Android Open Source - SimpleReader Native Image Loader

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Back to project page SimpleReader.

License

The source code is released under:

Apache License

Java Source Code

package com.dreamteam.app.wallpaper;
// www  .  ja  v  a2s.  c  om
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import android.annotation.SuppressLint;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Point;
import android.os.Handler;
import android.os.Message;
import android.support.v4.util.LruCache;

public class NativeImageLoader {
  private LruCache<String, Bitmap> cache;
  private static NativeImageLoader instance;
  private ExecutorService threadPool;
  
  private NativeImageLoader() {
    threadPool = Executors.newFixedThreadPool(1);
    final int maxMemory = (int)Runtime.getRuntime().maxMemory() / 1024;
    final int cacheSize = maxMemory / 4;
    cache = new LruCache<String, Bitmap>(cacheSize) {
      @Override
      protected int sizeOf(String key, Bitmap value) {
        return value.getRowBytes() * value.getHeight() / 1024;
      }
    };
  }
  
  public static NativeImageLoader getInstance() {
    if(instance == null) {
      instance = new NativeImageLoader();
    }
    return instance;
  }
  
  public Bitmap loadImage(final String path, final OnImageLoadListener listener) {
    return loadImage(path, null, listener);
  }
   
  @SuppressLint("HandlerLeak")
  public Bitmap loadImage(final String path, final Point point, final OnImageLoadListener listener) {
    Bitmap result = loadFromCache(path);
    
    final Handler handler = new Handler() {
      @Override
      public void handleMessage(Message msg) {
        super.handleMessage(msg);
        listener.onImageLoad(path, (Bitmap)msg.obj);
      }
    };
    
    if(result == null) {
      threadPool.execute(new Runnable() {
        @Override
        public void run() {
          int width = 0;
          int height = 0;
          if(point != null) {
            width = point.x;
            height = point.y;
          }
          Bitmap bitmap = decodeBitmapFromFile(path, width, height);
          Message msg = handler.obtainMessage();
          msg.obj = bitmap;
          handler.sendMessage(msg);
          addToCache(path, bitmap);
        }
      });
    }
    return result;
  }
  
  public Bitmap decodeBitmapFromFile(String path, int width, int height) {
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeFile(path, options);
    options.inSampleSize = computeScale(options, width, height);
    options.inJustDecodeBounds = false;
    return BitmapFactory.decodeFile(path, options);
  }
  
  private int computeScale(BitmapFactory.Options options, int width, int height) {
    int inSampleSize = 1;
    if(width == 0 || height == 0) {
      return inSampleSize;
    }
    
    int bitmapWidth = options.outWidth;
    int bitmapHeight = options.outHeight;
    
    if(bitmapWidth > width || bitmapHeight > height) {
      int widthScale = Math.round((float)bitmapWidth / (float)width);
      int heightScale = Math.round((float)bitmapHeight / (float)height);
      
      inSampleSize = widthScale > heightScale ? heightScale : widthScale;
    }
    
    return inSampleSize;
  }
  
  private Bitmap loadFromCache(String key) {
    return cache.get(key);
  }
  
  private void addToCache(String key, Bitmap bitmap) {
    if(cache.get(key) == null && bitmap != null) {
      cache.put(key, bitmap);
    }
  }
  
  public interface OnImageLoadListener {
    public void onImageLoad(String path, Bitmap btimap);
  }
}

Java Source Code List

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