問題描述

我有一個 AsyncTask，它在工作時顯示一個 progressDialog(它從 doInBackground 中調用 runOnUiThread 來顯示進度對話框).

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

在運行時，我想允許使用后退按鈕取消操作；其他人遇到了這個問題:返回按鈕不起作用，而progressDialog 正在運行

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

由于什么原因我無法回復該主題，因此不得不開始另一個?！(另一天的另一個問題)

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

我和 Sandy 有同樣的想法，但是當 progressDialog 顯示時，這段代碼從未被調用，這是為什么呢?我已經在我的主要活動類中實現了它，progressDialog 是否暫時將前臺焦點從我的類中移開?

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?

推薦答案

首先，您應該從 OnPreExecute 顯示您的對話框，將其隱藏在 OnPostExecute 中，并且 - 如有必要- 通過發布進度修改它.(參見這里)

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

現在回答您的問題:ProgressDialog.show() 可以將 OnCancelListener 作為參數.您應該提供一個在進度對話框實例上調用 cancel() 的方法.

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.

示例:

    @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();
                    }
                }
        );
    }

其中 _progressDialog 是 YourTask 的 ProgressDialog 成員.

where _progressDialog is a ProgressDialog member of YourTask.

此類在 API 級別 26 中已棄用.ProgressDialog 是一種模式對話框，它會阻止用戶與應用程序交互.反而使用此類，您應該使用進度指示器，例如ProgressBar，可以嵌入到應用程序的 UI 中.或者，您可以使用通知來通知用戶任務的進度.鏈接

This class was deprecated in API level 26. ProgressDialog is a modal dialog, which prevents the user from interacting with the app. Instead of using this class, you should use a progress indicator like ProgressBar, which can be embedded in your app's UI. Alternatively, you can use a notification to inform the user of the task's progress. LINK

這篇關于Android 后退按鈕和進度對話框的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！