Android中有很多的应用想要取得设备管理器权限,成为系统设备管理器之后可以实现锁屏、擦除用户数据等功能,项目中客户希望自己的app能够默认成为系统的设备管理器,如何操作呢?,下面来介绍一下:
DevicePolicyManager mDPM = (DevicePolicyManager)mContext.getSystemService(Context.DEVICE_POLICY_SERVICE);if(!mDPM.isAdminActive(new ComponentName(PkgName,ClassName))){mDPM.setActiveAdmin(new ComponentName(PkgName,ClassName), false);}
首先获取DevicePolicyManager,然后通过DevicePolicyManager的isAdminActive方法判断当前要设置的应用是否已经是默认的设备管理器.如果不是的话,通过DevicePolicyManager的setActiveAdmin方法将它设置为默认设备管理器.
下面来看看DevicePolicyManager的isAdminActive方法具体做了什么,DevicePolicyManager的isAdminActive方法最终调用的是DevicePolicyManagerService的isAdminActive;
@Overridepublic boolean isAdminActive(ComponentName adminReceiver, int userHandle) {if (!mHasFeature) {return false;}enforceFullCrossUsersPermission(userHandle); //检查调用者权限synchronized (this) { //加了进程锁,防止阻塞return getActiveAdminUncheckedLocked(adminReceiver, userHandle) != null; //调用系统的getActiveAdminUncheckedLocked方法}}
接下来去看看getActiveAdminUncheckedLocked方法:
ActiveAdmin getActiveAdminUncheckedLocked(ComponentName who, int userHandle) {ActiveAdmin admin = getUserData(userHandle).mAdminMap.get(who); //通过当前应用的componentName来得到一个ActiveAdmin对象if (admin != null&& who.getPackageName().equals(admin.info.getActivityInfo().packageName)&& who.getClassName().equals(admin.info.getActivityInfo().name)) {return admin;}return null;}
getActiveAdminUncheckedLocked中通过getUserData(userHandle).mAdminMap.get(who)获取一个ActiveAdmin对象,
由于Android是支持多用户的,所以通过getUserData(userHandle)获取当前用户数据,默认的用户UserId是0,mAdminMap是一个ArrayMap,系统中的声明是ArrayMap<ComponentName, ActiveAdmin> mAdminMap = new ArrayMap<>();
如果判断不是默认设备管理器就会调用DevicePolicyManager的setActiveAdmin方法
/*** @param adminReceiver The admin to add* @param refreshing true = update an active admin, no error*/@Overridepublic void setActiveAdmin(ComponentName adminReceiver, boolean refreshing, int userHandle) {if (!mHasFeature) {return;}setActiveAdmin(adminReceiver, refreshing, userHandle, null); //这里调用的是私有方法setActiveAdmin}private void setActiveAdmin(ComponentName adminReceiver, boolean refreshing, int userHandle,Bundle onEnableData) {mContext.enforceCallingOrSelfPermission(android.Manifest.permission.MANAGE_DEVICE_ADMINS, null); //权限检查,这里检查的是用户是否有android.Manifest.permission.MANAGE_DEVICE_ADMINS权限,这个权限是需要签名权限或者priv-app下的应用才能使用enforceFullCrossUsersPermission(userHandle); //权限检查,这里检查的是不同用户之间的权限DevicePolicyData policy = getUserData(userHandle); //获取当前用户的DevicePolicyDataDeviceAdminInfo info = findAdmin(adminReceiver, userHandle,/* throwForMissionPermission= */ true); //获取当前用户的ComponentName获取DeviceAdminInfoif (info == null) {throw new IllegalArgumentException("Bad admin: " + adminReceiver);}if (!info.getActivityInfo().applicationInfo.isInternal()) {throw new IllegalArgumentException("Only apps in internal storage can be active admin: "+ adminReceiver);}synchronized (this) {long ident = mInjector.binderClearCallingIdentity();try {final ActiveAdmin existingAdmin= getActiveAdminUncheckedLocked(adminReceiver, userHandle); //取出系统当前默认的设备管理器if (!refreshing && existingAdmin != null) {throw new IllegalArgumentException("Admin is already added"); //如果refreshing为false,并且不存在默认设备管理器,直接报错~}if (policy.mRemovingAdmins.contains(adminReceiver)) { //如果设置当前用户DevicePolicyData中已经移除过的设备管理器,直接报错throw new IllegalArgumentException("Trying to set an admin which is being removed");}ActiveAdmin newAdmin = new ActiveAdmin(info, /* parent */ false); //新创建一个设备管理器newAdmin.testOnlyAdmin =(existingAdmin != null) ? existingAdmin.testOnlyAdmin: isPackageTestOnly(adminReceiver.getPackageName(), userHandle);policy.mAdminMap.put(adminReceiver, newAdmin); //把componentName和ActiveAdmin放到当前用户的DevicePolicyData的ArrayMap中int replaceIndex = -1;final int N = policy.mAdminList.size(); //获取当前DevicePolicyData中的mAdminList的大小for (int i=0; i < N; i++) {ActiveAdmin oldAdmin = policy.mAdminList.get(i);if (oldAdmin.info.getComponent().equals(adminReceiver)) { //找到默认设备管理器的位置,并将位置标记replaceIndex = i;break;}}if (replaceIndex == -1) {policy.mAdminList.add(newAdmin); //如果替换位置没有找到,添加新的AdminActive到mAdminList中enableIfNecessary(info.getPackageName(), userHandle);} else {policy.mAdminList.set(replaceIndex, newAdmin); //如果替换位置已经找到,就将当前的ActiveAdmin插入到该位置,替换为新的默认设备管理器}saveSettingsLocked(userHandle); //保存当前用户的设置sendAdminCommandLocked(newAdmin,DeviceAdminReceiver.ACTION_DEVICE_ADMIN_ENABLED,onEnableData, null); //发送通知给新的默认设备管理器} finally {mInjector.binderRestoreCallingIdentity(ident);}}}
如此如此就设置默认设备管理器完成了~
下面介绍有权查看使用情况的应用这个权限,这个权限是由AppOpsManager进行管理的:
AppOpsManager mAppOps = (AppOpsManager)mContext.getSystemService(Context.APP_OPS_SERVICE);ApplicationInfo info = mContext.getPackageManager().getApplicationInfo(pkgName, PackageManager.GET_ACTIVITIES); mAppOps.setMode(AppOpsManager.OP_GET_USAGE_STATS, info.uid, pkgName, AppOpsManager.MODE_ALLOWED);
这样就可以将应用的有权查看使用情况的应用权限打开了,拥有这个权限可以打印其他应用的使用情况,比如运行时间等等~
还有一个常见的权限是允许在其他应用上层显示,如何申请呢?
AppOpsManager mAppOps = (AppOpsManager)mContext.getSystemService(Context.APP_OPS_SERVICE);ApplicationInfo info = mContext.getPackageManager().getApplicationInfo(pkgName, PackageManager.GET_ACTIVITIES); mAppOps.setMode(AppOpsManager.OP_SYSTEM_ALERT_WINDOW,info.uid, PkgName, AppOpsManager.MODE_ALLOWED);
声明一下,AppOpsManager需要在系统service中调用才能生效,如果在普通系统应用中调用也是不可以的,比如SystemUI中,请注意这一点,我一般是在自定义的service中调用,自定义service请看我之前的文章~
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