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 Detail

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 Detail

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.