App startup process before using MMKV.
`static String`	`initialize(@NonNull() Context context, String rootDir, MMKV.LibLoader loader, MMKVLogLevel logLevel, MMKVHandler handler)`
`static String`	`initialize(String rootDir)`
`static String`	`initialize(String rootDir, MMKVLogLevel logLevel)`
`static String`	`initialize(String rootDir, MMKV.LibLoader loader)`
`static String`	`initialize(String rootDir, MMKV.LibLoader loader, MMKVLogLevel logLevel)`
`static NameSpace`	`nameSpace(String dir)`
`static NameSpace`	`defaultNameSpace()`	identical with the original MMKV with the global root dir
`static void`	`setLogLevel(MMKVLogLevel level)`	Set the log level of MMKV.
`static native void`	`onExit()`	Notify MMKV that App is about to exit.
`static MMKV`	`mmkvWithID(String mmapID)`	Create an MMKV instance with an unique ID (in single-process mode).
`static MMKV`	`mmkvWithID(String mmapID, int mode)`	Create an MMKV instance in single-process or multi-process mode.
`static MMKV`	`mmkvWithID(String mmapID, int mode, long expectedCapacity)`	Create an MMKV instance in single-process or multi-process mode.
`static MMKV`	`mmkvWithID(String mmapID, int mode, @Nullable() String cryptKey)`	Create an MMKV instance in customize process mode, with an encryption key.
`static MMKV`	`mmkvWithID(String mmapID, String rootPath)`	Create an MMKV instance in customize folder.
`static MMKV`	`mmkvWithID(String mmapID, String rootPath, long expectedCapacity)`	Create an MMKV instance in customize folder.
`static MMKV`	`mmkvWithID(String mmapID, int mode, @Nullable() String cryptKey, String rootPath, long expectedCapacity)`	Create an MMKV instance with customize settings all in one.
`static MMKV`	`mmkvWithID(String mmapID, int mode, @Nullable() String cryptKey, String rootPath)`	Create an MMKV instance with customize settings all in one.
`static MMKV`	`backedUpMMKVWithID(String mmapID, int mode, @Nullable() String cryptKey, String rootPath)`	Get an backed-up MMKV instance with customize settings all in one.
`static MMKV`	`mmkvWithAshmemID(Context context, String mmapID, int size, int mode, @Nullable() String cryptKey)`	Create an MMKV instance base on Anonymous Shared Memory, aka not synced to any disk files.
`static MMKV`	`defaultMMKV()`	Create the default MMKV instance in single-process mode.
`static MMKV`	`defaultMMKV(int mode, @Nullable() String cryptKey)`	Create the default MMKV instance in customize process mode, with an encryption key.
`static void`	`enableProcessModeChecker()`	Manually enable the process mode checker.By default, it's automatically enabled in DEBUG build, and disabled in RELEASE build.If it's enabled, MMKV will throw exceptions when an MMKV instance is created with mismatch process mode.
`static void`	`disableProcessModeChecker()`	Manually disable the process mode checker.By default, it's automatically enabled in DEBUG build, and disabled in RELEASE build.If it's enabled, MMKV will throw exceptions when an MMKV instance is created with mismatch process mode.
`native String`	`cryptKey()`
`native boolean`	`reKey(@Nullable() String cryptKey)`	Transform plain text into encrypted text, or vice versa by passing a null encryption key.You can also change existing crypt key with a different cryptKey.
`native void`	`checkReSetCryptKey(@Nullable() String cryptKey)`	Just reset the encryption key (will not encrypt or decrypt anything).
`static native int`	`pageSize()`
`static native String`	`version()`
`native String`	`mmapID()`
`native void`	`lock()`	Exclusively inter-process lock the MMKV instance.It will block and wait until it successfully locks the file.
`native void`	`unlock()`	Exclusively inter-process unlock the MMKV instance.
`native boolean`	`tryLock()`	Try exclusively inter-process lock the MMKV instance.It will not block if the file has already been locked by another process.
`boolean`	`encode(String key, boolean value)`
`boolean`	`encode(String key, boolean value, int expireDurationInSecond)`	Set value with customize expiration in seconds.
`boolean`	`decodeBool(String key)`
`boolean`	`decodeBool(String key, boolean defaultValue)`
`boolean`	`encode(String key, int value)`
`boolean`	`encode(String key, int value, int expireDurationInSecond)`	Set value with customize expiration in seconds.
`int`	`decodeInt(String key)`
`int`	`decodeInt(String key, int defaultValue)`
`boolean`	`encode(String key, long value)`
`boolean`	`encode(String key, long value, int expireDurationInSecond)`	Set value with customize expiration in seconds.
`long`	`decodeLong(String key)`
`long`	`decodeLong(String key, long defaultValue)`
`boolean`	`encode(String key, float value)`
`boolean`	`encode(String key, float value, int expireDurationInSecond)`	Set value with customize expiration in seconds.
`float`	`decodeFloat(String key)`
`float`	`decodeFloat(String key, float defaultValue)`
`boolean`	`encode(String key, double value)`
`boolean`	`encode(String key, double value, int expireDurationInSecond)`	Set value with customize expiration in seconds.
`double`	`decodeDouble(String key)`
`double`	`decodeDouble(String key, double defaultValue)`
`boolean`	`encode(String key, @Nullable() String value)`
`boolean`	`encode(String key, @Nullable() String value, int expireDurationInSecond)`	Set value with customize expiration in seconds.
`String`	`decodeString(String key)`
`String`	`decodeString(String key, @Nullable() String defaultValue)`
`boolean`	`encode(String key, @Nullable() Set<String> value)`
`boolean`	`encode(String key, @Nullable() Set<String> value, int expireDurationInSecond)`	Set value with customize expiration in seconds.
`Set<String>`	`decodeStringSet(String key)`
`Set<String>`	`decodeStringSet(String key, @Nullable() Set<String> defaultValue)`
`Set<String>`	`decodeStringSet(String key, @Nullable() Set<String> defaultValue, Class<out Set> cls)`
`boolean`	`encode(String key, @Nullable() Array<byte> value)`
`boolean`	`encode(String key, @Nullable() Array<byte> value, int expireDurationInSecond)`	Set value with customize expiration in seconds.
`Array<byte>`	`decodeBytes(String key)`
`Array<byte>`	`decodeBytes(String key, @Nullable() Array<byte> defaultValue)`
`boolean`	`encode(String key, @Nullable() Parcelable value)`
`boolean`	`encode(String key, @Nullable() Parcelable value, int expireDurationInSecond)`	Set value with customize expiration in seconds.
`<T extends Parcelable> T`	`decodeParcelable(String key, Class<T> tClass)`
`<T extends Parcelable> T`	`decodeParcelable(String key, Class<T> tClass, @Nullable() T defaultValue)`
`int`	`getValueSize(String key)`	Get the actual size consumption of the key's value.Note: might be a little bigger than value's length.
`int`	`getValueActualSize(String key)`	Get the actual size of the key's value.
`boolean`	`containsKey(String key)`	Check whether or not MMKV contains the key.
`Array<String>`	`allKeys()`
`Array<String>`	`allNonExpireKeys()`
`long`	`count()`
`long`	`countNonExpiredKeys()`
`long`	`totalSize()`	Get the size of the underlying file.
`long`	`actualSize()`	Get the actual used size of the MMKV instance.This size might increase and decrease as MMKV doing insertion and full write back.
