在子屏幕首选项中的actionBar中显示向上按钮

Question

我已经实现了我的偏好,如官方指南中所示.

我有一个PreferenceActivity,可以像这样创建PreferenceFragment:

 @Override
 protected void onCreate(Bundle savedInstanceState) 
 {
      super.onCreate(savedInstanceState);

      Bundle extras = getIntent().getExtras();
      if (extras != null) 
      {
          Bundle bundle = new Bundle();
          _widgetID = extras.getInt(GlobalSettings.EXTRA_WIDGET_ID); 
          bundle.putInt(GlobalSettings.EXTRA_WIDGET_ID, _widgetID);

          WidgetSettingsFragment fragment = new WidgetSettingsFragment();
          fragment.setArguments(bundle);

          getFragmentManager().beginTransaction().replace(android.R.id.content,
                        fragment).commit();
      }

 }

PreferenceFragment从资源加载首选项,它们包含一个首选项子屏幕,如下所示:

<PreferenceScreen  xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- opens a subscreen of settings -->
    <PreferenceScreen
        android:key="button_voicemail_category_key"
        android:title="@string/voicemail"
        android:persistent="false">
        <ListPreference
            android:key="button_voicemail_provider_key"
            android:title="@string/voicemail_provider" ... />
        <!-- opens another nested subscreen -->
        <PreferenceScreen
            android:key="button_voicemail_setting_key"
            android:title="@string/voicemail_settings"
            android:persistent="false">
            ...
        </PreferenceScreen>
        <RingtonePreference
            android:key="button_voicemail_ringtone_key"
            android:title="@string/voicemail_ringtone_title"
            android:ringtoneType="notification" ... />
        ...
    </PreferenceScreen>
    ...
</PreferenceScreen>

到目前为止这种方法效果很好,但现在我想up-Button在显示首选项子屏幕时在actionBar中有一个.知道怎么做到这一点？

我试图setDisplayHomeAsUpEnabled(true)在我的活动中设置,但是按钮只显示在主要首选项中(不应该在哪里),而不是在子屏幕中.

我想知道即使在官方文档中,子屏幕也没有活动的按钮显示:

链接到文档:设置

任何帮助都非常受欢迎

Answer 1

我终于开始工作了:D.它非常hacky但它​​的工作原理.

问题是,在xml-layouts中使用子屏幕导致一些"代码魔术".子屏幕启动了一个新的活动/对话框,您无法直接访问它.

要访问操作栏和主页/上行按钮的OnClickListener,您需要获取对PreferenceScreen的引用并获取其父对话框以访问操作栏及其主页/向上按钮.

这是我在PreferenceFragment中完成的方式:

 @Override
 public void onCreate(Bundle savedInstanceState) 
 {
...

 final PreferenceScreen preferenceScreen = (PreferenceScreen) findPreference(getString(R.string.keyPrefScreenDynamicWidgetDetails));
  preferenceScreen.setOnPreferenceClickListener(new OnPreferenceClickListener() 
  {
       public boolean onPreferenceClick(Preference preference) 
       {
           preferenceScreen.getDialog().getActionBar().setDisplayHomeAsUpEnabled(true);
           final Dialog dialog = preferenceScreen.getDialog();

           View homeBtn = dialog.findViewById(android.R.id.home);
           if (homeBtn != null) 
           {
               OnClickListener dismissDialogClickListener = new OnClickListener()
               {
                   @Override
                   public void onClick(View v) 
                   {
                      dialog.dismiss();
                   }
               };

               // Prepare yourselves for some hacky programming
               ViewParent homeBtnContainer = homeBtn.getParent();

               // The home button is an ImageView inside a FrameLayout
               if (homeBtnContainer instanceof FrameLayout) {
                   ViewGroup containerParent = (ViewGroup) homeBtnContainer.getParent();

                   if (containerParent instanceof LinearLayout) {
                       // This view also contains the title text, set the whole view as clickable
                       ((LinearLayout) containerParent).setOnClickListener(dismissDialogClickListener);
                   } else {
                       // Just set it on the home button
                       ((FrameLayout) homeBtnContainer).setOnClickListener(dismissDialogClickListener);
                   }
               } else {
                   // The 'If all else fails' default case
                   homeBtn.setOnClickListener(dismissDialogClickListener);
               }                   
           }
           return true;
       }
  });
...

}

以下链接给了我最后的提示和代码来解决我的问题:

操作栏主页按钮无法使用嵌套的PreferenceScreen