按下后退按钮时，AsyncTask杀死任务 [英] AsyncTask kill task when back button pressed

问题描述

我在使用AsyncTask时遇到一些问题.

I am having a little problems with AsyncTask.

我将其实现如下

 private class MakeConnection extends AsyncTask<String, Void, String> implements OnDismissListener{

    Context context;
    ProgressDialog myDialog;
    public MakeConnection(Context conetext)
    {
        this.context = conetext;
        myDialog = new ProgressDialog(this.context);
        myDialog.setCancelable(true);
        myDialog.setOnDismissListener(this);
    }

    @Override
    protected String doInBackground(String... urls) {
        //do stuff
    }

    @Override
    protected void onPostExecute(String result) {
        try {
            myDialog.dismiss();
            success(result);
        }catch(JSONException e)
        {
            data = e.toString();
        }
    }

    @Override
      protected void onProgressUpdate(Void... values) {
            myDialog = ProgressDialog.show(context, "Please wait...", "Loading the data", true);
       }

    @Override
    public void onDismiss(DialogInterface dialog) {

        this.cancel(true);
    }
}

但是当我按下后退按钮时，什么也没发生，它就像我没有按下后退按钮一样完成了任务

But when ever I press the back button nothing happens, it just completes the task as if I didn't press the back button

知道为什么吗?

推荐答案

此问题有两个部分:

1)以这种方式实现您的doInBackground()，以便它检查AsyncTask是否被取消.

1) Implement your doInBackground() in such a way, so it checks whether AsyncTask is cancelled.

 @Override
 protected String doInBackground(String... urls) {
       for(int i = 0; i < 100 && !isCancelled(); i++) { 
          //do some stuff
      }
}

2)您应该在活动的onDestroy()中调用asynTask.cancel(true).

2) You should call asynTask.cancel(true) in your Activity's onDestroy().

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