Question

我已经实现了一个ViewPager，它将容纳5个BitMap。我的图像每张不超过50kb。初始化ViewPager时，会先实例化前2个图像，但它们消耗的内存为100 MB！在第二张图像后，我的应用程序消耗大约256MB的内存，比我正常的内存使用量多190MB。这仅在3个图像创建后发生。（总计150KB）

我尝试解码BitMaps但没有用。我不知道为什么这么小的图像消耗了那么多的内存。图像幻灯片动画通常都是缓慢的。你知道我在哪里做错了吗？

日志

Initialize start
﹕ Position 0 is created
﹕ Position 1 is created
 Initialize end
Swipe Next image (1)
﹕ Position 2 is created
Swipe Next image (2)
﹕ Position 0 is destroyed
﹕ Position 3 is created
Swipe Next image (3)
﹕ Position 1 is destroyed
﹕ Position 4 is created
Swipe Next image (4)(last image)
﹕ Position 2 is destroyed
Swipe Previous image (3)
﹕ Position 2 is created
Swipe Previous image (2)
CRASHED

这是我的适配器

class CustomPagerAdapter extends PagerAdapter {

    Context mContext;
    LayoutInflater mLayoutInflater;

    public CustomPagerAdapter(Context context) {
        mContext = context;
        mLayoutInflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public int getCount() {
        return NUM_PAGES;
    }

    @Override
    public boolean isViewFromObject(View view, Object object) {
        return view == ((LinearLayout) object);
    }

    @Override
    public Object instantiateItem(ViewGroup collection, int position) {
        DebugLog.debug(TAG,"Position " + position + " is created");
        View itemView = mLayoutInflater.inflate(R.layout.pager_item, collection, false);
        ImageView imageView = (ImageView) itemView.findViewById(R.id.imageView);
                    Bitmap bitmap =  BitmapFactory.decodeResource(getResources(), mResources[position]);
        imageView.setImageBitmap(bitmap);
        collection.addView(itemView);
        return itemView;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        View view = (View)object;
        ImageView imageView = (ImageView) view.findViewById(R.id.imageView);
        BitmapDrawable bmpDrawable = (BitmapDrawable) imageView.getDrawable();
        if (bmpDrawable != null && bmpDrawable.getBitmap() != null) {
            bmpDrawable.getBitmap().recycle();
            DebugLog.debug(TAG, "Position " + position + " is destroyed");
        }
        container.removeView((LinearLayout) object);
        view = null;
    }
}

Answer 1

添加到您的适配器 private HashMap usedImages;

 ...
 public CustomPagerAdapter(Context context) {
   ...
    usedImages=new HashMap<>();
  }

  @Override
public Object instantiateItem(ViewGroup collection, int position) {
    DebugLog.debug(TAG,"Position " + position + " is created");
    View itemView = mLayoutInflater.inflate(R.layout.pager_item, collection, false);
    ImageView imageView = (ImageView) itemView.findViewById(R.id.imageView);
                Bitmap bitmap =  BitmapFactory.decodeResource(getResources(), mResources[position]);
    imageView.setImageBitmap(bitmap);
    usedImages.put(position, bitmap);          
    collection.addView(itemView);
    return itemView;
}


 @Override
public void destroyItem(ViewGroup container, int position, Object object) {
    View view = (View)object;
    ImageView imageView = (ImageView) view.findViewById(R.id.imageView);
    imageView.setImageBitmap(null);
    Bitmap bitmap = usedImages.get(position);
    if (bitmap != null) {
        bitmap.recycle();
        bitmap = null;
     }

    usedImages.remove(position);
    container.removeView(view);
}

将方法 clear（）添加到您的适配器，并在活动或片段的 onDestroy 中调用它：

public void clear(){
    if(usedImages!=null) {
        for (Map.Entry<Integer, Bitmap> item : usedImages.entrySet()) {
            Bitmap bitmap = item.getValue();
            if (bitmap != null) {
              bitmap.recycle();
              bitmap = null;
             }
        }
        usedImages.clear();
        usedImages = null;
    }
  mContext = null;
  mLayoutInflater=null;

}

使用位图 - OutOfMemoryError

1 个答案: