当我尝试在onPreferenceChange监听器中显示ProgressDialog(简单的,微调器类型)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显示,但直到方法(在这种情况下为睡眠)完成.我究竟做错了什么？

解决方法:

您正在主UI空间线程上休眠,这会阻止操作系统处理您的应用程序事件.这将阻止您的应用重绘,正如您所发现的那样,可以防止新窗口实际出现.

不要睡觉,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);