`void`	`removeValueForKey(String key)`
`native void`	`removeValuesForKeys(Array<String> arrKeys)`	Batch remove some keys from the MMKV instance.
`native void`	`clearAll()`	Clear all the key-values inside the MMKV instance.
`native void`	`clearAllWithKeepingSpace()`	Faster clearAll implementationThe file size is kept as previous for later use
`native void`	`trim()`	The totalSize of an MMKV instance won't reduce after deleting key-values,call this method after lots of deleting if you care about disk usage.
`long`	`importFrom(MMKV src)`	import all key-value items from src
`native void`	`close()`	Call this method if the MMKV instance is no longer needed in the near future.Any subsequent call to any MMKV instances with the same ID is undefined behavior.
`native void`	`clearMemoryCache()`	Clear memory cache of the MMKV instance.You can call it on memory warning.Any subsequent call to the MMKV instance will trigger all key-values loading from the file again.
`void`	`sync()`	Save all mmap memory to file synchronously.You don't need to call this, really, I mean it.Unless you worry about the device running out of battery.
`void`	`async()`	Save all mmap memory to file asynchronously.No need to call this unless you worry about the device running out of battery.
`static boolean`	`isFileValid(String mmapID)`	Check whether the MMKV file is valid or not.Note: Don't use this to check the existence of the instance, the result is undefined on nonexistent files.
`static native boolean`	`isFileValid(String mmapID, @Nullable() String rootPath)`	Check whether the MMKV file is valid or not on customize folder.
`static boolean`	`removeStorage(String mmapID)`	remove the storage of the MMKV, including the data file & meta file (.
`static native boolean`	`removeStorage(String mmapID, @Nullable() String rootPath)`	remove the storage of the MMKV, including the data file & meta file (.
`static boolean`	`checkExist(String mmapID)`	check existence of the MMKV file
`static native boolean`	`checkExist(String mmapID, @Nullable() String rootPath)`	check existence of the MMKV file
`int`	`importFromSharedPreferences(@NonNull() SharedPreferences preferences)`	Atomically migrate all key-values from an existent SharedPreferences to the MMKV instance.
`static native boolean`	`backupOneToDirectory(String mmapID, String dstDir, @Nullable() String rootPath)`	backup one MMKV instance to dstDir
`static native boolean`	`restoreOneMMKVFromDirectory(String mmapID, String srcDir, @Nullable() String rootPath)`	restore one MMKV instance from srcDir
`static native long`	`backupAllToDirectory(String dstDir)`	backup all MMKV instance from default root dir to dstDir
`static native long`	`restoreAllFromDirectory(String srcDir)`	restore all MMKV instance from srcDir to default root dir
`native boolean`	`enableAutoKeyExpire(int expireDurationInSecond)`	Enable auto key expiration.
`native boolean`	`disableAutoKeyExpire()`	Disable auto key expiration.
`void`	`enableCompareBeforeSet()`	Enable data compare before set, for better performance.If data for key seldom changes, use it.When encryption or expiration is on, compare-before-set will be invalid.For encryption, compare operation must decrypt data which is time consuming.For expiration, compare is useless because in most cases the expiration time changes every time.
`native void`	`disableCompareBeforeSet()`	Disable data compare before setdisabled at default
`Map<String, out Object>`	`getAll()`	Intentionally Not Supported.
`String`	`getString(String key, @Nullable() String defValue)`
`SharedPreferences.Editor`	`putString(String key, @Nullable() String value)`
`SharedPreferences.Editor`	`putString(String key, @Nullable() String value, int expireDurationInSecond)`
`Set<String>`	`getStringSet(String key, @Nullable() Set<String> defValues)`
`SharedPreferences.Editor`	`putStringSet(String key, @Nullable() Set<String> values)`
`SharedPreferences.Editor`	`putStringSet(String key, @Nullable() Set<String> values, int expireDurationInSecond)`
`SharedPreferences.Editor`	`putBytes(String key, @Nullable() Array<byte> bytes)`
`SharedPreferences.Editor`	`putBytes(String key, @Nullable() Array<byte> bytes, int expireDurationInSecond)`
`Array<byte>`	`getBytes(String key, @Nullable() Array<byte> defValue)`
`int`	`getInt(String key, int defValue)`
`SharedPreferences.Editor`	`putInt(String key, int value)`
`SharedPreferences.Editor`	`putInt(String key, int value, int expireDurationInSecond)`
`long`	`getLong(String key, long defValue)`
`SharedPreferences.Editor`	`putLong(String key, long value)`
`SharedPreferences.Editor`	`putLong(String key, long value, int expireDurationInSecond)`
`float`	`getFloat(String key, float defValue)`
`SharedPreferences.Editor`	`putFloat(String key, float value)`
`SharedPreferences.Editor`	`putFloat(String key, float value, int expireDurationInSecond)`
`boolean`	`getBoolean(String key, boolean defValue)`
`SharedPreferences.Editor`	`putBoolean(String key, boolean value)`
`SharedPreferences.Editor`	`putBoolean(String key, boolean value, int expireDurationInSecond)`
`SharedPreferences.Editor`	`remove(String key)`
`SharedPreferences.Editor`	`clear()`	clearAll
`boolean`	`commit()`
`void`	`apply()`
`boolean`	`contains(String key)`
`SharedPreferences.Editor`	`edit()`
`void`	`registerOnSharedPreferenceChangeListener(SharedPreferences.OnSharedPreferenceChangeListener listener)`	Intentionally Not Supported by MMKV.
`void`	`unregisterOnSharedPreferenceChangeListener(SharedPreferences.OnSharedPreferenceChangeListener listener)`	Intentionally Not Supported by MMKV.
`static MMKV`	`mmkvWithAshmemFD(String mmapID, int fd, int metaFD, String cryptKey)`	Get an ashmem MMKV instance that has been initiated by another process.
`native int`	`ashmemFD()`
`native int`	`ashmemMetaFD()`
`static NativeBuffer`	`createNativeBuffer(int size)`	Create an native buffer, whose underlying memory can be directly transferred to another JNI method.Avoiding unnecessary JNI boxing and unboxing.
`static void`	`destroyNativeBuffer(@NonNull() NativeBuffer buffer)`	Destroy the native buffer.
`int`	`writeValueToNativeBuffer(String key, @NonNull() NativeBuffer buffer)`	Write the value of the key to the native buffer.
`static void`	`registerHandler(MMKVHandler handler)`	Register a handler for MMKV log redirecting, and error handling.
`static void`	`unregisterHandler()`	Unregister the handler for MMKV.
`static void`	`registerContentChangeNotify(MMKVContentChangeNotification notify)`	Register for MMKV inter-process content change notification.The notification will trigger only when any method is manually called on the MMKV instance.
`static void`	`unregisterContentChangeNotify()`	Unregister for MMKV inter-process content change notification.
`native void`	`checkContentChangedByOuterProcess()`	Check inter-process content change manually.
`native boolean`	`isMultiProcess()`	Check if this instance is in multi-process mode.
`native boolean`	`isReadOnly()`	Check if this instance is in read-only mode.

