设置默认launcher

平台:android O

需求

手机中有多个launcher,需要给每个用户设置一个默认的Launcher(每类用户是同一个),考虑到android的多用户问题,不单是第一次开机要设置,每一次创建新的用户(user,guest,owner) 都要去设置一个默认的,并且要保证每个用户修改为自己喜欢的Launcher后,重启机器不能去覆盖用户的设置.

思路

1.在手机的’/data/system/users/‘目录下.有用户的列表,以及用户的文件夹,比如owner用户是0文件夹,在文件夹里有一个偏好设置保存的文件:package-restrictions.xml.
2.作为owner用户,可以在第一次开机的时候对其进行设置,作为其他用户可以在创建的时候去设置;

先把方案给出: 需要修改三个文件: frameworks/base/services/core/java/com/android/server/pm/UserManagerService.java frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java frameworks/base/packages/SystemUI/AndroidManifest.xml UserManagerService.java—>createUserInternalUnchecked

  1.         } finally {
  2.             Binder.restoreCallingIdentity(ident);
  3.         }
  4.         mPm.setDefaultLauncherAsUser(userId);//add
  5.         return userInfo;
  6.     }

PackageManagerService.java—>systemReady最后添加:
setDefaultLauncher();

在PackageManagerService.java添加两个方法: 

  1.     public void setDefaultLauncher(){
  2.        if(isFirstBoot()) {
  3.            setDefaultLauncherAsUser(0);//owner用户第一次开机进行设置
  4.        }
  5.     }
  7.     public void setDefaultLauncherAsUser(int userId){//给普通user用户和guest用户使用,
  8.         final PackageManager mPm = mContext.getPackageManager();
  10.         Intent homeIntent=new Intent();
  12.         homeIntent.addCategory(Intent.CATEGORY_HOME);
  13.         homeIntent.setAction(Intent.ACTION_MAIN);
  14.         homeIntent.addCategory(Intent.CATEGORY_DEFAULT);
  15.         String defaultLauncherPkg = "com.test.launcher";
  16.         String defaultLauncherClass = "com.test.launcher.Launcher");
  18.         ResolveInfo info = mPm.resolveActivity(homeIntent, PackageManager.MATCH_DEFAULT_ONLY);
  19.         ComponentName DefaultLauncher=new ComponentName(defaultLauncherPkg,defaultLauncherClass);
  21.         ArrayList<ResolveInfo> homeActivities = new ArrayList<ResolveInfo>();
  22.         ComponentName currentDefaultHome = mPm.getHomeActivities(homeActivities);
  23.         ComponentName[]mHomeComponentSet = new ComponentName[homeActivities.size()];
  24.         for (int i = 0; i < homeActivities.size(); i++) {
  25.             final ResolveInfo candidate = homeActivities.get(i);
  26.             final ActivityInfo activityInfo= candidate.activityInfo;
  27.             ComponentName activityName = new ComponentName(activityInfo.packageName, activityInfo.name);
  28.             mHomeComponentSet[i] = activityName;
  29.         }
  31.         IntentFilter mHomeFilter = new IntentFilter(Intent.ACTION_MAIN);
  32.         mHomeFilter.addCategory(Intent.CATEGORY_HOME);
  33.         mHomeFilter.addCategory(Intent.CATEGORY_DEFAULT);
  34.         mPm.addPreferredActivityAsUser(mHomeFilter, IntentFilter.MATCH_CATEGORY_EMPTY,mHomeComponentSet, DefaultLauncher, userId);
  35.     }

PackageManagerService.java—>findPreferredActivity 

  1.                             // Okay we found a previously set preferred or last chosen app.
  2.                             // If the result set is different from when this
  3.                             // was created, we need to clear it and re-ask the
  4.                             // user their preference, if we're looking for an "always" type entry.
  5.                             if (always && !pa.mPref.sameSet(query)) {
  6.                                 if (!(intent.getAction() != null
  7.                                         && intent.getAction().equals(intent.ACTION_MAIN)
  8.                                         && intent.getCategories() != null
  9.                                         && intent.getCategories().contains(intent.CATEGORY_HOME))) {//add 添加过滤条件
  10.                                 Slog.i(TAG, "Result set changed, dropping preferred activity for "
  11.                                         + intent + " type " + resolvedType);
  12.                                 if (DEBUG_PREFERRED) {
  13.                                     Slog.v(TAG, "Removing preferred activity since set changed "
  14.                                             + pa.mPref.mComponent);
  15.                                 }
  16.                                 pir.removeFilter(pa);
  17.                                 // Re-add the filter as a "last chosen" entry (!always)
  18.                                 PreferredActivity lastChosen = new PreferredActivity(
  19.                                         pa, pa.mPref.mMatch, null, pa.mPref.mComponent, false);
  20.                                 pir.addFilter(lastChosen);
  21.                                 changed = true;
  22.                                 return null;
  23.                             }
  24.                             }

在frameworks/base/packages/SystemUI/AndroidManifest.xml添加设置偏好的权限.
<uses-permission android:name="android.permission.SET_PREFERRED_APPLICATIONS" />

解决该问题遇到的坑以及参考的有价值的文章:

1号坑

网上有不少方案修改packages/apps/Provision,该方案是可行的,但是会带来问题
1.会设置两次默认值,导致第一次开机解锁后会出现闪屏;
2.开机时间加长.

2号坑

直接配置一个默认的xml,让其加载到默认设置package-restrictions.xml中. 很可惜,该方案对其他默认APP有效,对Launcher无效.具体分析参考:
[1] http://www.dxjia.cn/2016/03/08/aosp-default-application-setting/ “Android源码设置default application” [2] https://stackoverflow.com/questions/34073290/set-default-application-on-aosp “为什么不能设置Launcher?”

3号坑

如果不添加SET_PREFERRED_APPLICATIONS权限,在Launcher界面下拉菜单添加user或者guest导致system UI crash.

思考: 1.owner也是用户,可以将设置默认launcher的代码写在一个共同的节点代码.目前没有找到. 2.最好使用PackageManager.addPreferredActivityAsUser方法,PackageManager.replacePreferredActivityAsUser