Android:ProgressDialog 不显示 [英] Android: ProgressDialog doesn't show

问题描述

我正在尝试为 Android 应用创建一个 ProgressDialog(只是一个简单的向用户展示正在发生的事情，没有按钮或任何东西)，但我无法正确完成.我已经浏览了论坛和教程以及 SDK 附带的示例代码，但无济于事.

I'm trying to create a ProgressDialog for an Android-App (just a simple one showing the user that stuff is happening, no buttons or anything) but I can't get it right. I've been through forums and tutorials as well as the Sample-Code that comes with the SDK, but to no avail.

这是我得到的:

    btnSubmit.setOnClickListener(new View.OnClickListener() {
      public void onClick(View view) {
        (...)
          ProgressDialog pd = new ProgressDialog(MyApp.this);
          pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
          pd.setMessage("Working...");
          pd.setIndeterminate(true);
          pd.setCancelable(false);

          // now fetch the results
          (...long time calculations here...)

          // remove progress dialog
          pd.dismiss();

我也尝试添加 pd.show(); 并在 new ProgressDialog 中处理参数导致什么都没有(除了所选参数的错误行不通)，意思是:ProgressDialog 永远不会出现.该应用程序一直在运行，就好像我从未添加过对话框一样.

I've also tried adding pd.show(); and messed around with the parameter in new ProgressDialog resulting in nothing at all (except errors that the chosen parameter won't work), meaning: the ProgressDialog won't ever show up. The app just keeps running as if I never added the dialog.

我不知道我是否在正确的位置创建了对话框，我稍微移动了它，但这也无济于事.也许我在错误的上下文中?上面的代码在MyApp的private ViewGroup _createInputForm()里面.

I don't know if I'm creating the dialog at the right place, I moved it around a bit but that, too, didnt't help. Maybe I'm in the wrong context? The above code is inside private ViewGroup _createInputForm() in MyApp.

感谢任何提示，

推荐答案

您必须在长计算开始之前调用 pd.show，然后计算必须在单独的线程中运行.该线程完成后，您必须立即调用 pd.dismiss() 关闭进程对话框.

you have to call pd.show before the long calculation starts and then the calculation has to run in a separate thread. A soon as this thread is finished, you have to call pd.dismiss() to close the prgoress dialog.

在这里你可以看到一个例子:

here you can see an example:

progressdialog 被创建并显示出来，并调用一个线程来运行一个繁重的计算:

the progressdialog is created and displayed and a thread is called to run a heavy calculation:

@Override
    public void onClick(View v) {
       pd = ProgressDialog.show(lexs, "Search", "Searching...", true, false);
       Search search = new Search(   ...   );
       SearchThread searchThread = new SearchThread(search);
       searchThread.start();
    }

这里是线程:

private class SearchThread extends Thread {

        private Search search;

        public SearchThread(Search search) {
            this.search = search;
        }

        @Override
        public void run() {         
            search.search();
            handler.sendEmptyMessage(0);
        }

        private Handler handler = new Handler() {

            @Override
            public void handleMessage(Message msg) {
                displaySearchResults(search);
                pd.dismiss();
            }
        };
    }

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