ToolBar功能的实现

1.打开res/valus/styles.xml设置Actionbar主题

<resources>

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">   <!--把Actionbar隐藏起来-->
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>

</resources>

2.修改activity——main.xml中的代码

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

</FrameLayout>

3.修改AndroidManifest中的代码

<activity android:name=".MainActivity"
            android:label="FoodTest">    <!--在activity中添加一个label，指定在ToolBar中显示的内容-->

4.在res目录下新建一个drawable文件夹放置所需要的按钮图片资源

5.在res目录下新建一个menu文件夹，并在menu文件下下新建一个toolbar.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <item
        android:id="@+id/backup"
        android:icon="@drawable/ic_backup"
        android:title="Backup"
        app:showAsAction="always" />
    <item
        android:id="@+id/delete"
        android:icon="@drawable/ic_delete"
        android:title="Delete"
        app:showAsAction="ifRoom" />
    <item
        android:id="@+id/setting"
        android:icon="@drawable/ic_settings"
        android:title="Setting"
        app:showAsAction="never" />
</menu>

6.修改MainActivity中的代码：

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar)findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
    }

    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.toolbar, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()){
            case R.id.backup:
                Toast.makeText(this, "backup", Toast.LENGTH_SHORT).show();
                break;
            case R.id.delete:
                Toast.makeText(this, "delete", Toast.LENGTH_SHORT).show();
                break;
            case R.id.setting:
                Toast.makeText(this, "setting", Toast.LENGTH_SHORT).show();
                break;
            default:
        }
        return true;
    }
}