我有一个 Android 应用程序 (Java),它使用导航组件来设置底部导航。该应用程序由一个活动(主)组成,其他所有内容都以片段形式加载。
这个想法是让启动屏幕启动并检查用户是否登录。如果用户登录,则加载主屏幕并且底部导航(之前隐藏)变得可见。
底部导航由 3 个选项卡组成。
但是,当用户登录时,它可以是两种类型的用户之一。如果他是订阅者,他将可以访问该应用程序的所有部分。但是,如果用户是访客,他将只能访问两个部分。在这种情况下,我希望有一个不同的底部导航菜单,只需 2 个选项卡即可可见。
如果主底部导航已在主活动中分配,如何根据用户类型替换底部导航?
这是代码中的主要活动:
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FragmentManager supportFragmentManager = getSupportFragmentManager();
NavHostFragment navHostFragment = (NavHostFragment) supportFragmentManager.findFragmentById(R.id.nav_host_fragment);
NavController navController = navHostFragment.getNavController();
AppBarConfiguration appBarConfiguration = new AppBarConfiguration.Builder(R.id.homeFragment, R.id.libraryFragment, R.id.searchFragment, R.id.myStuffFragment).build();
NavigationUI.setupWithNavController(toolbar, navController, appBarConfiguration);
BottomNavigationView bottomNav = findViewById(R.id.bottom_nav);
NavigationUI.setupWithNavController(bottomNav, navController);
navController.addOnDestinationChangedListener(new NavController.OnDestinationChangedListener() {
@Override
public void onDestinationChanged(@NonNull NavController controller, @NonNull NavDestination destination, @Nullable Bundle arguments) {
if (destination.getId() == R.id.splashScreenFragment || destination.getId() == R.id.welcomeFragment || destination.getId() == R.id.signInFragment) {
toolbar.setVisibility(View.GONE);
bottomNav.setVisibility(View.GONE);
} else if (destination.getId() == R.id.audioPlayerFragment) {
bottomNav.setVisibility(View.GONE);
} else {
toolbar.setVisibility(View.VISIBLE);
bottomNav.setVisibility(View.VISIBLE);
}
}
});
这是代码中的启动画面片段(这是 nav_graph 中的 startDestination):
public class SplashScreenFragment extends Fragment {
private static final String TAG = "SplashScreenFragment";
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_splash_screen, container, false);
return v;
}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
SharedPreferences getSharedData = this.getActivity().getSharedPreferences("AppTitle", Context.MODE_PRIVATE);
Boolean loggedIn = getSharedData.getBoolean("isUserLoggedIn", false);
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
if (!loggedIn) {
Navigation.findNavController(view).navigate(R.id.action_splashScreenFragment_to_welcomeFragment);
} else {
Navigation.findNavController(view).navigate(R.id.action_splashScreenFragment_to_homeFragment);
}
}
}, 2000);
}