问题
At me, in the program there are two fragments each of which is responsible for one kind of messages - entering or proceeding.
There is an adapter that implements the selection of these fragments. And I want to make sure that when selecting a menu item, I saw a certain fragment, here is my main class menu:
public class MessageCenter extends AppCompatActivity
implements Sent.OnFragmentInteractionListener, Received.OnFragmentInteractionListener, OnNavigationItemSelectedListener {
PagerAdapter mAdapter;
FrameLayout mPager;
FragmentManager fragmentManager;
FragmentTransaction ft;
TextView txt1, txt2;
SharedPreferences sp;
SharedPreferences.Editor editor;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_message_center);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(MessageCenter.this, WriteResponseMess.class);
startActivity(intent);
}
});
txt1 = findViewById(R.id.id_app);
txt2 = findViewById(R.id.name_app);
DrawerLayout drawer = findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.addDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
/*mAdapter = new PagerAdapter(getSupportFragmentManager());
mPager = findViewById(R.id.frame);*/
navigationView.getMenu().findItem(R.id.received).setChecked(true);
fragmentManager = getSupportFragmentManager();
ft = fragmentManager.beginTransaction();
ft.replace(R.id.frame, new Received());
ft.commit();
getPersonalData();
}
@Override
public void onBackPressed() {
DrawerLayout drawer = findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
Intent intent = new Intent(MessageCenter.this, MainScreen.class);
startActivity(intent);
super.onBackPressed();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.home_menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.home) {
Intent intent = new Intent(getApplicationContext(), MainScreen.class);
startActivity(intent);
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
int id = item.getItemId();
Fragment fragment = null;
if (id == R.id.received) {
fragmentManager = getSupportFragmentManager();
ft = fragmentManager.beginTransaction();
ft.replace(R.id.frame, new Received());
ft.commit();
} else if (id == R.id.sended) {
fragmentManager = getSupportFragmentManager();
ft = fragmentManager.beginTransaction();
ft.replace(R.id.frame, new Sent());
ft.commit();
}
DrawerLayout drawer = findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
@Override
public void onFragmentInteraction(Uri uri) {
}
@Override
public void onPointerCaptureChanged(boolean hasCapture) {
}
}
But, I have only one fragment - Incoming messages, but the outgoing messages do not show me. Maybe I did not finish something somewhere, or there's a mistake somewhere.
Any help will be much useful. Thanks.
UPDATE
my Sent fragment:
public class Sent extends Fragment implements SwipeRefreshLayout.OnRefreshListener {
private OnFragmentInteractionListener mListener;
private RecyclerView recyclerView;
private RecyclerView.Adapter adapter;
ArrayList<Message> messageArrayList;
SwipeRefreshLayout mSwipeRefreshLayout;
private boolean isVisible;
private boolean isStarted;
SharedPreferences sp;
private Context context;
@Override
public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_sent, container, false);
recyclerView = rootView.findViewById(R.id.list_sen);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
mSwipeRefreshLayout = rootView.findViewById(R.id.refresh_1);
mSwipeRefreshLayout.setColorSchemeColors(Color.RED, Color.GREEN, Color.BLUE, Color.CYAN);
mSwipeRefreshLayout.setOnRefreshListener(this);
return rootView;
}
@Override
public void onRefresh() {
sent();
}
@Override
public void onStart() {
super.onStart();
isStarted = true;
if (isVisible) {
sent();
}
}
@Override
public void onStop() {
super.onStop();
isStarted = false;
}
@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
isVisible = isVisibleToUser;
if (isVisible && isStarted) {
sent();
}
}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
}
public void sent() {
HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
OkHttpClient client = new OkHttpClient.Builder().addInterceptor(interceptor).build();
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("https://0000/")
.client(client)
.addConverterFactory(GsonConverterFactory.create())
.build();
adapter = null;
sp = Objects.requireNonNull(context).getSharedPreferences("access_token", 0);
String a_token = sp.getString("access_token", "");
APIService mAPIService = retrofit.create(APIService.class);
mAPIService.getInMess("Bearer " + a_token, 1, 1).enqueue(new Callback<MessageArray>() {
@Override
