不可行权限判断API：

context.checkCallingPermission

context.checkCallingOrSelfPermission

context.checkSelfPermission

PermissionChecker.checkSelfPermission

使用Camera中的mHasPermission

private boolean cameraHasPermission(Camera camera) throws ClassNotFoundException, NoSuchFieldException, IllegalAccessException {

if ((Build.VERSION.SDK_INT < Build.VERSION_CODES.M){

Class clazz = Class.forName(camera.getClass().getCanonicalName());Field mHasPermission = clazz.getDeclaredField("mHasPermission");mHasPermission.setAccessible(true);return mHasPermission.getBoolean(camera);}

}