Question

我正在使用带有BottomNavigationView和单个活动的Android体系结构导航组件设计一个应用程序。第一个选项卡是默认选项卡，应显示时间表。要加载计划表，用户必须登录，因此我试图在MainActivity.java中使用以下代码实现条件导航：

 @Override
protected void onCreate(Bundle savedInstanceState) {
    //setTheme(android.R.style.Theme );
    super.onCreate(savedInstanceState);
    mContext = (Context) this;
    setContentView(R.layout.activity_main);
    mViewModel = ViewModelProviders.of(this).get(MainViewModel.class);

    setupNavigation();
}

private void setupNavigation()
{
    mToolbar = findViewById(R.id.toolbar);
    mBottomTabs = findViewById(R.id.bottom_tabs);
    setSupportActionBar(mToolbar);
    mNavController = Navigation.findNavController(this, R.id.content);
    NavigationUI.setupWithNavController(mBottomTabs, mNavController);

    AppBarConfiguration appBarConfiguration = new AppBarConfiguration.Builder(             R.id.schedFrag, R.id.studyPlanFragment).build();

    NavigationUI.setupActionBarWithNavController(this, mNavController, appBarConfiguration);

    mNavController.addOnDestinationChangedListener(
            new NavController.OnDestinationChangedListener()
            {
                @Override
                public void onDestinationChanged(@NonNull NavController controller, @NonNull NavDestination destination, @Nullable Bundle arguments) {
                    int id = destination.getId();
                    if (mViewModel.m_auth.isUserLoggedIn(mContext))
                    {
                        if(mViewModel.isDataLoaded(id))
                            mNavController.navigate(destination.getId());
                        else //data not loaded yet
                        {
                            mViewModel.loadData(id, MainActivity.this);
                            Bundle args = new Bundle();
                            args.putInt(MainViewModel.ARGS_NEXT_SCREEN, destination.getId());
                            mNavController.navigate(R.id.loadFrag, args);
                        }
                    }
                    else
                    {
                        mViewModel.m_LoginFragmentNextScreen = id;
                        int nextDestination =R.id.act_schFrag_to_logFrag;
                        mNavController.navigate(nextDestination);
                    }
                }
            });
}

主要活动布局：

<?xml version="1.0" encoding="utf-8"?>

<androidx.appcompat.widget.Toolbar
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:background="@color/colorPrimary"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    android:theme="@style/ThemeOverlay.AppCompat.Dark" />

<fragment
    android:id="@+id/content"
    android:name="androidx.navigation.fragment.NavHostFragment"
    android:layout_width="0dp"
    android:layout_height="0dp"
    app:defaultNavHost="true"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    app:layout_constraintBottom_toTopOf="@+id/bottom_tabs"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.587"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/toolbar"
    app:navGraph="@navigation/nav_graph" />

<com.google.android.material.bottomnavigation.BottomNavigationView
    android:id="@+id/bottom_tabs"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_marginStart="0dp"
    android:layout_marginEnd="0dp"
    android:background="@color/colorPrimary"
    app:itemTextColor="@color/bottom_nav_color"
    app:itemIconTint="@color/bottom_nav_color"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:menu="@menu/tabs_navigation" />

我的导航图是这样的：

导航图代码如下：

<?xml version="1.0" encoding="utf-8"?>

<fragment
    android:id="@+id/logFrag"
    android:name="com.myapp.Fragments.LoginFragment"
    android:label="@string/title_login"
    tools:layout="@layout/login_fragment" >
    <action
        android:id="@+id/act_logFrag_to_loadFrag"
        app:destination="@id/loadFrag" />
</fragment>

<fragment
    android:id="@+id/schedFrag"
    android:name="com.myapp.Fragments.ScheduleFragment"
    android:label="@string/hs_title_schedule"
    tools:layout="@layout/fragment_schedule" >
    <action
        android:id="@+id/act_schFrag_to_logFrag"
        app:destination="@id/logFrag"
        app:popUpTo="@+id/schedFrag"
        app:popUpToInclusive="true"
        />
    <action
        android:id="@+id/action_scheduleFragment_to_loadingFragment"
        app:destination="@id/loadFrag" />
</fragment>

<fragment
    android:id="@+id/loadFrag"
    android:name="com.myapp.Fragments.LoadingFragment"
    android:label="fragment_loading"
    tools:layout="@layout/fragment_loading" >
    <argument
        android:name="FragmentType"
        app:argType="integer" />
</fragment>

我的问题是：

我应该像现在那样使用专用片段来实现加载进度，还是应该以某种方式在SchedFragment中显示进度（可能是通过仅设置单个进度来设置单独的片段布局），然后通过切换使所有数据字段可见到包含数据字段的布局中？

导航体系结构组件-加载屏幕

0 个答案: