Android 给 app默认权限（不弹窗申请权限）

1.系统app

系统app的权限默认开启，大家应该都知道是修改DefaultPermissionGrantPolicy.java。

frameworks/base/services/core/java/com/android/server/pm/DefaultPermissionGrantPolicy.java

在grantDefaultSystemHandlerPermissions中可以看到

// Camera
Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
PackageParser.Package cameraPackage = getDefaultSystemHandlerActivityPackageLPr(
        cameraIntent, userId);
if (cameraPackage != null
        && doesPackageSupportRuntimePermissions(cameraPackage)) {
    grantRuntimePermissionsLPw(cameraPackage, CAMERA_PERMISSIONS, userId);
    grantRuntimePermissionsLPw(cameraPackage, MICROPHONE_PERMISSIONS, userId);
    grantRuntimePermissionsLPw(cameraPackage, STORAGE_PERMISSIONS, userId);
}
从上面这段代码就可以看到Camera中默认打开了CAMERA_PERMISSIONS, MICROPHONE_PERMISSIONS, STORAGE_PERMISSIONS这三个Dangerous Permission。

2.第三方app

手动安装的第三方app的权限默认开启是修改PackageManagerService.java。

frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java

在grantPermissionsLpw函数中添加如下代码

//Permissions for com.xxx.xxx
 if(pkg.packageName.contains("com.xxx.xxx")) {
          final int permsSize = pkg.requestedPermissions.size();
          for (int i=0; i<permsSize; i++) {
              final String name = pkg.requestedPermissions.get(i);
              final BasePermission bp = mSettings.mPermissions.get(name);
              if(null != bp && permissionsState.grantInstallPermission(bp) != PermissionsState.PERMISSION_OPERATION_FAILURE) {
                  Slog.d(TAG, "zrx--- grant permission " + name + " to package " + pkg.packageName);
                  changedInstallPermission = true;
              }
          }
      }
参考：

https://blog.youkuaiyun.com/u011280717/article/details/51819708

https://blog.youkuaiyun.com/fmc088/article/details/83063198