Methods inherited from class android.content.SharedPreferences
contains, edit, getAll, getBoolean, getFloat, getInt, getLong, getString, getStringSet, registerOnSharedPreferenceChangeListener, unregisterOnSharedPreferenceChangeListener
Methods inherited from class android.content.SharedPreferences.Editor
apply, clear, commit, putBoolean, putFloat, putInt, putLong, putString, putStringSet, remove
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - getRootDir
```
 static String getRootDir()
```
  - initialize
```
 static String initialize(@NonNull() Context context)
```
    Initialize MMKV with default configuration.You must call one of the initialize() methods on App startup process before using MMKV.
    
    Parameters:
    
    context - The context of Android App, usually from Application.
  - initialize
```
 static String initialize(@NonNull() Context context, MMKVLogLevel logLevel)
```
    Initialize MMKV with customize log level.You must call one of the initialize() methods on App startup process before using MMKV.
    
    Parameters:
    
    context - The context of Android App, usually from Application.
    
    logLevel - The log level of MMKV, defaults to LevelInfo.
  - initialize
```
 static String initialize(@NonNull() Context context, MMKV.LibLoader loader)
```
    Initialize MMKV with a 3rd library loader.You must call one of the initialize() methods on App startup process before using MMKV.
    
    Parameters:
    
    context - The context of Android App, usually from Application.
    
    loader - The 3rd library loader (for example, the ReLinker .
  - initialize
```
 static String initialize(@NonNull() Context context, MMKV.LibLoader loader, MMKVLogLevel logLevel)
```
    Initialize MMKV with a 3rd library loader, and customize log level.You must call one of the initialize() methods on App startup process before using MMKV.
    
    Parameters:
    
    context - The context of Android App, usually from Application.
    
    loader - The 3rd library loader (for example, the ReLinker .
    
    logLevel - The log level of MMKV, defaults to LevelInfo.
  - initialize
```
 static String initialize(Context context, String rootDir)
```
    Initialize MMKV with customize root folder.You must call one of the initialize() methods on App startup process before using MMKV.
    
    Parameters:
    
    context - The context of Android App, usually from Application.
    
    rootDir - The root folder of MMKV, defaults to $(FilesDir)/mmkv.
  - initialize
```
 static String initialize(Context context, String rootDir, MMKVLogLevel logLevel)
```
    Initialize MMKV with customize root folder, and log level.You must call one of the initialize() methods on App startup process before using MMKV.
    