public void onResponse(@NonNull Call<MessageArray> call, @NonNull Response<MessageArray> response) {
if (response.isSuccessful()) {
messageArrayList = (ArrayList<Message>) Objects.requireNonNull(response.body()).getMessages();
adapter = new MessageAdapter2(messageArrayList, getActivity());
recyclerView.setAdapter(adapter);
mSwipeRefreshLayout.setRefreshing(false);
} else {
ResponseBody errorBody = response.errorBody();
try {
if (Objects.requireNonNull(errorBody).string().contains("access_token_expired")) {
updateToken();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
@Override
public void onFailure(@NonNull Call<MessageArray> call, @NonNull Throwable t) {
}
});
}
public void updateToken() {
}
public void logOut() {
}
@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");
}
this.context = context;
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
}
my received fragent code:
public class Received extends Fragment implements SwipeRefreshLayout.OnRefreshListener {
private OnFragmentInteractionListener mListener;
private RecyclerView recyclerView;
private RecyclerView.Adapter adapter;
ArrayList<Message> messageArrayList;
SwipeRefreshLayout mSwipeRefreshLayout;
SharedPreferences sp;
@Override
public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_received, container, false);
recyclerView = rootView.findViewById(R.id.list_res);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
received();
mSwipeRefreshLayout = rootView.findViewById(R.id.refresh_2);
mSwipeRefreshLayout.setColorSchemeColors(Color.RED, Color.GREEN, Color.BLUE, Color.CYAN);
mSwipeRefreshLayout.setOnRefreshListener(this);
return rootView;
}
@Override
public void onRefresh() {
received();
}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
}
public void received() {
HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
OkHttpClient client = new OkHttpClient.Builder().addInterceptor(interceptor).build();
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("https://0000/")
.client(client)
.addConverterFactory(GsonConverterFactory.create())
.build();
adapter = null;
sp = Objects.requireNonNull(getActivity()).getSharedPreferences("access_token", 0);
String a_token = sp.getString("access_token", "");
final APIService mAPIService = retrofit.create(APIService.class);
mAPIService.getInMess("Bearer " + a_token, 0, 1).enqueue(new Callback<MessageArray>() {
@Override
public void onResponse(@NonNull Call<MessageArray> call, @NonNull Response<MessageArray> response) {
if (response.isSuccessful()) {
messageArrayList = (ArrayList<Message>) Objects.requireNonNull(response.body()).getMessages();
adapter = new MessageAdapter(messageArrayList, getActivity());
recyclerView.setAdapter(adapter);
mSwipeRefreshLayout.setRefreshing(false);
} else {
ResponseBody errorBody = response.errorBody();
try {
if (Objects.requireNonNull(errorBody).string().contains("access_token_expired")) {
updateToken();
} else if (errorBody.string().contains("invalid_token")) {
updateToken();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
@Override
public void onFailure(@NonNull Call<MessageArray> call, @NonNull Throwable t) {
}
});
}
public void updateToken() {
}
public void logOut() {
}
@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 onDetach() {
super.onDetach();
mListener = null;
}
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
}
回答1:
Solution:
First, declare two Global Classes:
public Class fragmentClass;
public Fragment fragment; // v4.Fragment not the app.Fragment
Secondly,
fragmentClass = VendorDriverFragment.class;
try {
fragment = (Fragment) fragmentClass.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
getSupportFragmentManager().beginTransaction().replace(R.id.content_frame, fragment).commit();
So, depending on the above strategy, modify as shown:
int id = item.getItemId();
if (id == R.id.received) {
fragmentClass = Recieved.class;
try {
fragment = (Fragment) fragmentClass.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
getSupportFragmentManager().beginTransaction().replace(R.id.content_frame, fragment).commit();
}
else if (id == R.id.sended) {
fragmentClass = Sent.class;
try {
fragment = (Fragment) fragmentClass.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
getSupportFragmentManager().beginTransaction().replace(R.id.content_frame, fragment).commit();
}
Don't forget to declare those two classes as public.
This works for me, Try it and if any problem comes, please comment.
来源：https://stackoverflow.com/questions/52115783/why-it-does-not-show-the-required-fragment-when-nav-drawer-android-menu-option-i