当我点击其他屏幕元素时,如何防止此Android列表视图中的图像移动？

Question

我之前发过另一篇关于这个主题的帖子,但我已经基于建议改变了我的代码,但存在同样的问题.如果我点击屏幕上的其他元素,我的图像会不断移动.

这是我的代码,我称之为:

new Thumbnailer(image_main,image_table).execute(image);

image_main是我的imageView,image_table是保存它的表.

 private class Thumbnailer extends AsyncTask<String, Void, Bitmap> {
      private ImageView imageView;
      private TableLayout imageTable;

        public Thumbnailer(ImageView imageView, TableLayout imageTable) {
            this.imageView = imageView;
            this.imageTable = imageTable;
        }

  @Override
  protected void onPostExecute(Bitmap result) {
      imageView.setImageBitmap(result);
               imageView.setVisibility(View.VISIBLE);
               imageTable.setVisibility(View.VISIBLE);
  }
  @Override
      protected void onProgressUpdate(Void... progress) {
      }

  @Override
  protected Bitmap doInBackground(String... params) {
         BitmapFactory.Options o = new BitmapFactory.Options();
          o.inJustDecodeBounds = true;
          BitmapFactory.decodeFile(params[0], o);
          final int REQUIRED_SIZE=70;

          //Find the correct scale value. It should be the power of 2.
          int width_tmp=o.outWidth, height_tmp=o.outHeight;
          int scale=1;
          while(true){
              if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE)
                  break;
              width_tmp/=2;
              height_tmp/=2;
              scale++;
          }
          //Decode with inSampleSize
          BitmapFactory.Options o2 = new BitmapFactory.Options();
          o2.inSampleSize=scale;       
          return BitmapFactory.decodeFile(params[0], o2);
  }
 }

Answer 1

我遇到了类似的问题.我会通过AsyncTask(可能通过HTTP获取图像)将图像加载到ListView中,并且在加载正确的图像之前,它似乎加载错误的图像一瞬间.就好像Android在HTTP请求完成之前重用该行,并且AsyncTasks有点碰撞.

上面的评论证实了正在发生的事情.

我通过在AsyncTask启动之前将图像路径放在ImageView的标记中来修复它,然后在AsyncTask完成之后但在它调用setImageBitmap之前检查该标记.

添加以下行:

final String somethingUnique = "put the image path or some other identifier here";
image_main.setTag(somethingUnique);

在此之前:

new Thumbnailer(image_main, image_table).execute(image);

现在,在onPostExecute中,检查标记:

// if this does not match, then the view has probably been reused
if (((String)imageView.getTag()).equals(somethingUnique)) {
  imageView.setImageBitmap(result);
}