在 PreferenceActivity 中显示 ProgressDialog

发布于 2024-09-12 07:00:39 字数 767 浏览 12 评论 0原文

当我尝试在 onPreferenceChange 侦听器中显示 ProgressDialog （简单的微调类型）时，我遇到了一个非常有趣的问题。

public class SettingsActivity extends PreferenceActivity {
  private ProgressDialog dialog;

  public void onCreate(Bundle savedInstanceState) {
    ListPreference pref= (ListPreference) findPreference("myPreference");  
    pref.setOnPreferenceChangeListener(new OnPreferenceChangeListener() {

      @Override
      public boolean onPreferenceChange(Preference preference, Object newValue) {
        dialog = ProgressDialog.show(SettingsActivity.this, "", "Doing stuff...", true);
        SystemClock.sleep(2000);
     }
    return true;
  }
}

ProgressDialog 会显示，但要等到该方法（在本例中为 sleep）完成后才会显示。我做错了什么？

原文

I've got a quite interesting issue when I try to display a ProgressDialog (the simple, spinner type) within a onPreferenceChange listener.

public class SettingsActivity extends PreferenceActivity {
  private ProgressDialog dialog;

  public void onCreate(Bundle savedInstanceState) {
    ListPreference pref= (ListPreference) findPreference("myPreference");  
    pref.setOnPreferenceChangeListener(new OnPreferenceChangeListener() {

      @Override
      public boolean onPreferenceChange(Preference preference, Object newValue) {
        dialog = ProgressDialog.show(SettingsActivity.this, "", "Doing stuff...", true);
        SystemClock.sleep(2000);
     }
    return true;
  }
}

The ProgressDialog shows up, but not until the method (sleep in this case) has finished. What am I doing wrong?

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月亮坠入山谷 2024-09-19 07:00:39

您正在主 UI 线程上休眠，这会阻止操作系统处理应用程序的事件。这将阻止您的应用程序重绘，并且正如您所发现的，可以阻止新窗口的实际出现。

与其睡觉，不如试试这个：

final ProgressDialog dialog = ProgressDialog.show(
    SettingsActivity.this, "", "Doing stuff...", true);
new Handler().postDelayed(new Runnable() {
    public void run() {
      dialog.hide();
    }
  }, 2000);

You're sleeping on the main UI thread, which stops the operating system from handling your application's events. This will stop your app from redrawing and as you discovered, can prevent new windows from actually appearing.

Instead of sleeping, try this:

final ProgressDialog dialog = ProgressDialog.show(
    SettingsActivity.this, "", "Doing stuff...", true);
new Handler().postDelayed(new Runnable() {
    public void run() {
      dialog.hide();
    }
  }, 2000);

回复收藏 0 原文

圈圈圆圆圈圈 2024-09-19 07:00:39

您可以使用 AsyncTask 在单独的线程中运行该函数（请参阅 http://developer.android.com/resources/articles/painless-threading.html）

如果您只想调用 sleep 方法，这可能有点不必要，但即使对于其他会阻塞 UI 线程的方法也应该有效。

你可以这样做：

private class BackgroundTask extends AsyncTask<Integer, Integer, void> {
    private ProgressDialog dialog;

    @Override
    protected void onPreExecute() {
        dialog = ProgressDialog.show(SettingsActivity.this, "", "Doing stuff...", true);
    }

    @Override
    protected void doInBackground(Integer... params) {
        sleep(params[0]);
    }

    @Override
    protected void onPostExecute(Boolean result) {
        dialog.dismiss();
    }
 }

然后使用下面的代码调用它：

new BackgroundTask().execute(2000);

You can use AsyncTask to run the function in a separate thread (see http://developer.android.com/resources/articles/painless-threading.html)

This is probably a bit unnecessary if you just want to invoke a sleep method, but should work even for other methods that otherwise would block the UI thread.

You could do something like this:

private class BackgroundTask extends AsyncTask<Integer, Integer, void> {
    private ProgressDialog dialog;

    @Override
    protected void onPreExecute() {
        dialog = ProgressDialog.show(SettingsActivity.this, "", "Doing stuff...", true);
    }

    @Override
    protected void doInBackground(Integer... params) {
        sleep(params[0]);
    }

    @Override
    protected void onPostExecute(Boolean result) {
        dialog.dismiss();
    }
 }

And than call it using the code below: