当用户按下后退按钮时取消 AsyncTask

发布于 2024-09-30 03:42:56 字数 764 浏览 5 评论 0原文

我有一个 AsyncTask，其中在 onPreExecute 中显示一个 ProgressDialog，并在 onPostExecute 中再次隐藏它，就像

final class UploadTask extends AsyncTask {
   ProgressDialog dialog = new ProgressDialog(...);

   protected onPreExecute() {
      dialog.show();
   }
   protected onPostExecute() {
      dialog.hide();
   }
};

对话框是可以取消的，当我在 AsyncTask 执行期间按下取消按钮时，对话框确实会消失。

发生这种情况时，我想运行一些代码来取消 AsyncTask （现在，即使他 ProgressDialog 消失，AsyncTask 仍继续运行并最终完成）。我尝试从 ProgressDialog 派生我自己的类，然后执行

setOnDismissListener(new OnDismissListener() {
@Override public void onDismiss(DialogInterface d) {
   /* do something */
   }
};

（或使用 OnCancelListener 类似的操作），但这根本不会被调用。

有什么想法吗？我只需要一些机制让用户在显示 ProgressDialog 时取消正在运行的 AsyncTask。

原文

I have an AsyncTask in which I show a ProgressDialog in the onPreExecute, and hide it again in onPostExecute, something like

final class UploadTask extends AsyncTask {
   ProgressDialog dialog = new ProgressDialog(...);

   protected onPreExecute() {
      dialog.show();
   }
   protected onPostExecute() {
      dialog.hide();
   }
};

The dialog is cancellable and indeed goes away when I press the cancel button during execution of the AsyncTask.

When this happens, I would like to run some code to cancel the AsyncTask as well (right now, even thought he ProgressDialog goes away, the AsyncTask keeps running and eventually completes). I tried deriving my own class from ProgressDialog and then do

setOnDismissListener(new OnDismissListener() {
@Override public void onDismiss(DialogInterface d) {
   /* do something */
   }
};

(or something similar with an OnCancelListener), but this simply never gets called.

Any ideas? I just need some mechanism for the user to cancel a running AsyncTask while a ProgressDialog is showing.

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套路撩心 2024-10-07 03:42:56

我还没有测试过这个，但尝试这样的事情：

    final class UploadTask extends AsyncTask implements OnDismissListener{
       ProgressDialog dialog = new ProgressDialog(...);

       protected onPreExecute() {
           dialog.setOnDismissListener(this);
          dialog.show();
       }
       protected onPostExecute() {
          dialog.hide();
       }

       @Override
        public void onDismiss(DialogInterface dialog) {
            this.cancel(true);
        }
};

I haven't tested this, but try something like this:

    final class UploadTask extends AsyncTask implements OnDismissListener{
       ProgressDialog dialog = new ProgressDialog(...);

       protected onPreExecute() {
           dialog.setOnDismissListener(this);
          dialog.show();
       }
       protected onPostExecute() {
          dialog.hide();
       }

       @Override
        public void onDismiss(DialogInterface dialog) {
            this.cancel(true);
        }
};

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