How do I use PackageManager.addPreferredActivity()?

Question

In SDK 1.5 I was using the PackageManager class to set the preferred home screen to be my app using PackageManager.addPackageToPreferred(). In the new SDK (using 2.1) this has been deprecated so I'm trying to use addPreferredActivity() for the same result but it's not working as expected.

Some necessary background. I'm writing a lock screen replacement app so I want the home key to launch my app (which will already be running, hence having the effect of disabling the key). When the user "unlocks" the screen I intend to restore the mapping so everything works as normal.

In my AndroidManifest.xml I have:

<intent-filter>
    <action android:name="android.intent.action.MAIN" />
    <category android:name="android.intent.category.LAUNCHER" />
    <category android:name="android.intent.category.HOME"/>
    <category android:name="android.intent.category.DEFAULT" />
</intent-filter>
<uses-permission android:name="android.permission.SET_PREFERRED_APPLICATIONS">
</uses-permission>

In my code I have the following snippet:

// Set as home activity
// This is done so we can appear to disable the Home key.
PackageManager pm = getPackageManager();
//pm.addPackageToPreferred(getPackageName());
    
IntentFilter filter = new IntentFilter("android.intent.action.MAIN");
filter.addCategory("android.intent.category.HOME");
filter.addCategory("android.intent.category.DEFAULT");
    
ComponentName[] components = new ComponentName[] 
{
    new ComponentName("com.android.launcher", ".Launcher")
};
    
Context context = getApplicationContext();
ComponentName component = new ComponentName(context.getPackageName(),
MyApp.class.getName());
    
pm.clearPackagePreferredActivities("com.android.launcher");
pm.addPreferredActivity(filter, IntentFilter.MATCH_CATEGORY_EMPTY,
components, component);

The resulting behavior is that the app chooser comes up when I press the Home key, which indicates that the clearPackagePreferredActivities() call worked but my app did not get added as the preferred. Also, the first line in the log below says something about "dropping preferred activity for Intent":

04-06 02:34:42.379: INFO/PackageManager(1017): Result set changed, dropping preferred activity for Intent { act=android.intent.action.MAIN cat=[android.intent.category.HOME] flg=0x10200000 } type null

04-06 02:34:42.379: INFO/ActivityManager(1017): Starting activity: Intent { act=android.intent.action.MAIN cat=[android.intent.category.HOME] flg=0x10200000 cmp=android/com.android.internal.app.ResolverActivity }

Does anyone know what this first log message means? Maybe I'm not using the API correctly, any ideas? Any help would be greatly appreciated.

Answer 1

@afonseca: I was dealing with the same problem. Thanks for the code, I used it to start with. Also thanks Shimon. I merged his answer into mine. I've got the code working (on 1.6 and 2.1 update 1). It has been adjusted a little bit, but the 2 main change seem to be Shimons suggestion and: ".Launcher" was changed to "com.android.launcher.Launcher". The working code is posted below.

Ciao, a2ronus

PackageManager pm = getPackageManager();

IntentFilter filter = new IntentFilter();
filter.addAction("android.intent.action.MAIN");
filter.addCategory("android.intent.category.HOME");
filter.addCategory("android.intent.category.DEFAULT");

Context context = getApplicationContext();
ComponentName component = new ComponentName(context.getPackageName(), TestReplaceHomeAppActivity.class.getName());

ComponentName[] components = new ComponentName[] {new ComponentName("com.android.launcher", "com.android.launcher.Launcher"), component};

pm.clearPackagePreferredActivities("com.android.launcher");
pm.addPreferredActivity(filter, IntentFilter.MATCH_CATEGORY_EMPTY, components, component);

Answer 2

This answer may come a little late but API docs says for clearPackagePreferredActivities:

An application can only clear its own package(s).

So, I think that in "restoring the mapping" the only you can do is something like:

getPackageManager().clearPackagePreferredActivities(getPackageName());

and so clearing the default setting for HOME screen.