ActionBar in PreferenceActivity

问题:

In my application I am using the new Action Bar Compatibility sample from Google (located at <sdk>/samples/android-<version>/ActionBarCompat) which works great. The only problem I have is applying this to my PreferenceActivity in order to get a screen like the settings in the Android Market (see picture).

To fill the ActionBar with icons, each Activity must extend the ActionBarActivity class. The problem is that my Activity already extends PreferenceActivity and in Java classes can not extend more than one class.

There must be a way to get the ActionBar together with a PreferenceScreen. I would be glad if anybody could provide a solution for this common issue.

P.S.: A solution like in How to add a button to PreferenceScreen does not fit because the ActionBar is actually the title bar and so this is more a Java than a layout thing.

回答1:

Edit: My answer below is rather hacky and it seems like it is now outdated (for pre Android 3.0) Have a look at the other answers for less hacky and more current solutions ~pyko 2014-09-01

---

I managed to get it working - not sure if this is the nicest/cleanest solution, but it works.

Had to make the following changes:

1. Make a copy of ActionBarActivity and have the new class extend PreferenceActivity

   public abstract class ActionBarPreferenceActivity extends PreferenceActivity {
       // contents exactly the same as 'ActionBarActivity'
   }
   

2. Modify onCreate() in ActionBarHelperBase.java slightly - make a special case for PreferenceActivity classes

   @Override
   public void onCreate(Bundle savedInstanceState) {
       // If the activity is a PreferenceActivity, don't make the request
       if (!(mActivity instanceof PreferenceActivity)) {
           mActivity.requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
       }
   

3. Have your PreferenceActivity extend this class and add request for FEATURE_CUSTOM_TITLE before you call super.onCreate()

   public class MyPreferenceActivity extends ActionBarPreferenceActivity {
   
       @Override
       protected void onCreate(Bundle savedInstanceState) {
           requestWindowFeature(Window.FEATURE_CUSTOM_TITLE); // add this line
           super.onCreate(savedInstanceState);
           addPreferencesFromResource(R.xml.preferences);
           // etc etc
       }
   
       // etc etc
   }
   

As far as I can tell, changes 2 and 3 are needed because for PreferenceActivity:

"As soon as you call super.onCreate(), the ViewGroup will be set up and so, you are not allowed to change the Window's parameters." (see Oliver's comment to the answer)

I guess the order of how components in PreferenceActivity activities are created is different to plain Activity activities .

回答2:

If you want to try a PreferenceFragment implementation based on support-v4 Fragment:

https://github.com/kolavar/android-support-v4-preferencefragment

I´m using it by myself and it isnt much work turning PreferenceActivity into PreferenceFragment.

回答3:

Can you just clone the code for ActionBarActivity, and change "extends Activity" to "extends PreferenceActivity"? Then extend your new class instead of ActionBarActivity.

From all the Google apps I've seen, though, it seems unusual to put buttons in the action bar of a PreferenceActivity. If you're not putting buttons on it, you could just use a values-v11 alternate style resource to show the holo theme, and set that style in the manifest for your PreferenceActivity.

回答4:

I used in my application this actionbar https://github.com/johannilsson/android-actionbar and it's work great with this thread How to add a button to PreferenceScreen

回答5:

I'd like to thank to @pyko providing a great answer, but it has problem that it won't work well on HoneyComb and above. well you can have a hack way to get it around like @AndroidDev said; But @pyko is gonna pollute the ActionBarHelperBase class, and @AndroidDev isn't very transparent.The best way is to create ActionBarActivityPreferences who extends from PreferenceActivity; and in onCreate method, change the order of calling parent method:

@Override
protected void onCreate(Bundle savedInstanceState) {
    //IMPORTATNT: MAKE SURE actionBarHelper called before super;
    //as super oncreate of prefenceactivity is actuallying setting the content view
    mActionBarHelper.onCreate(savedInstanceState);
    super.onCreate(savedInstanceState);
}

why calls 'mActionBarHelper.onCreate(savedInstanceState);' before 'super.onCreate(savedInstanceState);' , that is because super (i.e. PreferenceActivity) is actually setting the content view in its onCreate method, which would cause crash ("requestFeature() must be called before adding content'). SO what you need do is to swap the order, make sure ' mActionBarHelper.onCreate(savedInstanceState);' is called before super. In this way, we don't need to pollute the 'ActionBarHelperBase' yet we keep SettingActivity very clean because we encapsulate the tricky detail to 'ActionBarActivityPreferences' and bang!

回答6:

You can easily add action bar in preference activity by the following changes:

In AndroidManifest.xml :

<activity
        android:name=".activity.SettingsActivity"
        android:theme="@style/SettingsTheme"
        android:label="Settings"/>

In v21/styles.xml

<style name="SettingsTheme" parent="@android:style/Theme.Material.Light.DarkActionBar">
    <item name="android:colorPrimary">@color/colorPrimary</item>
    <item name="android:colorPrimaryDark">@color/colorPrimaryDark</item>
</style>

In v14/styles.xml for Back API support:

<style name="SettingsTheme" parent="@android:style/Theme.Holo.Light.DarkActionBar">
    <item name="android:actionBarStyle">@style/ActionBar.V14.Movie.NoTitle</item>
</style>

回答7:

Thanks, just an update, you need to add an if statement before the Custom Title line to support HoneyComb and above.

if (Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB)
   requestWindowFeature(Window.FEATURE_CUSTOM_TITLE); 

回答8:

You can get a ActionBarSherlock lib and let you code extends SherlockPreference;