Package com.castlabs.android.utils

Class LazyImageLoader

java.lang.Object
com.castlabs.android.utils.LazyImageLoader
public class LazyImageLoader extends Object
An instance of this class can be used to load images from a given URL as Bitmaps lazily and apply them to a given ImageView once loaded.

The image loader offers in-memory caching for bitmaps as well as local file caching for downloaded content.

This implementation manages its own executor thread and if you use it, make sure you shut down the image loader using the shutdown() method wither when all your resources are loaded, or, once the parent activity is destroyed. For example, in your activity use the image loader like this:

Note that the API needs WRITE_EXTERNAL_STORAGE permission which should be added and handled by the caller

private LazyImageLoader imageLoader; protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); this.imageLoader = new LazyImageLoader(this); } protected void onDestroy() { super.onDestroy(); this.imageLoader.shutdown(); }

Since:
1.0.0

  • Constructor Summary

    Constructors
    Constructor
    Description
    LazyImageLoader(Context context)
    Create a new lazy image loader for a given context
    LazyImageLoader(Context context, int defaultImg)
    Create a new lazy image loader for a give context with a default image id that is applied to all image views
    LazyImageLoader(Context context, String sdcardDirName, int defaultImg)
    Create a new lazy image loader for a give context with a default image id that is applied to all image views.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    clearCache()
    Clears the in-memory bitmap cache and removed all cached files.
    void
    loadImage(String url, ImageView imageView, int targetWidth)
    Asynchronously download the image from the given image URL and display the resulting bitmap on the corresponding ImageView.
    void
    loadImage(String url, String name, ImageView imageView, int targetWidth)
    Asynchronously download the image from the given image URL and display the resulting bitmap on the corresponding ImageView.
    void
    setPlaceHolder(ImageView imageView)
    Apply the configured placeholder drawable to the given image view.
    void
    shutdown()
    Shut down this image loader.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • LazyImageLoader

      public LazyImageLoader(@NonNull Context context)
      Create a new lazy image loader for a given context
      Parameters:
      context - the context

    • LazyImageLoader

      public LazyImageLoader(@NonNull Context context, @DrawableRes int defaultImg)
      Create a new lazy image loader for a give context with a default image id that is applied to all image views
      Parameters:
      context - the context
      defaultImg - resource id of a default image

    • LazyImageLoader

      public LazyImageLoader(@NonNull Context context, @Nullable String sdcardDirName, @DrawableRes int defaultImg)
      Create a new lazy image loader for a give context with a default image id that is applied to all image views. This image loader uses a sub directory created under the Environment.getExternalStorageDirectory() if its available.
      Parameters:
      context - teh context
      sdcardDirName - the sub folder name under Environment.getExternalStorageDirectory() used as cache folder
      defaultImg - the default image resource id

  • Method Details

    • loadImage

      public void loadImage(@NonNull String url, @NonNull ImageView imageView, int targetWidth)
      Asynchronously download the image from the given image URL and display the resulting bitmap on the corresponding ImageView.
      Parameters:
      url - Image download url
      imageView - View which will render the image
      targetWidth - If width is different from -1 the image will be scaled down while decoding. In-app memory will be saved
      Since:
      1.2.0

    • loadImage

      public void loadImage(@NonNull String url, @NonNull String name, @NonNull ImageView imageView, int targetWidth)
      Asynchronously download the image from the given image URL and display the resulting bitmap on the corresponding ImageView.
      Parameters:
      url - Image download url
      name - Image key name for cache
      imageView - View which will render the image
      targetWidth - If width is different from -1 the image will be scaled down while decoding. In-app memory will be saved
      Since:
      1.2.0

    • setPlaceHolder

      public void setPlaceHolder(@NonNull ImageView imageView)
      Apply the configured placeholder drawable to the given image view.
      Parameters:
      imageView - the image view

    • shutdown

      public void shutdown()
      Shut down this image loader. You will not be able to use it anymore after this method was called.
      Since:
      1.2.0

    • clearCache

      public void clearCache()
      Clears the in-memory bitmap cache and removed all cached files.