java - 需要有关抽屉导航过渡的帮助

Question

我设置了一个抽屉导航，首先它在 ocCreate 方法中显示一个 Google map 。我想按抽屉导航菜单中的另一个按钮并更改 map fragment 。

我有一个 Activity_nav.xml 和一个 app_bar_nav.xml，其中包含 content_nav.xml。

我遵循了谷歌地图 API 网站，以便在谷歌开发人员上实现 map 和抽屉导航部分。

现在我被困在这里，因为我不知道如何切换到同一抽屉导航内的另一个 fragment 。

我的 content_nav.xml:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context=".NavActivity"
    tools:showIn="@layout/app_bar_nav">

    <fragment xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:map="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/map"
        android:name="com.google.android.gms.maps.SupportMapFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".NavActivity" />

</android.support.constraint.ConstraintLayout>

我的 onCreate() 方法:

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_nav);

        mAuth = FirebaseAuth.getInstance();

        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) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        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);
        navigationView.setCheckedItem(R.id.nav_home);

        /*Update the UI with user info*/

        FirebaseUser user = mAuth.getCurrentUser();

        TextView email = navigationView.getHeaderView(0).findViewById(R.id.navEmail);
        email.setText(user.getEmail());

        TextView name = navigationView.getHeaderView(0).findViewById(R.id.navUsername);
        name.setText(user.getDisplayName());

        //Setup Map
        SupportMapFragment mapFragment =
                (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }

切换函数:

@SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.
        int id = item.getItemId();

        if (id == R.id.nav_home) {
            // Handle the home action
        } else if (id == R.id.nav_profile) {

        } else if (id == R.id.nav_slideshow) {

        } else if (id == R.id.nav_tools) {

        } else if (id == R.id.nav_share) {

        } else if (id == R.id.nav_logout) {

            mAuth.signOut();
            SharedPreferences sp = getSharedPreferences("Login", MODE_PRIVATE);
            SharedPreferences.Editor Ed = sp.edit();
            Ed.putString("Email", null);
            Ed.putString("Password", null);
            Ed.apply();
            Intent intent = new Intent(getApplicationContext(), MainActivity.class);
            startActivity(intent);

        }

        DrawerLayout drawer = findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }

Answer 1

要在 fragment 之间切换，您的 Activity 布局应具有容器布局:

 <FrameLayout
     android:id="@+id/container"
     android:layout_width="match_parent"
     android:layout_height="match_parent" />

在 Activity 的 onCreate() 方法中，将容器替换为默认 fragment ，即 map fragment :

getSupportFragmentManager().beginTransaction().replace(R.id.container, mapFragment).commit();

然后在 onNavigationItemSelected() 中，将当前 fragment 替换为所选项目的目标 fragment :

Fragment fragment = Fragment.instantiate(this, YourTargetFragment.class.getName().getTitle());
getSupportFragmentManager().beginTransaction().replace(R.id.container, fragment).commit();
setTitle(item.getTitle());