    Parameters:
    
    context - The context of Android App, usually from Application.
    
    rootDir - The root folder of MMKV, defaults to $(FilesDir)/mmkv.
    
    logLevel - The log level of MMKV, defaults to LevelInfo.
  - initialize
```
 static String initialize(Context context, String rootDir, MMKV.LibLoader loader)
```
    Initialize MMKV with customize root folder, and a 3rd library loader.You must call one of the initialize() methods on App startup process before using MMKV.
    
    Parameters:
    
    context - The context of Android App, usually from Application.
    
    rootDir - The root folder of MMKV, defaults to $(FilesDir)/mmkv.
    
    loader - The 3rd library loader (for example, the ReLinker .
  - initialize
```
 static String initialize(Context context, String rootDir, MMKV.LibLoader loader, MMKVLogLevel logLevel)
```
    Initialize MMKV with customize settings.You must call one of the initialize() methods on App startup process before using MMKV.
    
    Parameters:
    
    context - The context of Android App, usually from Application.
    
    rootDir - The root folder of MMKV, defaults to $(FilesDir)/mmkv.
    
    loader - The 3rd library loader (for example, the ReLinker .
    
    logLevel - The log level of MMKV, defaults to LevelInfo.
  - initialize
```
 static String initialize(@NonNull() Context context, String rootDir, MMKV.LibLoader loader, MMKVLogLevel logLevel, MMKVHandler handler)
```
  - initialize
```
@Deprecated() static String initialize(String rootDir)
```
  - initialize
```
@Deprecated() static String initialize(String rootDir, MMKVLogLevel logLevel)
```
  - initialize
```
@Deprecated() static String initialize(String rootDir, MMKV.LibLoader loader)
```
  - initialize
```
@Deprecated() static String initialize(String rootDir, MMKV.LibLoader loader, MMKVLogLevel logLevel)
```
  - nameSpace
```
 static NameSpace nameSpace(String dir)
```
    Parameters:
    
    dir - the customize root directory of a NameSpace
  - defaultNameSpace
```
 static NameSpace defaultNameSpace()
```
    identical with the original MMKV with the global root dir
  - setLogLevel
```
 static void setLogLevel(MMKVLogLevel level)
```
    Set the log level of MMKV.
    
    Parameters:
    
    level - Defaults to LevelInfo.
  - onExit
```
 static native void onExit()
```
    Notify MMKV that App is about to exit. It's totally fine not calling it at all.
  - mmkvWithID
```
@NonNull() static MMKV mmkvWithID(String mmapID)
```
    Create an MMKV instance with an unique ID (in single-process mode).
    
    Parameters:
    
    mmapID - The unique ID of the MMKV instance.
  - mmkvWithID
```
@NonNull() static MMKV mmkvWithID(String mmapID, int mode)
```
    Create an MMKV instance in single-process or multi-process mode.
    
    Parameters:
    
    mmapID - The unique ID of the MMKV instance.
    
    mode - The process mode of the MMKV instance, defaults to SINGLE_PROCESS_MODE.
  - mmkvWithID
```
@NonNull() static MMKV mmkvWithID(String mmapID, int mode, long expectedCapacity)
```
    Create an MMKV instance in single-process or multi-process mode.
    
    Parameters:
    
    mmapID - The unique ID of the MMKV instance.
    
    mode - The process mode of the MMKV instance, defaults to SINGLE_PROCESS_MODE.
    
    expectedCapacity - The file size you expected when opening or creating file
  - mmkvWithID
```
@NonNull() static MMKV mmkvWithID(String mmapID, int mode, @Nullable() String cryptKey)
```
    Create an MMKV instance in customize process mode, with an encryption key.
    
    Parameters:
    
    mmapID - The unique ID of the MMKV instance.
    
    mode - The process mode of the MMKV instance, defaults to SINGLE_PROCESS_MODE.
    
    cryptKey - The encryption key of the MMKV instance (no more than 16 bytes).
  - mmkvWithID
```
@NonNull() static MMKV mmkvWithID(String mmapID, String rootPath)
```
    Create an MMKV instance in customize folder.
    
    Parameters:
    
    mmapID - The unique ID of the MMKV instance.
    
    rootPath - The folder of the MMKV instance, defaults to $(FilesDir)/mmkv.
  - mmkvWithID
```
@NonNull() static MMKV mmkvWithID(String mmapID, String rootPath, long expectedCapacity)
```
    Create an MMKV instance in customize folder.
    
    Parameters:
    
    mmapID - The unique ID of the MMKV instance.
    
    rootPath - The folder of the MMKV instance, defaults to $(FilesDir)/mmkv.
    
    expectedCapacity - The file size you expected when opening or creating file
  - mmkvWithID
```
@NonNull() static MMKV mmkvWithID(String mmapID, int mode, @Nullable() String cryptKey, String rootPath, long expectedCapacity)
```
    Create an MMKV instance with customize settings all in one.
    
    Parameters:
    
    mmapID - The unique ID of the MMKV instance.
    
    mode - The process mode of the MMKV instance, defaults to SINGLE_PROCESS_MODE.
    
    cryptKey - The encryption key of the MMKV instance (no more than 16 bytes).
    
    rootPath - The folder of the MMKV instance, defaults to $(FilesDir)/mmkv.
    
    expectedCapacity - The file size you expected when opening or creating file
  - mmkvWithID
```
@NonNull() static MMKV mmkvWithID(String mmapID, int mode, @Nullable() String cryptKey, String rootPath)
```
    Create an MMKV instance with customize settings all in one.
    
