Android Open Source - SwitchTabs Asyn Image Loader

• Back to UI/viewpager  ↑

From Project

Back to project page SwitchTabs.

License

The source code is released under:

Apache License

Java Source Code

package com.normal.testdemo.utils;
//from   ww w .  j a  v  a  2 s. c  o  m
import android.graphics.Bitmap;
import android.os.Handler;
import android.util.Log;
import android.widget.ImageView;

import java.lang.ref.SoftReference;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;

/**
 * Created by ex_chenjinghao on 2014/4/8.
 * ????????????????
 */
public class AsynImageLoader {
  private LoaderThread thread;// ???????????????????????
  private HashMap<String, SoftReference<Bitmap>> imageCache;// ???????key:???url
  private Handler handler;// ????Activity?Handler??
  private Bitmap defaultBitmap, errorBitmap; // ?????????

  public AsynImageLoader(Handler handler, Bitmap defaultBitmap, Bitmap errorBitmap) {
    imageCache = new HashMap<String, SoftReference<Bitmap>>();
    this.handler = handler;
    this.defaultBitmap = defaultBitmap;
    this.errorBitmap = errorBitmap;
  }

  /**
   * ????????????ImageView?????url?????????Tag?
   *
   * @param imageView
   *            ?????????
   * @param defaultBitmap
   *            ???????????????????????
   */
  public void loadBitmap(ImageView imageView) {
    // ??????url,??????????????????????
    String url = (String) imageView.getTag();
    if (imageCache.containsKey(url)) {// ??????????
      SoftReference<Bitmap> softReference = imageCache.get(url);
      Bitmap bitmap = softReference.get();
      if (bitmap != null) {// ?????????????????????????
        imageView.setImageBitmap(bitmap);
        return;
      } else {// ??????????????????bitmap??????????????????
        Log.e("TAG", "cache bitmap is null");
        imageCache.remove(url);
      }
    }
    imageView.setImageBitmap(defaultBitmap);// ????????????????
    if (thread == null && url != null) {// ??????????????????????????????
      thread = new LoaderThread(imageView, url);
      thread.start();
    } else if (url != null) {// ???????????????
      thread.load(imageView, url);
    } else {// ?????????url???????????
      imageView.setImageBitmap(errorBitmap);
    }
  }

  /**
   * ????????Bitmap?????????
   */
  public void releaseBitmapCache() {
    if (imageCache != null) {
      for (Map.Entry<String, SoftReference<Bitmap>> entry : imageCache.entrySet()) {
        Bitmap bitmap = entry.getValue().get();
        if (bitmap != null) {
          bitmap.recycle();// ??bitmap??
        }
      }
      imageCache.clear();
    }
  }

  /**
   * ??????????
   */
  private class LoaderThread extends Thread {

    LinkedHashMap<String, ImageView> mTaskMap;// ????????????????????
    private boolean mIsWait;// ????????????????

    public LoaderThread(ImageView imageView, String url) {
      mTaskMap = new LinkedHashMap<String, ImageView>();
      mTaskMap.put(url, imageView);
    }

    /**
     * ??????????????
     * @param imageView
     */
    public void load(ImageView imageView, String url) {
      mTaskMap.remove(imageView);// ??????????????
      mTaskMap.put(url, imageView);// ????????
      if (mIsWait) {// ?????????????????????????????????
        synchronized (this) {// ?????notify()???????
          this.notify();
        }
      }
    }

    @Override
    public void run() {
      while (mTaskMap.size() > 0) {// ????????????????????,???????????????????
        mIsWait = false;
        final String url = mTaskMap.keySet().iterator().next();
        final ImageView imageView = mTaskMap.remove(url);
        if (url != null && imageView.getTag() == url) {// ?????????????ImageView??????tag?????????
          final Bitmap bitmap = Utils.getBitmapByUrl(url);// ??????????sd??????
          // ??????????map?
          imageCache.put(url, new SoftReference<Bitmap>(bitmap));
          if (url.equals(imageView.getTag())) {// ?????????????
            handler.post(new Runnable() {// ???????????????UI
              @Override
              public void run() {
                if (bitmap != null) {
                  imageView.setImageBitmap(bitmap);
                } else {
                  imageView.setImageBitmap(errorBitmap);
                }
              }
            });
          }
        }
        if (mTaskMap.isEmpty()) {// ???????????????????????????
          try {
            mIsWait = true;// ????????????wait()?????
            synchronized (this) {
              this.wait();// ????????????????????????????
            }
          } catch (InterruptedException e) {
            e.printStackTrace();
          }
        }
      }
    }
  }
}

Java Source Code List

• Back to UI/viewpager  ↑