java - Android - 在等待来自 URL 的 ImageView 时显示进度对话框

Question

我正在从 URL 加载 ImageView ，并希望在等待图像加载时显示进度对话框，当我运行应用程序时，进度对话框出现大约半秒钟然后消失并且与图像的状态。如何才能使进度对话框仅在加载图像后消失？

下面是我的代码

//below is the download image task****************************************

private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
      ImageView bmImage;

      public DownloadImageTask(ImageView bmImage) {
          this.bmImage = bmImage;
      }

      protected Bitmap doInBackground(String... urls) {
          String urldisplay = urls[0];
          Bitmap mIcon11 = null;
          try {
            InputStream in = new java.net.URL(urldisplay).openStream();
            mIcon11 = BitmapFactory.decodeStream(in);
          } catch (Exception e) {
              Log.e("Error", e.getMessage());
              e.printStackTrace();
          }
          return mIcon11;
      }

      protected void onPostExecute(Bitmap result) {
          bmImage.setImageBitmap(result);
      }
    }

// above is the download imagetask ****************************************************

public class MyTask extends AsyncTask<Void, Void, Void> {
      private ProgressDialog progress;

    public MyTask(ProgressDialog progress) {
        this.progress = progress;
      }

      public void onPreExecute() {
        progress.show();
      }

      public void onPostExecute(Void unused) {

          progress.dismiss();
      }

    @Override
    protected Void doInBackground(Void... params) {
         new DownloadImageTask((ImageView) findViewById(R.id.ivget))
            .execute("http://dieboltdesigns.files.wordpress.com/2011/07/tom-brady-beast-poster-copy.png");

    //above makes the progress bar
        return null;
    }
    }

如果您需要 doinbackgound 方法/asynctask，请在评论中告诉我

谢谢

Answer 1

如果我没记错的话，问题是你在 AsyncTask 中使用了 AsyncTask。 DownloadImageTask 是另一个独立于当前线程的线程。那就是问题所在。

只需在MyTask中记下DownloadImageTask的所有代码即可。

编辑

private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
  ImageView bmImage;
  ProgressDialog pd;
  Context mContext;

  public DownloadImageTask(Context context,ImageView bmImage) {
      this.bmImage = bmImage;
      mContext = context;
  }

  public void onPreExecute() {
      pd = ProgressDialog.show(mContext, "dialog title","dialog message", true);   
  } 

  public void onPostExecute(Bitmap result) {
      pd.dismiss();
      if(result!=null)
          bmImage.setImageBitmap(result);
  }

  protected Bitmap doInBackground(String... urls) {
      String urldisplay = urls[0];
      Bitmap mIcon11 = null;
      try {
        InputStream in = new java.net.URL(urldisplay).openStream();
        mIcon11 = BitmapFactory.decodeStream(in);
      } catch (Exception e) {
          Log.e("Error", e.getMessage());
          e.printStackTrace();
      }
      return mIcon11;
  }
}