由网友(受大气，成大器)分享简介：我有我的活动，我用它来下载他们的LoveFilm队列中的用户片以下，但ProgressDialog永远不会出现。I have the following in my Activity that I use to download a users films in their LoveFilm queue, but t...

我有我的活动，我用它来下载他们的LoveFilm队列中的用户片以下，但ProgressDialog永远不会出现。

I have the following in my Activity that I use to download a users films in their LoveFilm queue, but the ProgressDialog never appears.

public class MyListActivity extends Activity {
    SharedPreferences prefs;
    ProgressDialog m_progressDialog;
    Thread listThread;
    User user;

    private Runnable threadProc_initializeQueue = new Runnable() {
        public void run() {
            user.fetchQueues();
            Queue defaultQueue = user.getDefaultQueue();
            defaultQueue.fetchTitles();

            m_progressDialog.dismiss();
        }
    };

    /* (non-Javadoc)
     * @see android.app.Activity#onCreate(android.os.Bundle)
     */
    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        prefs = getSharedPreferences(getString(R.string.app_name), MODE_PRIVATE);

        // Authenticate the user if needs be.
        if(!prefs.getBoolean("isAuthenticated", false)) {
            Intent i = new Intent(this, OAuthActivity.class);
            startActivity(i);
            finish();
        } else {
            // Get the users default list.
            LoveDroid app = (LoveDroid) getApplication();
            user = new User(app);

            m_progressDialog = ProgressDialog.show(MyListActivity.this, "Please Wait", "Loading", true);
            listThread = new Thread(null, threadProc_initializeQueue);
            listThread.run();
        }

    }

我见过别人这个问题，他们都基本上得到各地推荐的线路，看起来像我的

I've seen others with this problem, and they all basically get around to recommending a line that looks like mine

m_progressDialog = ProgressDialog.show(MyListActivity.this, "Please Wait", "Loading", true);

在code ++工程的其余部分，用户薄膜通过线程下载，但该对话框一直没有出现，它需要几秒钟也一样，它不是像对话被解雇之前，它是有时间出现

The rest of the code works, the users films are downloaded via the thread, but the dialog never shows up, it takes a few seconds too, it's not like the dialog is being dismissed before it's had time to appear.

推荐答案

这是更好，如果你使用的AsyncTask 。（而不是线程 - 这是Android的活动一般好的做法）

It's better if you use AsyncTask (instead of thread - it is generally good practice in Android activities).

创建的AsyncTask类，并在该类中添加进度上preExecute对话框，并在onPostExecute驳回。 你可以在这里找到一个例子。

Create an AsyncTask class, and on that class add a progress dialog at onPreExecute, and dismiss it at onPostExecute. You can find an example here.

除此之外，还有你的code的几个问题：

Other than that, there are a few problems in your code:

在调用ProgressDialog.show（...）在的onCreate（...）通常是有问题的（因为你不会看到它，直到的onCreate将完成，这是通常的方式后，你的背景活动已经结束了）。 在所有你的进度对话框的操作，应仅在UI线程执行的，所以你不能在一些随机的线程中使用m_pd.dismiss（）（这就是为什么你应该使用的