android - 我正在尝试使用 fragment 创建 BottomNavigationView，我想在主布局中使用 fragment

Question

它可以成功构建并运行，但在虚拟设备中已停止。 这是我在 fragment 中主要布局的代码:

public class BlankFragment14 extends Fragment {

@Override
public View onCreateView( LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState ) {

        return inflater.inflate(R.layout.fragment_blank_fragment14, container, false);

    }


        @Override
        public void onCreate( @Nullable Bundle savedInstanceState ) {
            super.onCreate(savedInstanceState);

            BottomNavigationView bottomNav = getView( ).findViewById(R.id.bottom_navigation);
            BottomNavigationView.OnNavigationItemSelectedListener navListener = null;
            bottomNav.setOnNavigationItemSelectedListener(navListener);

            getFragmentManager( ).beginTransaction( ).replace(R.id.fragment_container1, new ProfileFragment( )).commit( );

            navListener = new BottomNavigationView.OnNavigationItemSelectedListener( ) {
                @Override
                public boolean onNavigationItemSelected( @NonNull MenuItem menuItem ) {
                    Fragment selectedFragment = null;

                    switch (menuItem.getItemId( )) {
                        case R.id.nav_profile1:
                            selectedFragment = new ProfileFragment( );
                            break;
                        case R.id.nav_appointment1:
                            selectedFragment = new AppointmentFragment( );
                            break;
                        case R.id.nav_patientdata1:
                            selectedFragment = new PatientdataFragment( );
                            break;
                    }
                    getFragmentManager( ).beginTransaction( ).replace(R.id.fragment_container1, selectedFragment).commit( );

                    return true;
                }
            };


        }


    }

我不知道可以工作吗？或者我必须使用 Activity 作为主要布局。

Answer 1

使用 Navigation 组件实现 BottomNavigationView。您的 MainActivity 必须具有 NavHostFragment，它可以显示其他 fragment 目标。在 MainActivity 的 onCreate 中 如下所示设置 NavController:

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Toolbar myToolbar = (Toolbar) findViewById(R.id.toolbar1);
    setSupportActionBar(myToolbar);
    BottomNavigationView navView = findViewById(R.id.nav_view);
    // Passing each menu ID as a set of Ids because each
    // menu should be considered as top level destinations.
    AppBarConfiguration appBarConfiguration = new AppBarConfiguration.Builder(
            R.id.navigation_home, R.id.navigation_dashboard, R.id.navigation_notifications)
            .build();
    NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
   //NavigationUI.setupActionBarWithNavController(this, navController, appBarConfiguration);
    NavigationUI.setupWithNavController(navView, navController);
}