android-如何在按下后退按钮时停止异步任务执行

请我有一个包含异步任务方法的活动,即使用户已从该页面移出,该异步任务方法仍在后台继续执行.请提供一种方法,一旦用户按下“后退”按钮或从该页面移至另一页面,即可停止执行异步任务.

以下是我尝试过的方法,但无法正常工作

private AsyncTask totalLikesAsync;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity);
    context = this;

   totalLikesAsync = new TotalLikes().execute(msgiD);
}






@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.main, menu);

    return true;
}

@Override
public boolean onoptionsItemSelected(MenuItem menuItem) {
    switch (menuItem.getItemId()) {
        case android.R.id.home:

            totalLikesAsync.cancel(true);
            this.finish();
            break;

        case R.id.share:
            new ShareImage().execute(msgimage);
        default:
            return super.onoptionsItemSelected(menuItem);
    }
    return true;
}





private class TotalLikes extends AsyncTask<String, String, JSONObject> {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();

    }



    @Override
    protected JSONObject doInBackground(String... msgiDs) {
        UserFunctions userFunction = new UserFunctions();

        String msgsID = msgiDs[0];
        JSONObject json=null;

        if(!isCancelled()){

            //This gets all the information unread from the server
            json = userFunction.TotalLikes(context, msgsID);
        }

        return json;
    }

    @Override
    protected void onPostExecute(JSONObject json) {
        /**
         * Checks for success message.
         **/
        if (json != null) {

            ...
        } else {

           ...
        }

}
}

更新

测试完以下所有答案后,即使按下后退按钮,它们都允许在异步任务中执行doinbackground.我想要一种情况,一旦按下“后退”按钮,背景将被取消.

解决方法:

@Override
public void onBackpressed() {
    super.onBackpressed();
    if (totalLikesAsync != null && totalLikesAsync.getStatus().equals(AsyncTask.Status.RUNNING)) {
        totalLikesAsync.cancel(true);
    }
}