    Parameters:
    
    mmapID - The unique ID of the MMKV instance.
    
    mode - The process mode of the MMKV instance, defaults to SINGLE_PROCESS_MODE.
    
    cryptKey - The encryption key of the MMKV instance (no more than 16 bytes).
    
    rootPath - The folder of the MMKV instance, defaults to $(FilesDir)/mmkv.
  - backedUpMMKVWithID
```
@NonNull() static MMKV backedUpMMKVWithID(String mmapID, int mode, @Nullable() String cryptKey, String rootPath)
```
    Get an backed-up MMKV instance with customize settings all in one.
    
    Parameters:
    
    mmapID - The unique ID of the MMKV instance.
    
    mode - The process mode of the MMKV instance, defaults to SINGLE_PROCESS_MODE.
    
    cryptKey - The encryption key of the MMKV instance (no more than 16 bytes).
    
    rootPath - The backup folder of the MMKV instance.
  - mmkvWithAshmemID
```
@NonNull() static MMKV mmkvWithAshmemID(Context context, String mmapID, int size, int mode, @Nullable() String cryptKey)
```
    Create an MMKV instance base on Anonymous Shared Memory, aka not synced to any disk files.
    
    Parameters:
    
    context - The context of Android App, usually from Application.
    
    mmapID - The unique ID of the MMKV instance.
    
    size - The maximum size of the underlying Anonymous Shared Memory.Anonymous Shared Memory on Android can't grow dynamically, must set an appropriate size on creation.
    
    mode - The process mode of the MMKV instance, defaults to SINGLE_PROCESS_MODE.
    
    cryptKey - The encryption key of the MMKV instance (no more than 16 bytes).
  - defaultMMKV
```
@NonNull() static MMKV defaultMMKV()
```
    Create the default MMKV instance in single-process mode.
  - defaultMMKV
```
@NonNull() static MMKV defaultMMKV(int mode, @Nullable() String cryptKey)
```
    Create the default MMKV instance in customize process mode, with an encryption key.
    
    Parameters:
    
    mode - The process mode of the MMKV instance, defaults to SINGLE_PROCESS_MODE.
    
    cryptKey - The encryption key of the MMKV instance (no more than 16 bytes).
  - enableProcessModeChecker
```
 static void enableProcessModeChecker()
```
    Manually enable the process mode checker.By default, it's automatically enabled in DEBUG build, and disabled in RELEASE build.If it's enabled, MMKV will throw exceptions when an MMKV instance is created with mismatch process mode.
  - disableProcessModeChecker
```
 static void disableProcessModeChecker()
```
    Manually disable the process mode checker.By default, it's automatically enabled in DEBUG build, and disabled in RELEASE build.If it's enabled, MMKV will throw exceptions when an MMKV instance is created with mismatch process mode.
  - cryptKey
```
@Nullable() native String cryptKey()
```
  - reKey
```
 native boolean reKey(@Nullable() String cryptKey)
```
    Transform plain text into encrypted text, or vice versa by passing a null encryption key.You can also change existing crypt key with a different cryptKey.
    
    Parameters:
    
    cryptKey - The new encryption key (no more than 16 bytes).
  - checkReSetCryptKey
```
 native void checkReSetCryptKey(@Nullable() String cryptKey)
```
    Just reset the encryption key (will not encrypt or decrypt anything).Usually you should call this method after another process has reKey the multi-process MMKV instance.
    
    Parameters:
    
    cryptKey - The new encryption key (no more than 16 bytes).
  - pageSize
```
 static native int pageSize()
```
  - version
```
 static native String version()
```
  - mmapID
```
 native String mmapID()
```
  - lock
```
 native void lock()
```
    Exclusively inter-process lock the MMKV instance.It will block and wait until it successfully locks the file.It will make no effect if the MMKV instance is created with SINGLE_PROCESS_MODE.
  - unlock
```
 native void unlock()
```
    Exclusively inter-process unlock the MMKV instance.It will make no effect if the MMKV instance is created with SINGLE_PROCESS_MODE.
  - tryLock
```
 native boolean tryLock()
```
    Try exclusively inter-process lock the MMKV instance.It will not block if the file has already been locked by another process.It will make no effect if the MMKV instance is created with SINGLE_PROCESS_MODE.
  - encode
```
 boolean encode(String key, boolean value)
```
  - encode
```
 boolean encode(String key, boolean value, int expireDurationInSecond)
```
    Set value with customize expiration in seconds.
    
    Parameters:
    
    expireDurationInSecond - override the default duration, ExpireNever (0) means never expire.
  - decodeBool
```
 boolean decodeBool(String key)
```
  - decodeBool
```
 boolean decodeBool(String key, boolean defaultValue)
```
  - encode
```
 boolean encode(String key, int value)
```
  - encode
```
 boolean encode(String key, int value, int expireDurationInSecond)
```
    Set value with customize expiration in seconds.
    
    Parameters:
    
    expireDurationInSecond - override the default duration, ExpireNever (0) means never expire.
  - decodeInt
```
 int decodeInt(String key)
```
  - decodeInt
```
 int decodeInt(String key, int defaultValue)
```
  - encode
```
 boolean encode(String key, long value)
```
  - encode
```
 boolean encode(String key, long value, int expireDurationInSecond)
```
    Set value with customize expiration in seconds.
    
    Parameters:
    
    expireDurationInSecond - override the default duration, ExpireNever (0) means never expire.
  - decodeLong
```
 long decodeLong(String key)
```
  - decodeLong
```
 long decodeLong(String key, long defaultValue)
```
  - encode
```
 boolean encode(String key, float value)
```
  - encode
```
 boolean encode(String key, float value, int expireDurationInSecond)
```
    Set value with customize expiration in seconds.
    
    Parameters:
    
    expireDurationInSecond - override the default duration, ExpireNever (0) means never expire.
  - decodeFloat
```
 float decodeFloat(String key)
```
  - decodeFloat
```
 float decodeFloat(String key, float defaultValue)
```
  - encode
```
 boolean encode(String key, double value)
```
  - encode
```
 boolean encode(String key, double value, int expireDurationInSecond)
```
    Set value with customize expiration in seconds.
    
