Android Note - Menu

1. 利用覆寫onCreateOptionsMenu, onOptionsItemSelected這二個方法來建立選單。

2. MainActivity.java

package org.me.android_menu;
package tw.nicky.MenuExample;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;

public class MenuExample extends Activity {
    private TextView describe;

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        setContentView(R.layout.main);
        describe = (TextView) findViewById(R.id.describe);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        menu.add(0, 0, 0, "Help");
        menu.add(0, 1, 1, "Exit");
        return super.onCreateOptionsMenu(menu);
    }
    
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        //According itemId to decide which item user chose
        switch(item.getItemId()) {
            case 0:
                //Show description on the TextView.
                describe.setText("This is a description............");
                break;
            case 1:
                //End
                finish();
                break;
            default:
        }
        return super.onOptionsItemSelected(item);
    }
}

3. main.xml(Layout)

<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">" 
    <TextView
        android:id="@+id/describe"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text=""/>
</LinearLayout>

4. 按下MENU鍵之後出現及點選「說明」之後出現的畫面