程序包 com.android.volley.toolbox

类 ImageLoader

java.lang.Object
com.android.volley.toolbox.ImageLoader
public class ImageLoader extends Object
Helper that handles loading and caching images from remote URLs. The simple way to use this class is to call get(String, ImageListener) and to pass in the default image listener provided by getImageListener(ImageView, int, int). Note that all function calls to this class must be made from the main thead, and all responses will be delivered to the main thread as well.

  • 构造器详细资料

    • ImageLoader

      public ImageLoader(RequestQueue queue, ImageLoader.ImageCache imageCache)
      Constructs a new ImageLoader.
      参数:
      queue - The RequestQueue to use for making image requests.
      imageCache - The cache to use as an L1 cache.

  • 方法详细资料

    • getImageListener

      public static ImageLoader.ImageListener getImageListener(android.widget.ImageView view, int defaultImageResId, int errorImageResId)
      The default implementation of ImageListener which handles basic functionality of showing a default image until the network response is received, at which point it will switch to either the actual image or the error image.
      参数:
      view - The imageView that the listener is associated with.
      defaultImageResId - Default image resource ID to use, or 0 if it doesn't exist.
      errorImageResId - Error image resource ID to use, or 0 if it doesn't exist.

    • isCached

      public boolean isCached(String requestUrl, int maxWidth, int maxHeight)
      Checks if the item is available in the cache.
      参数:
      requestUrl - The url of the remote image
      maxWidth - The maximum width of the returned image.
      maxHeight - The maximum height of the returned image.
      返回:
      True if the item exists in cache, false otherwise.

    • isCached

      public boolean isCached(String requestUrl, int maxWidth, int maxHeight, android.widget.ImageView.ScaleType scaleType)
      Checks if the item is available in the cache.
      参数:
      requestUrl - The url of the remote image
      maxWidth - The maximum width of the returned image.
      maxHeight - The maximum height of the returned image.
      scaleType - The scaleType of the imageView.
      返回:
      True if the item exists in cache, false otherwise.

    • get

      public ImageLoader.ImageContainer get(String requestUrl, ImageLoader.ImageListener listener)
      Returns an ImageContainer for the requested URL. The ImageContainer will contain either the specified default bitmap or the loaded bitmap. If the default was returned, the ImageLoader will be invoked when the request is fulfilled.
      参数:
      requestUrl - The URL of the image to be loaded.

    • get

      public ImageLoader.ImageContainer get(String requestUrl, ImageLoader.ImageListener imageListener, int maxWidth, int maxHeight)
      Equivalent to calling get(String, ImageListener, int, int, ScaleType) with Scaletype == ScaleType.CENTER_INSIDE.

    • get

      public ImageLoader.ImageContainer get(String requestUrl, ImageLoader.ImageListener imageListener, int maxWidth, int maxHeight, android.widget.ImageView.ScaleType scaleType)
      Issues a bitmap request with the given URL if that image is not available in the cache, and returns a bitmap container that contains all of the data relating to the request (as well as the default image if the requested image is not available).
      参数:
      requestUrl - The url of the remote image
      imageListener - The listener to call when the remote image is loaded
      maxWidth - The maximum width of the returned image.
      maxHeight - The maximum height of the returned image.
      scaleType - The ImageViews ScaleType used to calculate the needed image size.
      返回:
      A container object that contains all of the properties of the request, as well as the currently available image (default if remote is not loaded).

    • makeImageRequest

      protected Request<android.graphics.Bitmap> makeImageRequest(String requestUrl, int maxWidth, int maxHeight, android.widget.ImageView.ScaleType scaleType, String cacheKey)

    • setBatchedResponseDelay

      public void setBatchedResponseDelay(int newBatchedResponseDelayMs)
      Sets the amount of time to wait after the first response arrives before delivering all responses. Batching can be disabled entirely by passing in 0.
      参数:
      newBatchedResponseDelayMs - The time in milliseconds to wait.

    • onGetImageSuccess

      protected void onGetImageSuccess(String cacheKey, android.graphics.Bitmap response)
      Handler for when an image was successfully loaded.
      参数:
      cacheKey - The cache key that is associated with the image request.
      response - The bitmap that was returned from the network.

    • onGetImageError

      protected void onGetImageError(String cacheKey, VolleyError error)
      Handler for when an image failed to load.
      参数:
      cacheKey - The cache key that is associated with the image request.