    Parameters:
    
    expireDurationInSecond - override the default duration, ExpireNever (0) means never expire.
  - decodeDouble
```
 double decodeDouble(String key)
```
  - decodeDouble
```
 double decodeDouble(String key, double defaultValue)
```
  - encode
```
 boolean encode(String key, @Nullable() String value)
```
  - encode
```
 boolean encode(String key, @Nullable() String value, int expireDurationInSecond)
```
    Set value with customize expiration in seconds.
    
    Parameters:
    
    expireDurationInSecond - override the default duration, ExpireNever (0) means never expire.
  - decodeString
```
@Nullable() String decodeString(String key)
```
  - decodeString
```
@Nullable() String decodeString(String key, @Nullable() String defaultValue)
```
  - encode
```
 boolean encode(String key, @Nullable() Set<String> value)
```
  - encode
```
 boolean encode(String key, @Nullable() Set<String> value, int expireDurationInSecond)
```
    Set value with customize expiration in seconds.
    
    Parameters:
    
    expireDurationInSecond - override the default duration, ExpireNever (0) means never expire.
  - decodeStringSet
```
@Nullable() Set<String> decodeStringSet(String key)
```
  - decodeStringSet
```
@Nullable() Set<String> decodeStringSet(String key, @Nullable() Set<String> defaultValue)
```
  - decodeStringSet
```
@Nullable() Set<String> decodeStringSet(String key, @Nullable() Set<String> defaultValue, Class<out Set> cls)
```
  - encode
```
 boolean encode(String key, @Nullable() Array<byte> value)
```
  - encode
```
 boolean encode(String key, @Nullable() Array<byte> value, int expireDurationInSecond)
```
    Set value with customize expiration in seconds.
    
    Parameters:
    
    expireDurationInSecond - override the default duration, ExpireNever (0) means never expire.
  - decodeBytes
```
@Nullable() Array<byte> decodeBytes(String key)
```
  - decodeBytes
```
@Nullable() Array<byte> decodeBytes(String key, @Nullable() Array<byte> defaultValue)
```
  - encode
```
 boolean encode(String key, @Nullable() Parcelable value)
```
  - encode
```
 boolean encode(String key, @Nullable() Parcelable value, int expireDurationInSecond)
```
    Set value with customize expiration in seconds.
    
    Parameters:
    
    expireDurationInSecond - override the default duration, ExpireNever (0) means never expire.
  - decodeParcelable
```
@Nullable() <T extends Parcelable> T decodeParcelable(String key, Class<T> tClass)
```
  - decodeParcelable
```
@Nullable() <T extends Parcelable> T decodeParcelable(String key, Class<T> tClass, @Nullable() T defaultValue)
```
  - getValueSize
```
 int getValueSize(String key)
```
    Get the actual size consumption of the key's value.Note: might be a little bigger than value's length.
    
    Parameters:
    
    key - The key of the value.
  - getValueActualSize
```
 int getValueActualSize(String key)
```
    Get the actual size of the key's value. String's length or byte[]'s length, etc.
    
    Parameters:
    
    key - The key of the value.
  - containsKey
```
 boolean containsKey(String key)
```
    Check whether or not MMKV contains the key.
    
    Parameters:
    
    key - The key of the value.
  - allKeys
```
@Nullable() Array<String> allKeys()
```
  - allNonExpireKeys
```
@Nullable() Array<String> allNonExpireKeys()
```
  - count
```
 long count()
```
  - countNonExpiredKeys
```
 long countNonExpiredKeys()
```
  - totalSize
```
 long totalSize()
```
    Get the size of the underlying file. Align to the disk block size, typically 4K for an Android device.
  - actualSize
```
 long actualSize()
```
    Get the actual used size of the MMKV instance.This size might increase and decrease as MMKV doing insertion and full write back.
  - removeValueForKey
```
 void removeValueForKey(String key)
```
  - removeValuesForKeys
```
 native void removeValuesForKeys(Array<String> arrKeys)
```
    Batch remove some keys from the MMKV instance.
    
    Parameters:
    
    arrKeys - The keys to be removed.
  - clearAll
```
 native void clearAll()
```
    Clear all the key-values inside the MMKV instance.The data file will be trimmed down to `pageSize`, and some sync operations will be calledIf you do not want to trim the file, use clearAllWithKeepingSpace instead for better performance
  - clearAllWithKeepingSpace
```
 native void clearAllWithKeepingSpace()
```
    Faster clearAll implementationThe file size is kept as previous for later use
  - trim
```
 native void trim()
```
    The totalSize of an MMKV instance won't reduce after deleting key-values,call this method after lots of deleting if you care about disk usage.Note that clearAll has a similar effect.
  - importFrom
```
 long importFrom(MMKV src)
```
    import all key-value items from src
  - close
```
 native void close()
```
    Call this method if the MMKV instance is no longer needed in the near future.Any subsequent call to any MMKV instances with the same ID is undefined behavior.
  - clearMemoryCache
```
 native void clearMemoryCache()
```
    Clear memory cache of the MMKV instance.You can call it on memory warning.Any subsequent call to the MMKV instance will trigger all key-values loading from the file again.
  - sync
```
 void sync()
```
    Save all mmap memory to file synchronously.You don't need to call this, really, I mean it.Unless you worry about the device running out of battery.
  - async
```
 void async()
```
    Save all mmap memory to file asynchronously.No need to call this unless you worry about the device running out of battery.
  - isFileValid
```
 static boolean isFileValid(String mmapID)
```
    Check whether the MMKV file is valid or not.Note: Don't use this to check the existence of the instance, the result is undefined on nonexistent files.
  - isFileValid
```
 static native boolean isFileValid(String mmapID, @Nullable() String rootPath)
```
    Check whether the MMKV file is valid or not on customize folder.
    
