Android之菜單選項Menu(一)

菜單是一個通用的用戶UI組件，在許多應用中都有用到菜單。菜單主要是爲了觸發意圖，跳轉到另外一個頁面。

使用菜單的好處：①形象化菜單結構②可以讓內容和菜單在代碼中分離③允許我們創建一個可選擇的菜單選項適應不同版本的手機

新建工程android_Menu中menu文件夾下的main.xml中

<menu 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"
    tools:context="com.example.android_menu.MainActivity" >

   <item
        android:id="@+id/open"
        android:showAsAction="never"
        android:title="@string/open">
    </item>
    <item
        android:id="@+id/close"
        android:showAsAction="never"
        android:title="@string/close">
    </item>
    <item
        android:id="@+id/save"
        android:showAsAction="never"
        android:title="@string/save"
        android:onClick="saveMessage"
        >
    </item>
    <item
        android:id="@+id/paste"
        android:showAsAction="never"
        android:title="@string/paste">
    </item>

</menu>

strings.xml文件

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">android_Menu</string>
    <string name="hello_world">Hello world!</string>
    <string name="action_settings">Settings</string>
    <string name="open">打開</string>
    <string name="close">關閉</string>
    <string name="save">保存</string>
    <string name="paste">粘貼</string>

</resources>

在layout文件夾下創建open.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <RatingBar
        android:id="@+id/ratingBar1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

創建OpenActivity.java類

package com.example.android_menu;

import android.app.Activity;
import android.os.Bundle;

public class OpenActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.open);
	}
}

在清單文件中的<application>加上創建的類

 <activity android:name=".OpenActivity"></activity>

在MainActivity.java中

package com.example.android_menu;

import android.support.v7.app.ActionBarActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;

public class MainActivity extends ActionBarActivity {

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

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}
	
	//單獨註冊事件監聽
		public void saveMessage(MenuItem item){
			Toast.makeText(MainActivity.this, "--->>+saveMessage", 1).show();
		}


	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		// Handle action bar item clicks here. The action bar will
		// automatically handle clicks on the Home/Up button, so long
		// as you specify a parent activity in AndroidManifest.xml.
		switch (item.getItemId()) {
		case R.id.open:
			Intent intent = new Intent(MainActivity.this, OpenActivity.class);
			startActivity(intent);
			break;

		case R.id.close:
			break;

		case R.id.save:
			break;

		case R.id.paste:
			break;
		}
		return super.onOptionsItemSelected(item);
	}
}

效果圖