ActionBar右边菜单按钮的添加

在res目录下新建文件夹menu，存放men.xml文件

menu.xml

<menu
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <item
        android:id="@+id/action_menu"
        android:title="选项卡"
        android:icon="@android:drawable/ic_input_add"
        app:showAsAction="ifRoom">

        <menu>
            <item
                android:id="@+id/action_1"
                android:icon="@android:drawable/ic_menu_mapmode"
                android:title="模式1"
                app:showAsAction="ifRoom"/>
            <item
                android:id="@+id/action_2"
                android:icon="@android:drawable/btn_star_big_off"
                android:title="模式2"
                app:showAsAction="ifRoom"/>
            <item
                android:id="@+id/action_3"
                android:icon="@android:drawable/btn_star_big_off"
                android:title="模式3"
                app:showAsAction="ifRoom"/>
            <item
                android:id="@+id/action_4"
                android:icon="@android:drawable/btn_star_big_off"
                android:title="模式4"
                app:showAsAction="ifRoom"/>
            <item
                android:id="@+id/action_5"
                android:icon="@android:drawable/btn_star_big_off"
                android:title="模式5"
                app:showAsAction="ifRoom"/>
            <item
                android:id="@+id/action_6"
                android:icon="@android:drawable/ic_dialog_map"
                android:title="交通线"
                app:showAsAction="ifRoom"/>
        </menu>

    </item>
</menu>

MainActivity.java

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.action_1:
                break;
            case R.id.action_2:
                break;
            case R.id.action_3:
                break;
            case R.id.action_4:
                break;
            case R.id.action_5:break;
            case R.id.action_6:break;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        getMenuInflater().inflate(R.menu.menu, menu);
        return super.onCreateOptionsMenu(menu);
    }
}

运行效果图：