如何禁用某些片段的底部导航

Question

你好，我在主活动中添加了底部导航，其余所有布局都是片段。现在我有一个登录片段，我不想显示底部导航，甚至不想单独包含每个片段的底部导航。有没有什么方法可以在一些片段中禁用底部导航，比如登录片段

如果您需要更多参考，请告诉我我会更新问题

Main_Activity.java

public class MainActivity extends AppCompatActivity {
BottomNavigationView bottomNavigationView;
Deque<Integer> integerDeque = new ArrayDeque<>(4);
boolean flag = true;
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
setContentView(R.layout.activity_main);
Window window = this.getWindow();
window.setStatusBarColor(this.getResources().getColor(R.color.black));
bottomNavigationView = findViewById(R.id.bottom_navigation_view);
integerDeque.push(R.id.nav_home);
loadFragments(new Home_Fragment());
bottomNavigationView.setSelectedItemId(R.id.nav_home);
bottomNavigationView.setOnNavigationItemSelectedListener(
item -> {
int id = item.getItemId();
if (integerDeque.contains(id)) {
if (id == R.id.nav_home) {
integerDeque.size();
if (flag) {
integerDeque.addFirst(R.id.nav_home);
flag = false;
}
}
integerDeque.remove(id);
}
integerDeque.push(id);
loadFragments(getFragment(item.getItemId()));
return false;
}
);
}
@SuppressLint("NonConstantResourceId")
private Fragment getFragment(int itemId) {
switch (itemId) {
case R.id.nav_home:
bottomNavigationView.getMenu().getItem(0).setChecked(true);
return new Home_Fragment();
case R.id.nav_following:
bottomNavigationView.getMenu().getItem(1).setChecked(true);
return new Following_Fragment();
case R.id.nav_upload:
bottomNavigationView.getMenu().getItem(2).setChecked(true);
return new Upload_Fragment();
case R.id.nav_notification:
bottomNavigationView.getMenu().getItem(3).setChecked(true);
return new Notification_Fragment();
case R.id.nav_profile:
bottomNavigationView.getMenu().getItem(4).setChecked(true);
return new Profile_Fragment();
}
bottomNavigationView.getMenu().getItem(0).setChecked(true);
return new Home_Fragment();
}
public void loadFragments(Fragment fragment) {
if (fragment != null) {
getSupportFragmentManager().beginTransaction()
.replace(R.id.fragment_container, fragment, fragment.getClass().getSimpleName())
.commit();
}
}
@Override
public void onBackPressed() {
integerDeque.pop();
if (!integerDeque.isEmpty()) {
loadFragments(getFragment(integerDeque.peek()));
} else {
finish();
}
}
}

根据答案更新1//adedd login_flage，但它不起作用

Login_Fragment.java

public class Login_Fragment extends Fragment {
@Nullable
@org.jetbrains.annotations.Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable @org.jetbrains.annotations.Nullable ViewGroup container, @Nullable @org.jetbrains.annotations.Nullable Bundle savedInstanceState) {
if (getActivity() != null && getActivity() instanceof MainActivity)
((MainActivity) getActivity()).bottomNavigationView.setVisibility(View.GONE);
return inflater.inflate(R.layout.login_fragment, container, false);
}
}

更新2：-好的，答案中给出的方法有效，但当我转到上一个片段时，底部导航为所有片段显示，或者我说整个应用程序没有底部导航

Answer 1

您可以在片段中执行以下操作：

BottomNavigationView navBar = getActivity().findViewById(R.id.bottomBar);
navBar.setVisiblity(View.GONE);

或

public class Login_Fragment extends Fragment {
@Nullable
@org.jetbrains.annotations.Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable @org.jetbrains.annotations.Nullable ViewGroup container, @Nullable @org.jetbrains.annotations.Nullable Bundle savedInstanceState) {
if (getActivity() != null && getActivity() instanceof MainActivity)
((MainActivity) getActivity()).bottomNavigationView.setVisibility(View.GONE);
return inflater.inflate(R.layout.login_fragment, container, false);

}
}

Answer 2

你好，我在main activity和rest all中添加了底部导航的布局是片段，现在我有一个登录片段，但我没有想要显示底部导航，而我甚至不想包含分别从底部导航到每个片段，有什么方法吗在那里我可以在一些片段中禁用底部导航，比如登录碎片

因此，您不想在每个片段上处理这一点，而只想在要隐藏BottomNavigationView的片段上处理。

@Ali A.Jalil提供了在访问登录片段时隐藏BottomNavigationView的部分答案；同样，当这个片段在与你隐藏它的片段生命周期相反的方法中被销毁时，你可以再次显示它；即，您已将其隐藏在onCreateView()中，然后需要在onDestroyView()中显示它。

public class Login_Fragment extends Fragment {
@Nullable
@org.jetbrains.annotations.Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable @org.jetbrains.annotations.Nullable ViewGroup container, @Nullable @org.jetbrains.annotations.Nullable Bundle savedInstanceState) {
((MainActivity) requireActivity()).bottomNavigationView.setVisibility(View.GONE);
return inflater.inflate(R.layout.login_fragment, container, false);
}

@Override
public void onDestroyView() {
super.onDestroyView();
((MainActivity) requireActivity()).bottomNavigationView.setVisibility(View.VISIBLE);        
}   
}   

通过这种方式，当您退出登录片段时，您在BottomNavigationView可见性方面具有相同的状态