    Parameters:
    
    mmapID - The unique ID of the MMKV instance.
    
    rootPath - The folder of the MMKV instance, defaults to $(FilesDir)/mmkv.
  - removeStorage
```
 static boolean removeStorage(String mmapID)
```
    remove the storage of the MMKV, including the data file & meta file (.crc)Note: the existing instance (if any) will be closed & destroyed
    
    Parameters:
    
    mmapID - The unique ID of the MMKV instance.
  - removeStorage
```
 static native boolean removeStorage(String mmapID, @Nullable() String rootPath)
```
    remove the storage of the MMKV, including the data file & meta file (.crc)Note: the existing instance (if any) will be closed & destroyed
    
    Parameters:
    
    mmapID - The unique ID of the MMKV instance.
    
    rootPath - The folder of the MMKV instance, defaults to $(FilesDir)/mmkv.
  - checkExist
```
 static boolean checkExist(String mmapID)
```
    check existence of the MMKV file
    
    Parameters:
    
    mmapID - The unique ID of the MMKV instance.
  - checkExist
```
 static native boolean checkExist(String mmapID, @Nullable() String rootPath)
```
    check existence of the MMKV file
    
    Parameters:
    
    mmapID - The unique ID of the MMKV instance.
    
    rootPath - The folder of the MMKV instance, defaults to $(FilesDir)/mmkv.
  - importFromSharedPreferences
```
 int importFromSharedPreferences(@NonNull() SharedPreferences preferences)
```
    Atomically migrate all key-values from an existent SharedPreferences to the MMKV instance.
    
    Parameters:
    
    preferences - The SharedPreferences to import from.
  - backupOneToDirectory
```
 static native boolean backupOneToDirectory(String mmapID, String dstDir, @Nullable() String rootPath)
```
    backup one MMKV instance to dstDir
    
    Parameters:
    
    mmapID - the MMKV ID to backup
    
    dstDir - the backup destination directory
    
    rootPath - the customize root path of the MMKV, if null then backup from the root dir of MMKV
  - restoreOneMMKVFromDirectory
```
 static native boolean restoreOneMMKVFromDirectory(String mmapID, String srcDir, @Nullable() String rootPath)
```
    restore one MMKV instance from srcDir
    
    Parameters:
    
    mmapID - the MMKV ID to restore
    
    srcDir - the restore source directory
    
    rootPath - the customize root path of the MMKV, if null then restore to the root dir of MMKV
  - backupAllToDirectory
```
 static native long backupAllToDirectory(String dstDir)
```
    backup all MMKV instance from default root dir to dstDir
    
    Parameters:
    
    dstDir - the backup destination directory
  - restoreAllFromDirectory
```
 static native long restoreAllFromDirectory(String srcDir)
```
    restore all MMKV instance from srcDir to default root dir
    
    Parameters:
    
    srcDir - the restore source directory
  - enableAutoKeyExpire
```
 native boolean enableAutoKeyExpire(int expireDurationInSecond)
```
    Enable auto key expiration. This is a upgrade operation, the file format will change.And the file won't be accessed correctly by older version (v1.2.16) of MMKV.NOTICE: enableCompareBeforeSet will be invalid when Expiration is on
    
    Parameters:
    
    expireDurationInSecond - the expire duration for all keys, ExpireNever (0) means no default duration (aka each key will have it's own expire date)
  - disableAutoKeyExpire
```
 native boolean disableAutoKeyExpire()
```
    Disable auto key expiration. This is a downgrade operation.
  - enableCompareBeforeSet
```
 void enableCompareBeforeSet()
```
    Enable data compare before set, for better performance.If data for key seldom changes, use it.When encryption or expiration is on, compare-before-set will be invalid.For encryption, compare operation must decrypt data which is time consuming.For expiration, compare is useless because in most cases the expiration time changes every time.
  - disableCompareBeforeSet
```
 native void disableCompareBeforeSet()
```
    Disable data compare before setdisabled at default
  - getAll
```
 Map<String, out Object> getAll()
```
    Intentionally Not Supported. Because MMKV does type-eraser inside to get better performance.
  - getString
```
@Nullable() String getString(String key, @Nullable() String defValue)
```
  - putString
```
 SharedPreferences.Editor putString(String key, @Nullable() String value)
```
  - putString
```
 SharedPreferences.Editor putString(String key, @Nullable() String value, int expireDurationInSecond)
```
  - getStringSet
```
@Nullable() Set<String> getStringSet(String key, @Nullable() Set<String> defValues)
```
  - putStringSet
```
 SharedPreferences.Editor putStringSet(String key, @Nullable() Set<String> values)
```
  - putStringSet
```
 SharedPreferences.Editor putStringSet(String key, @Nullable() Set<String> values, int expireDurationInSecond)
```
  - putBytes
```
 SharedPreferences.Editor putBytes(String key, @Nullable() Array<byte> bytes)
```
  - putBytes
```
 SharedPreferences.Editor putBytes(String key, @Nullable() Array<byte> bytes, int expireDurationInSecond)
```
  - getBytes
```
 Array<byte> getBytes(String key, @Nullable() Array<byte> defValue)
```
  - getInt
```
 int getInt(String key, int defValue)
```
  - putInt
```
 SharedPreferences.Editor putInt(String key, int value)
```
  - putInt
```
 SharedPreferences.Editor putInt(String key, int value, int expireDurationInSecond)
```
  - getLong
```
 long getLong(String key, long defValue)
```
  - putLong
```
 SharedPreferences.Editor putLong(String key, long value)
```
  - putLong
```
 SharedPreferences.Editor putLong(String key, long value, int expireDurationInSecond)
```
  - getFloat
```
 float getFloat(String key, float defValue)
```
  - putFloat
```
 SharedPreferences.Editor putFloat(String key, float value)
```
  - putFloat
```
 SharedPreferences.Editor putFloat(String key, float value, int expireDurationInSecond)
```
  - getBoolean
```
 boolean getBoolean(String key, boolean defValue)
```
  - putBoolean
```
 SharedPreferences.Editor putBoolean(String key, boolean value)
```
  - putBoolean
```
 SharedPreferences.Editor putBoolean(String key, boolean value, int expireDurationInSecond)
```
  - remove
```
 SharedPreferences.Editor remove(String key)
```
  - clear
```
 SharedPreferences.Editor clear()
```
    clearAll
  - commit
```
@Deprecated() boolean commit()
```
  - apply
```
@Deprecated() void apply()
```
  - contains
```
 boolean contains(String key)
```
  - edit
```
 SharedPreferences.Editor edit()
```
  - registerOnSharedPreferenceChangeListener
```
 void registerOnSharedPreferenceChangeListener(SharedPreferences.OnSharedPreferenceChangeListener listener)
```
    Intentionally Not Supported by MMKV. We believe it's better not for a storage framework to notify the change of data.Check registerContentChangeNotify for a potential replacement on inter-process scene.
  - unregisterOnSharedPreferenceChangeListener
```
 void unregisterOnSharedPreferenceChangeListener(SharedPreferences.OnSharedPreferenceChangeListener listener)
```
    Intentionally Not Supported by MMKV. We believe it's better not for a storage framework to notify the change of data.
  - mmkvWithAshmemFD
```
@NonNull()@Contract(value = _, _, _, _ -> new) static MMKV mmkvWithAshmemFD(String mmapID, int fd, int metaFD, String cryptKey)
```
    Get an ashmem MMKV instance that has been initiated by another process.Normally you should just call mmkvWithAshmemID instead.
    
