Action Provider(动作提供者,由ActionProvider类定义)使用自定义的布局来替换动作项,但是它也控制动作项的全部行为。当在动作栏中为菜单项定义动作提供者时,它 不仅使用自定义布局来控制动作项在动作栏中的外观,还控制菜单栏在overflow菜单中显示时的默认事件;另外,它也可以为动作栏或overflow菜单提供子菜单。
1.修改/res/layout包中的main_activity文件,设置背景图片
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/background"
android:orientation="vertical" >
</LinearLayout>
2.在res/layout在新建action_provider.xml文件,定义动作提供者的布局,这里实在LinearLayout中定义了一个按钮控件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
style="?android:attr/actionButtonStyle"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="center"
android:addStatesFromChildren="true"
android:background="?android:attr/actionBarItemBackground"
android:focusable="true" >
<ImageButton
android:id="@+id/button"
android:layout_width="48dip"
android:layout_height="48dip"
android:layout_gravity="center"
android:adjustViewBounds="true"
android:background="@drawable/ic_launcher_settings"
android:contentDescription="@string/settings"
android:scaleType="fitCenter" />
</LinearLayout>
3.在/res/menu文件夹中,新建settings.xml文件,定义菜单项
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android" >
<item
android:id="@+id/menu_item_action_provider_action_bar"
android:actionProviderClass="com.mingrisoft.SettingsActivity$SettingsActionProvider"
android:showAsAction="ifRoom"
android:title="@string/settings"/>
<item
android:id="@+id/menu_item_action_provider_overflow"
android:actionProviderClass="com.mingrisoft.SettingsActivity$SettingsActionProvider"
android:showAsAction="never"
android:title="@string/settings"/>
</menu>
4.新建SettingActivity类,它继承了Activity类。重写onCreate()方法应用布局文件,重写onCreateOptionMenu()方法应用菜单文件,创建SettingsActionProvider内部类实现跳转到系统设置的功能。
public class SettingsActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);// 调用父类方法
setContentView(R.layout.main);// 应用布局文件
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
getMenuInflater().inflate(R.menu.settings, menu);
return true;
}
public static class SettingsActionProvider extends ActionProvider {
private static final Intent settingsIntent = new Intent(Settings.ACTION_SETTINGS);
private Context context;
public SettingsActionProvider(Context context) {
super(context);
this.context = context;
}
@Override
public View onCreateActionView() {
LayoutInflater inflater = LayoutInflater.from(context);
View view = inflater.inflate(R.layout.action_provider, null);
ImageButton button = (ImageButton) view.findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
context.startActivity(settingsIntent);
}
});
return view;
}
@Override
public boolean onPerformDefaultAction() {
context.startActivity(settingsIntent);// 转到设置
return true;
}
}
}