com.codename1.components

Class InfiniteScrollAdapter

java.lang.Object

com.codename1.components.InfiniteScrollAdapter

public class InfiniteScrollAdapter
extends Object

Allows adapting a scroll container to scroll indefinitely (or at least until running out of data), this effectively works by showing an infinite progress indicator when reaching scroll end then allowing code to fetch additional components.

Warning: If you call Container.removeAll() on the container to which an InfiniteScrollAdapter is installed, it will disable the infinite scrolling behavior. You can re-enable infinite scrolling by calling addMoreComponents(com.codename1.ui.Container, com.codename1.ui.Component[], boolean) again.

The sample code shows the usage of the nestoria API to fill out an infinitely scrolling list.

Author:

Shai Almog

Method Summary

Modifier and Type	Method and Description
void	addMoreComponents(Component[] components, boolean areThereMore) Invoke this method to add additional components to the container, if you use addComponent/removeComponent you will get undefined behavior.
static void	addMoreComponents(Container cnt, Component[] components, boolean areThereMore) Invoke this method to add additional components to the container, if you use addComponent/removeComponent you will get undefined behavior.
void	continueFetching() If we previously added components with false for are there more this method can continue the process of fetching.
static void	continueFetching(Container cnt) If we previously added components with false for are there more this method can continue the process of fetching.
static InfiniteScrollAdapter	createInfiniteScroll(Container cont, Runnable fetchMore) Creates an instance of the InfiniteScrollAdapter that will invoke the fetch more callback to fetch additional components, once that method completes its task it should add the components via the addMoreComponents() invocation.
static InfiniteScrollAdapter	createInfiniteScroll(Container cont, Runnable fetchMore, boolean fetchOnCreate) Creates an instance of the InfiniteScrollAdapter that will invoke the fetch more callback to fetch additional components, once that method completes its task it should add the components via the addMoreComponents() invocation.
int	getComponentLimit() Deprecated. this feature has some inherent problems and doesn't work as expected
InfiniteProgress	getInfiniteProgress() Lets us manipulate the infinite progress object e.g.
void	setComponentLimit(int componentLimit) Deprecated. this feature has some inherent problems and doesn't work as expected

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

createInfiniteScroll

public static InfiniteScrollAdapter createInfiniteScroll(Container cont,
                                                         Runnable fetchMore)

Creates an instance of the InfiniteScrollAdapter that will invoke the fetch more callback to fetch additional components, once that method completes its task it should add the components via the addMoreComponents() invocation. Notice that the container MUST be empty when invoking this method, fetchMore will be invoked immediately and you can add your data when ready.

Parameters:

cont - the container to bind, it MUST be empty and must be scrollable on the Y axis

fetchMore - a callback that will be invoked on the EDT to fetch more data (do not block this method)

Returns:

an instance of this class that can be used to add components

createInfiniteScroll

public static InfiniteScrollAdapter createInfiniteScroll(Container cont,
                                                         Runnable fetchMore,
                                                         boolean fetchOnCreate)

Creates an instance of the InfiniteScrollAdapter that will invoke the fetch more callback to fetch additional components, once that method completes its task it should add the components via the addMoreComponents() invocation. Notice that the container MUST be empty when invoking this method, fetchMore will be invoked immediately and you can add your data when ready.

Parameters:

cont - the container to bind, it MUST be empty and must be scrollable on the Y axis

fetchMore - a callback that will be invoked on the EDT to fetch more data (do not block this method)

fetchOnCreate - if true the fetchMore callback is called upon calling this method

Returns:

an instance of this class that can be used to add components

addMoreComponents

public static void addMoreComponents(Container cnt,
                                     Component[] components,
                                     boolean areThereMore)

Invoke this method to add additional components to the container, if you use addComponent/removeComponent you will get undefined behavior. This is a convenience method saving the need to keep the InfiniteScrollAdapter as a variable

Parameters:

cnt - container to add the components to

components - the components to add

areThereMore - whether additional components exist

addMoreComponents

public void addMoreComponents(Component[] components,
                              boolean areThereMore)

Invoke this method to add additional components to the container, if you use addComponent/removeComponent you will get undefined behavior.

Parameters:

components - the components to add

areThereMore - whether additional components exist

continueFetching

public void continueFetching()

If we previously added components with false for are there more this method can continue the process of fetching. This is useful in case of a networking error. You can end fetching and then restart it based on user interaction see https://github.com/codenameone/CodenameOne/issues/2721

continueFetching

public static void continueFetching(Container cnt)

If we previously added components with false for are there more this method can continue the process of fetching. This is useful in case of a networking error. You can end fetching and then restart it based on user interaction see https://github.com/codenameone/CodenameOne/issues/2721

Parameters:

cnt - the container associated with the infinite scroll adapter

getComponentLimit

public int getComponentLimit()

Deprecated. this feature has some inherent problems and doesn't work as expected

The component limit defines the number of components that should be within the infinite scroll adapter, if more than component limit is added then the appropriate number of components is removed from the top. This prevents running out of memory or performance overhead with too many components... Notice that -1 is a special case value for no component limit.

Returns:

the componentLimit

setComponentLimit

public void setComponentLimit(int componentLimit)

Deprecated. this feature has some inherent problems and doesn't work as expected

The component limit defines the number of components that should be within the infinite scroll adapter, if more than component limit is added then the appropriate number of components is removed from the top. This prevents running out of memory or performance overhead with too many components... Notice that -1 is a special case value for no component limit.

Parameters:

componentLimit - the componentLimit to set

getInfiniteProgress

public InfiniteProgress getInfiniteProgress()

Lets us manipulate the infinite progress object e.g. set the animation image etc.

Returns:

the infinite progress component underlying this adapter