Android DrawerLayout實現NavigationView不記住上次所選選項

Android DrawLayout和NavigationView優化

android自帶DrawLayout和NavigationView，使得我們可以將一些菜單隱藏起來，而不是放置在主屏幕上，然後可以通過滑動的方式將菜單顯示出來，這種方式既節省了屏幕空間，又實現了非常好的動畫效果，使用起來也很方便。之前使用的時候，在navigation上選中某個item後，退出drawLayout，默認會記住上一個的選項，感覺不是很好，後來實現了非記憶功能。

先看效果圖吧。

下面直接上步驟和相關代碼。

1.build.gradle引用兩個依賴

 implementation 'de.hdodenhof:circleimageview:2.1.0'
 implementation 'com.android.support:design:28.0.0'

2.activity_main.xml:只是簡單地放置一個CircleImageView

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/DrawerLayout"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:focusable="true"
        android:clickable="true"
        android:focusableInTouchMode="true"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
    <android.support.design.widget.CoordinatorLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"

    >
            <android.support.constraint.ConstraintLayout
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:focusable="true"
                    android:focusableInTouchMode="true"
                    tools:context=".Acitivity.WorksIndexActivity">

                <de.hdodenhof.circleimageview.CircleImageView
                        android:layout_width="40dp"
                        android:layout_height="40dp"
                        android:src="@mipmap/image0"
                        android:id="@+id/avatar"
                        app:layout_constraintTop_toTopOf="parent" android:layout_marginTop="16dp"
                        app:layout_constraintStart_toStartOf="parent" android:layout_marginStart="16dp"
                />


            </android.support.constraint.ConstraintLayout>


    </android.support.design.widget.CoordinatorLayout>

    <android.support.design.widget.NavigationView android:layout_width="match_parent"
                                                  android:layout_height="match_parent"
                                                  android:id="@+id/nav_view"
                                                  android:layout_gravity="start"
                                                  app:menu="@menu/nav_menu"
                                                  app:headerLayout="@layout/nav_header"/>
</android.support.v4.widget.DrawerLayout>

3.在res文件夾下的layout新建nav_header.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">
    <ImageView
            android:layout_width="0dp"
            android:layout_height="200dp"
            android:src="@mipmap/image2"
            android:id="@+id/imageView7" app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent"
            android:scaleType="fitXY" app:layout_constraintHorizontal_bias="0.0"/>
    <de.hdodenhof.circleimageview.CircleImageView
            android:layout_width="80dp"
            android:layout_height="80dp"
            android:src="@mipmap/image0"
            android:id="@+id/imageView8" app:layout_constraintStart_toStartOf="@+id/imageView7"
            android:layout_marginStart="32dp" android:layout_marginBottom="32dp"
            app:layout_constraintBottom_toBottomOf="@+id/imageView7"/>
    <TextView
            android:text="ID:1106488127"
            android:textSize="12dp"
            android:textColor="@color/white"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/textView9" app:layout_constraintStart_toEndOf="@+id/imageView8"
            android:layout_marginStart="24dp" app:layout_constraintTop_toTopOf="@+id/imageView8"
            android:layout_marginTop="30dp"/>
    <TextView
            android:text="zoom"
            android:textSize="20dp"
            android:textColor="@color/white"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/textView11" android:layout_marginStart="24dp"
            app:layout_constraintStart_toEndOf="@+id/imageView8" android:layout_marginBottom="8dp"
            app:layout_constraintBottom_toTopOf="@+id/textView9"/>

</android.support.constraint.ConstraintLayout>

4.在res文件夾下新建文件夾menu，menu裏面建立文件nav_menu.xml,注意這裏多了個選項id爲menu_none,title爲空，並顯示不可見，這裏是退出drawerlayout後不記憶上次選擇的關鍵，通過選擇menu_none實現“曲線救國”

<?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/index"
              android:icon="@mipmap/home"
              android:title="主頁"/>
        <item android:id="@+id/discover"
              android:icon="@mipmap/faxian"
              android:title="發現"/>
        <item android:id="@+id/love"
              android:icon="@mipmap/aixin"
              android:title="我喜歡的作品"/>
        <item android:id="@+id/attention"
              android:icon="@mipmap/guanzhu"
              android:title="關注"/>
        <item android:id="@+id/info"
              android:icon="@mipmap/wodexiaoxi"
              android:title="我的信息"/>
        <item android:id="@+id/setting"
              android:icon="@mipmap/shezhi"
              android:title="設置"/>
        <item android:id="@+id/menu_none"
              android:title=""
              android:visible="false"/>

    </group>
</menu>

5.MainActivity實現，給drawerLayout增加監聽事件。

public class MainActivity extends AppCompatActivity {

    private DrawerLayout drawerLayout;
    private NavigationView navigationView;

    private float CurrentSlideOffset = 0.0f;
    private Runnable ShouldHandleMenuClicked = null;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        drawerLayout = findViewById(R.id.DrawerLayout);
        navigationView = findViewById(R.id.nav_view);

        drawerLayout.addDrawerListener(new DrawerLayout.SimpleDrawerListener() {
            @Override
            public void onDrawerSlide(View drawerView, float slideOffset) {
                super.onDrawerSlide(drawerView, slideOffset);
                if (CurrentSlideOffset > slideOffset && slideOffset < 0.015f && ShouldHandleMenuClicked != null) {
                    ShouldHandleMenuClicked.run();
                    ShouldHandleMenuClicked = null;
                    runOnUiThread(() -> {
                        navigationView.setCheckedItem(R.id.menu_none);
                    });
                }
                CurrentSlideOffset = slideOffset;
            }
        });

        ImageView avatar = findViewById(R.id.avatar);
        avatar.setOnClickListener(v -> drawerLayout.openDrawer(GravityCompat.START));

        navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
                switch (menuItem.getItemId()) {
                    case R.id.index:
                        ShouldHandleMenuClicked = () -> {
                            Toast.makeText(MainActivity.this,"你點擊了主頁",Toast.LENGTH_SHORT).show();
                        };
                        break;
                    case R.id.discover:
                        ShouldHandleMenuClicked = () -> {
                            Toast.makeText(MainActivity.this,"你點擊了發現",Toast.LENGTH_SHORT).show();
                        };
                        break;
                    case R.id.love:
                        ShouldHandleMenuClicked = () -> {
                            Toast.makeText(MainActivity.this,"你點擊了我喜歡的作品",Toast.LENGTH_SHORT).show();
                        };
                        break;
                    case R.id.attention:
                        ShouldHandleMenuClicked = () -> {
                            Toast.makeText(MainActivity.this,"你點擊了關注",Toast.LENGTH_SHORT).show();
                        };
                        break;
                    case R.id.info:
                        ShouldHandleMenuClicked = () -> {
                            Toast.makeText(MainActivity.this,"你點擊了我的信息",Toast.LENGTH_SHORT).show();
                        };
                        break;
                    case R.id.setting:
                        ShouldHandleMenuClicked = () -> {
                            Toast.makeText(MainActivity.this,"你點擊了設置",Toast.LENGTH_SHORT).show();
                        };
                        break;

                }
                drawerLayout.closeDrawers();
                return true;
            }
        });
    }
}

一些圖標資源和用到的一個color資源就沒有寫出來了。