android - 打开菜单时不显示抽屉导航图标

Question

下面的代码是我的应用程序中带有工具栏的Navigation Drawer:

    setSupportActionBar(toolbar);
    getSupportActionBar().setDisplayHomeAsUpEnabled(false);
    getSupportActionBar().setHomeButtonEnabled(true);

    drawerToggle = new ActionBarDrawerToggle(this, drawerLayout, toolbar, R.string.empty, R.string.empty) {

        @Override
        public void onDrawerOpened(View drawerView) {
            super.onDrawerOpened(drawerView);
            invalidateOptionsMenu();
        }

        @Override
        public void onDrawerClosed(View drawerView) {
            super.onDrawerClosed(drawerView);
            invalidateOptionsMenu();
        }
    };

    drawerLayout.setDrawerListener(drawerToggle); // Drawer Listener set to the Drawer toggle
    drawerToggle.syncState();


   @Override
    protected void onPostCreate(Bundle savedInstanceState) {
       super.onPostCreate(savedInstanceState);
       drawerToggle.syncState();
   }

   @Override
   public void onConfigurationChanged(Configuration newConfig) {
      super.onConfigurationChanged(newConfig);
      drawerToggle.onConfigurationChanged(newConfig);
   }

ma​​in_activity.xml

 <android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/drawerLayout"
android:layout_width="match_parent"
android:layout_height="match_parent">

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <include layout="@layout/toolbar" />

</LinearLayout>
<ListView
    android:id="@+id/lvMenu"
    android:background="@color/black"
    android:layout_width="310dp"
    android:layout_height="match_parent"
    android:layout_gravity="left"/>
 </android.support.v4.widget.DrawerLayout>

菜单可以正常显示，但是打开菜单时，菜单图标消失如下图:

这是正常状态:

有什么想法吗？

Answer 1

以下代码对我有用:

  drawerLayout.setDrawerListener(drawerToggle); // Drawer Listener set to the Drawer toggle

  drawerLayout.post(new Runnable() {
        @Override
        public void run() {
            // To display hamburger icon in toolbar
            drawerToggle.syncState();
        }
    });

您需要将 drawerToggle.syncState(); 放在 Runnable() 中，并且只在代码中添加一次 drawerToggle.syncState(); .

希望这对您有所帮助。