Android后退按钮和进度对话框 [英] Android Back Button and Progress Dialog

问题描述

我有一个AsyncTask ，它在工作时显示一个progressDialog（它从 doInBackground 中调用 runOnUiThread 来显示进度对话框） p>

虽然它的运行我想允许使用后退按钮取消操作;有其他人遇到此问题： BACK按钮不工作，而progressDialog正在运行

有什么原因我无法回复该线程，因此不得不启动另一个？ （另一天的另一个问题）

我和Sandy有同样的想法，但是在 progressDialog 显示时，这个代码从来没有被调用，为什么这个？我已经在我的主要活动类中实现了它，而进阶对话框是否将临时焦点从我的课程中脱离出来？

解决方案

首先，您应该从 OnPreExecute 中显示您的对话框，将其隐藏在 OnPostExecute 中，如果需要 - 通过发布进度来修改它。 （请参阅此处）

现在对于您的问题： ProgressDialog.show（）可以采用 OnCancelListener 作为参数。您应该在进度对话框实例上提供一个调用 cancel（）。

示例：

  @Override 
 protected void onPreExecute（）{
 _progressDialog = ProgressDialog.show（
 YourActivity.this，
标题，
消息，
 true，
 true，
 new DialogInterface.OnCancelListener（）{
 @Override 
 public void onCancel（DialogInterface对话框）{
 YourTask.this.cancel（true）; 
 finish（）; 
} 
} 
）; 
} 
  

其中 _progressDialog ProgressDialog 成员 YourTask 。

I have an AsyncTask that shows a progressDialog whilst working (it calls runOnUiThread from within doInBackground to show the progress dialog).

Whilst its running I want to allow the use of the back button to cancel the operation; someone else has had this problem: BACK Button is not working ,while progressDialog is running

For what ever reason I can't reply to that thread, hence having to start another?! (Another question for another day)

I had the same idea as Sandy but this code is never called whilst the progressDialog is showing, why is this? I have implemented it inside my main activity class, does the progressDialog take the foreground focus away from my class temporarily?

解决方案

First, you should show your dialog from OnPreExecute, hide it in OnPostExecute, and - if necessary - modify it by publishing progress. (see here)

Now to your question: ProgressDialog.show() can take a OnCancelListener as an argument. You should provide one that calls cancel() on the progress dialog instance.

example:

    @Override
    protected void onPreExecute(){
        _progressDialog = ProgressDialog.show(
                YourActivity.this,
                "Title",
                "Message",
                true,
                true,
                new DialogInterface.OnCancelListener(){
                    @Override
                    public void onCancel(DialogInterface dialog) {
                        YourTask.this.cancel(true);
                        finish();
                    }
                }
        );
    }

where _progressDialog is a ProgressDialog member of YourTask.

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