我正在使用带有激光扫描仪的PDA。为此,我正在大量使用BroadcastReceiver
。我有一个活动,该活动有一个BottomNavigationView
在三个片段之间切换。我正在这样使用BroadcastReceiver
:
package com.example.package.fragments;
public class MyFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
private final static String SCAN_ACTION = "scan.rcv.message";
ScanDevice sm;
private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
//Doing my work
}
};
public MyFragment () {
// Required empty public constructor
}
public static MyFragment newInstance(String param1, String param2) {
CarteGriseFragment fragment = new CarteGriseFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
sm = new ScanDevice();
IntentFilter filter = new IntentFilter();
filter.addAction(SCAN_ACTION);
getContext().registerReceiver(mReceiver, filter);
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_carte_grise, container, false);
return view;
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onResume() {
super.onResume();
sm = null;
LocalBroadcastManager.getInstance(getActivity()).unregisterReceiver(mReceiver);
}
@Override
public void onPause() {
super.onPause();
sm = null;
LocalBroadcastManager.getInstance(getActivity()).unregisterReceiver(mReceiver);
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
sm = null;
LocalBroadcastManager.getInstance(getActivity()).unregisterReceiver(mReceiver);
}
@Override
public void onDestroy() {
super.onDestroy();
sm = null;
LocalBroadcastManager.getInstance(getActivity()).unregisterReceiver(mReceiver);
}
@Override
public void onDestroyView() {
super.onDestroyView();
sm = null;
LocalBroadcastManager.getInstance(getActivity()).unregisterReceiver(mReceiver);
}
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
}
问题是,当我移至另一个片段时,第一个片段的BroadcastReceiver
继续在第二个片段中工作。实际上,当我在第二个片段中扫描内容时,第一个片段的BroadcastReceiver
被调用。我搜索了许多解决方案,正如您在上面的代码中看到的那样,我试图注销BroadcastReceiver
,但无法正常工作。
另一个片段的代码与上面的代码相似。
我猜问题在于导航视图中所有片段都保持可见状态,因此不会调用onPause。您可以尝试在setUserVisibleHint
isVisibleToUser = false
退订也许您可以使用RxJava。
您说“ 我有一项活动”。
像这样使用RxJava。
您只需要在活动中一个BroadcastReceiver。在触发“ onReceive”函数时将其列出,然后使用RxJava发送事件并在片段中侦听此事件。