android 启动时自动设置default Launcher

转自：http://blog.csdn.net/pediyasm/article/details/7987389

设置default Launcher

系统有多个Launcher时，会在packages.xml 设置如下信息:


/data/system/packages.xml















如何在启动时自动设置default Launcher呢？

方法一：
在PackageManagerService构造函数中，会读取packages.xml文件：mRestoredSettings = mSettings.readLPw();
所以在之前添加设置：


readPermissions();
            
String firstBoot = SystemProperties.get("persist.sys.preactivity"); 
if ("0".equals(firstBoot)) {
    addPreferredActivityForULauncher();
}
SystemProperties.set("persist.sys.preactivity", "1");


mRestoredSettings = mSettings.readLPw();


private void addPreferredActivityForULauncher() {
    IntentFilter filter = new IntentFilter();
    filter.addAction("android.intent.action.MAIN");
    filter.addCategory("android.intent.category.HOME"); 
    filter.addCategory("android.intent.category.DEFAULT");
    ComponentName preActivity = new ComponentName("com.android.ulauncher", "com.android.ulauncher.Launcher"); 
    ComponentName[] set = new ComponentName[] {new ComponentName("com.android.launcher", "com.android.launcher2.Launcher"), preActivity}; 
    mSettings.mPreferredActivities.addFilter(
            new PreferredActivity(filter, IntentFilter.MATCH_CATEGORY_EMPTY, set, preActivity));
    scheduleWriteSettingsLocked();
}

方法二：

在ActivityManagerService 

 boolean startHomeActivityLocked() {
        
        /* launch the defualt launcher when the system boots for the first time */
setDefaultLauncher();

...

}

 private void setDefaultLauncher()
     {
         // get default component
         String  packageName = SystemProperties.get("ro.sw.defaultlauncherpackage", "no");
         String  className = SystemProperties.get("ro.sw.defaultlauncherclass", "no");
         Slog.i(TAG, "defautl packageName = " + packageName + ", default className = " + className);
         if(!packageName.equals("no") && !className.equals("no")){
             boolean firstLaunch = SystemProperties.getBoolean("persist.sys.sw.firstLaunch", true);
             Slog.d(TAG, "firstLaunch = " + firstLaunch);
             if(firstLaunch){
                 mFirstLaunch = true;
                 // do this only for the first boot
                 SystemProperties.set("persist.sys.sw.firstLaunch", "false");
             }
             Slog.d(TAG, "mFirstLaunch = " + mFirstLaunch);
             if(mFirstLaunch){
                 IPackageManager pm = ActivityThread.getPackageManager();

                 //clear the current preferred launcher
                 ArrayList intentList = new ArrayList();
                 ArrayList cnList = new ArrayList();
                 mContext.getPackageManager().getPreferredActivities(intentList, cnList, null);
                 IntentFilter dhIF;
                 for(int i = 0; i < cnList.size(); i++)
                 {
                     dhIF = intentList.get(i);
                     if(dhIF.hasAction(Intent.ACTION_MAIN) &&
                     dhIF.hasCategory(Intent.CATEGORY_HOME))
                     {
                         mContext.getPackageManager().clearPackagePreferredActivities(cnList.get(i).getPackageName());
                     }
                 }

                 // get all Launcher activities
                 Intent intent = new Intent(Intent.ACTION_MAIN);
                 intent.addCategory(Intent.CATEGORY_HOME);
                 List list = new ArrayList();
                 try
                 {
                     list = pm.queryIntentActivities(intent,
                         intent.resolveTypeIfNeeded(mContext.getContentResolver()),
                         PackageManager.MATCH_DEFAULT_ONLY);
                 }catch (RemoteException e) {
                     throw new RuntimeException("Package manager has died", e);
                 }
                 // get all components and the best match
                 IntentFilter filter = new IntentFilter();
                 filter.addAction(Intent.ACTION_MAIN);
                 filter.addCategory(Intent.CATEGORY_HOME);
                 filter.addCategory(Intent.CATEGORY_DEFAULT);
                 final int N = list.size();
                 ComponentName[] set = new ComponentName[N];
                 int bestMatch = 0;
                 for (int i = 0; i < N; i++)
                 {
                     ResolveInfo r = list.get(i);
                     set[i] = new ComponentName(r.activityInfo.packageName,
                                     r.activityInfo.name);
                     if (r.match > bestMatch) bestMatch = r.match;
                 }
                 // add the default launcher as the preferred launcher
                 ComponentName launcher = new ComponentName(packageName, className);
                 try
                 {
                     pm.addPreferredActivity(filter, bestMatch, set, launcher);
                 } catch (RemoteException e) {
                     throw new RuntimeException("Package manager has died", e);
                 }
             }
         }
     }