    Parameters:
    
    mmapID - The unique ID of the MMKV instance.
    
    fd - The file descriptor of the ashmem of the MMKV file, transferred from another process by binder.
    
    metaFD - The file descriptor of the ashmem of the MMKV crc file, transferred from another process by binder.
    
    cryptKey - The encryption key of the MMKV instance (no more than 16 bytes).
  - ashmemFD
```
 native int ashmemFD()
```
  - ashmemMetaFD
```
 native int ashmemMetaFD()
```
  - createNativeBuffer
```
@Nullable() static NativeBuffer createNativeBuffer(int size)
```
    Create an native buffer, whose underlying memory can be directly transferred to another JNI method.Avoiding unnecessary JNI boxing and unboxing.An NativeBuffer must be manually destroyNativeBuffer to avoid memory leak.
    
    Parameters:
    
    size - The size of the underlying memory.
  - destroyNativeBuffer
```
 static void destroyNativeBuffer(@NonNull() NativeBuffer buffer)
```
    Destroy the native buffer. An NativeBuffer must be manually destroy to avoid memory leak.
  - writeValueToNativeBuffer
```
 int writeValueToNativeBuffer(String key, @NonNull() NativeBuffer buffer)
```
    Write the value of the key to the native buffer.
  - registerHandler
```
 static void registerHandler(MMKVHandler handler)
```
    Register a handler for MMKV log redirecting, and error handling.
  - unregisterHandler
```
 static void unregisterHandler()
```
    Unregister the handler for MMKV.
  - registerContentChangeNotify
```
 static void registerContentChangeNotify(MMKVContentChangeNotification notify)
```
    Register for MMKV inter-process content change notification.The notification will trigger only when any method is manually called on the MMKV instance.For example checkContentChangedByOuterProcess.
    
    Parameters:
    
    notify - The notification handler.
  - unregisterContentChangeNotify
```
 static void unregisterContentChangeNotify()
```
    Unregister for MMKV inter-process content change notification.
  - checkContentChangedByOuterProcess
```
 native void checkContentChangedByOuterProcess()
```
    Check inter-process content change manually.
  - isMultiProcess
```
 native boolean isMultiProcess()
```
    Check if this instance is in multi-process mode.
  - isReadOnly
```
 native boolean isReadOnly()
```
    Check if this instance is in read-only mode.

Class MMKV

Nested Class Summary

Field Summary

Method Summary

Methods inherited from class android.content.SharedPreferences

Methods inherited from class android.content.SharedPreferences.Editor

Methods inherited from class java.lang.Object

Method Detail

getRootDir

initialize

initialize

initialize

initialize

initialize

initialize

initialize

initialize

initialize

initialize

initialize

initialize

initialize

nameSpace

defaultNameSpace

setLogLevel

onExit

mmkvWithID

mmkvWithID

mmkvWithID

mmkvWithID

mmkvWithID

mmkvWithID

mmkvWithID

mmkvWithID

backedUpMMKVWithID

mmkvWithAshmemID

defaultMMKV

defaultMMKV

enableProcessModeChecker

disableProcessModeChecker

cryptKey

reKey

checkReSetCryptKey

pageSize

version

mmapID

lock

unlock

tryLock

encode

encode

decodeBool

decodeBool

encode

encode

decodeInt

decodeInt

encode

encode

decodeLong

decodeLong

encode

encode

decodeFloat

decodeFloat

encode

encode

decodeDouble

decodeDouble

encode

encode

decodeString

decodeString

encode

encode

decodeStringSet

decodeStringSet

decodeStringSet

encode

encode