由于谷歌策略机制，camera无法在后台长时间运行，activity在判断camera进入后台后，会调用到
frameworks/av/services/camera/libcameraservice/common
template <typename TClientBase>
binder::Status Camera2ClientBase<TClientBase>::disconnect() {ATRACE_CALL();Mutex::Autolock icl(mBinderSerializationLock);binder::Status res = binder::Status::ok();// Allow both client and the media server to disconnect at all timesint callingPid = getCallingPid();if (callingPid != TClientBase::mClientPid &&callingPid != TClientBase::mServicePid) return res;ALOGV("Camera %s: Shutting down", TClientBase::mCameraIdStr.string());detachDevice();CameraService::BasicClient::disconnect();ALOGV("Camera %s: Shut down complete complete", TClientBase::mCameraIdStr.string());return res;
}
可以在这里修改，判断pid等于0，则直接返回。
但是正规方法还是应该在blockClientsForUid除判断包名来进行屏蔽