Navigatation Drawer

先載入dependency

dependencies {
implementation 'com.google.android.material:material:1.0.0'
}

設計activity_main.xml最外框是DrawerLayer，包覆著LinearLayout。LinearLayout 為 一 Action Bar + Fragment 要切換的區域

<androidx.drawerlayout.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    
    <!-- This LinearLayout represents the contents of the screen  -->
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
<!-- The ActionBar displayed at the top -->
        <include
            layout="@layout/toolbar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />
<!-- The main content view where fragments are loaded -->
        <FrameLayout
            android:id="@+id/flContent"
            app:layout_behavior="@string/appbar_scrolling_view_behavior"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />
    </LinearLayout>
<!-- The navigation drawer that comes from the left -->
    <!-- Note that `android:layout_gravity` needs to be set to 'start' -->
    <com.google.android.material.navigation.NavigationView
        android:id="@+id/nvView"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:background="@android:color/white"
        app:headerLayout="@layout/nav_header"
        app:menu="@menu/drawer_view" />
</androidx.drawerlayout.widget.DrawerLayout

透過app:headerLayout="@layout/nav_header" 來加入header圖像的部分在runtime 時期將會inflat為

NavigationView navigationView = (NavigationView) findViewById(R.id.nvView);
View headerLayout = navigationView.inflateHeaderView(R.layout.nav_header);
ImageView ivHeaderPhoto = headerLayout.findViewById(R.id.imageView);

app:menu="@menu/drawer_view" />來加入選單內容

設計ToolBar

<?xml version="1.0" encoding="utf-8"?>
<androidx.appcompat.widget.Toolbar
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/toolbar"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:fitsSystemWindows="true"
android:minHeight="?attr/actionBarSize"
app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
android:background="?attr/colorPrimaryDark">
</androidx.appcompat.widget.Toolbar>

在styles.xml 中調整ActionBar 為<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">

如果忘了調整styles.xml ， 會引發 error

java.lang.RuntimeException: Unable to start activity ComponentInfo{tw.com.ian.mydrawer/tw.com.ian.mydrawer.MainActivity}: java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead.

設計header

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="192dp"
android:background="?attr/colorPrimaryDark"
android:padding="16dp"
android:theme="@style/ThemeOverlay.AppCompat.Dark"
android:orientation="vertical"
android:gravity="bottom">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/running"
/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="史艷文"
android:textColor="@android:color/white"
android:textAppearance="@style/TextAppearance.AppCompat.Body1"/>
</LinearLayout>

設計menu

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<group android:checkableBehavior="single">
<item
android:id="@+id/medical_fragment"
android:icon="@drawable/ic_one"
android:title="醫學院" />
<item
android:id="@+id/chat_fragment"
android:icon="@drawable/ic_two"
android:title="聊天室" />
<item
android:id="@+id/game_fragment"
android:icon="@drawable/ic_three"
android:title="遊戲室" />
<item android:title="其他">
<menu>
<group android:checkableBehavior="single">
<item
android:title="設定" />
<item
android:title="登入" />
</group>
</menu>
</item>
</group>
</menu>

到此，layout 設計完成。接下來撰寫activity的內容

第4行的toolbar 就是之前設計的toolbar

10~16行綁定DrawerLayout 與Toolbar

19–58 行設定menu 被觸發時要執行的動作

1. protected void onCreate(Bundle savedInstanceState) {
2. super.onCreate(savedInstanceState);
3. setContentView(R.layout.activity_main);
4. toolbar = (Toolbar) findViewById(R.id.toolbar);
5. setSupportActionBar(toolbar);
6. // This will display an Up icon (<-), we will replace it with hamburger later
7. getSupportActionBar().setDisplayHomeAsUpEnabled(true);
8. // Find our drawer view
9. drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
10. toggle = new ActionBarDrawerToggle(this, drawer, toolbar, R.string.drawer_open, R.string.drawer_close);
11. toggle.setDrawerIndicatorEnabled(true);
12. toggle.syncState();
13. // Tie DrawerLayout events to the ActionBarToggle
14. drawer.addDrawerListener(toggle);
15. navigationView = (NavigationView) findViewById(R.id.nvView);
16. navigationView.setNavigationItemSelectedListener(
17. new NavigationView.OnNavigationItemSelectedListener() {
18. @Override
19. public boolean onNavigationItemSelected(MenuItem menuItem) {
20. Fragment fragment = null;
21. Class fragmentClass;
22. switch(menuItem.getItemId()) {
23. case R.id.medical_fragment:
24. fragmentClass = MedicalFragment.class;
25. break;
26. case R.id.chat_fragment:
27. fragmentClass = ChatFragment.class;
28. break;
29. case R.id.game_fragment:
30. fragmentClass = GameFragment.class;
31. break;
32. default:
33. fragmentClass = MedicalFragment.class;
34. }
35. try {
36. fragment = (Fragment) fragmentClass.newInstance();
37. } catch (Exception e) {
38. e.printStackTrace();
39. }
40. // Insert the fragment by replacing any existing fragment
41. FragmentManager fragmentManager = getSupportFragmentManager();
42. fragmentManager.beginTransaction().replace(R.id.flContent, fragment).commit();
43. // Highlight the selected item has been done by NavigationView
44. menuItem.setChecked(true);
45. // Set action bar title
46. setTitle(menuItem.getTitle());
47. // Close the navigation drawer
48. drawer.closeDrawers();
49. return true;
50. }
51. });
52. }