Android How to - LruCache based Bitmap Cache

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Question

We would like to know how to lruCache based Bitmap Cache.

Answer

/*from  w  w  w  .  ja va2  s.  c  om*/
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
import android.util.LruCache;


 class BitmapCache {

  private static Context sAppContext;

  private static LruCache<Integer, Bitmap> sCache;

  private static final int SCALE = 1024; // Measure everything in KB

  public static void init(Context context) {
    sAppContext = context.getApplicationContext();

    // Use 1/4th of the available memory for this memory cache.
    final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / SCALE);
    final int cacheSize = maxMemory / 4;

    Log.i("MovieDemo", "Creating Bitmap cache size of: " + cacheSize + " (total memory " + maxMemory + ")");

    sCache = new LruCache<Integer, Bitmap>(cacheSize) {
      @Override
      protected int sizeOf(Integer key, Bitmap bitmap) {
        return bitmap.getByteCount() / SCALE;
      }
    };
  }

  public static Bitmap getBitmap(int drawableResId) {
    Bitmap bitmap = sCache.get(drawableResId);
    if (bitmap == null) {
      bitmap = BitmapFactory.decodeResource(sAppContext.getResources(), drawableResId);
      sCache.put(drawableResId, bitmap);
    }
    return bitmap;
  }
}

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