android UI组件----菜单

android中菜单分为三种，分别是，options menu 选项菜单，sub menu 子菜单，context menu 上下文菜单。下面分别举例演示这三种菜单：

新建一个android project，

options menu，第一种方法，通过xml定义选项菜单，在res文件夹中新建一个名为menu的文件夹，在其内新建一个options_menu.xml的文件：

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android" >

    <item
        android:id="@+id/newFile"
        android:icon="@drawable/ic_launcher"
        android:title="@string/newFile"
        />
    <!-- android:icon 设置菜单选项的图标
	android：title 设置菜单选项的标题 -->
    <item 
        android:id="@+id/exit"
        android:icon="@drawable/ic_launcher"
        android:title="@string/exit"
        />

</menu>

在MenuTestActivity1中：

package cn.sword.activity;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.MenuItem.OnMenuItemClickListener;
import android.widget.Toast;

public class MenuTestActivity1 extends Activity implements OnMenuItemClickListener{
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
    }

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		MenuInflater inflater = this.getMenuInflater();
		inflater.inflate(R.menu.options_menu, menu);
		//第一种响应菜单点击事件的方法
		//为每一个菜单选项添加监听事件
		//在覆盖的onMenuItemClick（）方法中判断并触发监听事件
		for(int i=0;i<menu.size();i++){
			menu.getItem(i).setOnMenuItemClickListener((OnMenuItemClickListener) this);
		}

		return super.onCreateOptionsMenu(menu);
	}

	/*第二种响应菜单点击事件的方法 覆盖onOptionsItemSelected（）方法
	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		switch(item.getItemId()){
			case R.id.newFile:
				Toast.makeText(this,"new File", Toast.LENGTH_LONG).show();
				break;
			case R.id.exit:
				this.finish();//退出程序
				break;
		}
		
		return super.onOptionsItemSelected(item);
	}*/
	
	public boolean onMenuItemClick(MenuItem item){
		switch(item.getItemId()){
		case R.id.newFile:
			Toast.makeText(this, "new File", Toast.LENGTH_LONG).show();
			break;
		case R.id.exit:
			this.finish();
		}
		
		return false;
	}
    
}

在模拟器中点击Menu键效果：

options menu，第二种方法，动态添加删除菜单

在MenuTestActivity2中：

package cn.class3g.activity;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.Toast;

public class MenuTestActivity2 extends Activity {
<span style="white-space: pre;">	</span>//定义菜单项
	private static final int SAVE=1;
	private static final int SAVE_AS = SAVE+1;
	private static final int DELETE = SAVE+2;
	//声明一个menu对象
	Menu menu = null;

	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
	}

	public boolean onCreateOptionsMenu(Menu menu) {
		MenuInflater inflater = this.getMenuInflater();
		inflater.inflate(R.menu.options_menu, menu);
		
		//向菜单中添加菜单项
		menu.add(1, SAVE, 1, "保存");
		menu.add(1,SAVE_AS, 2, "另存为");
		menu.add(1,DELETE, 3, "删除保存");
		//设置菜单项的图标
		menu.findItem(SAVE).setIcon(R.drawable.ic_launcher);	
		
		this.menu = menu;

		return true;
	}
	
<span style="white-space: pre;">	</span>//动态的修改菜单title	
	int i=1;
	public boolean onPrepareOptionsMenu(Menu menu) {
		MenuItem item = menu.findItem(SAVE_AS);
		item.setTitle(item.getTitle() + "" + i);

		i++;
		return super.onPrepareOptionsMenu(menu);
	}
<span style="white-space: pre;">	</span>//响应菜单单击事件
	public boolean onOptionsItemSelected(MenuItem item) {
		switch (item.getItemId()) {
		case R.id.newFile:

			Toast.makeText(this, "new file", Toast.LENGTH_LONG).show();//利用Toast弹出文本信息
			break;
		case R.id.exit:
			// Toast.makeText(this, "exit", Toast.LENGTH_LONG).show();
			this.finish();//关闭Activity
			break;
		case DELETE:<pre class="html" name="code"><span style="white-space: pre;">			</span>//menu.removeGroup(1);//删除一组菜单</pre>

menu.removeItem(SAVE_AS);//删除一个菜单break;}return true;}}

sub menu 子菜单

利用xml定义菜单参考options menu。

动态的添加子菜单：

在MenuTestActivity3中：

package cn.sword.activity;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.SubMenu;
import android.widget.Toast;

public class MenuTestActivity3 extends Activity {
<span style="white-space: pre;">	</span>//定义菜单项
	private static final int SUBMENU = 10;
	private static final int SUBITEM1 = SUBMENU+1;
	private static final int SUBITEM2 = SUBMENU+2;
	private static final int SUBITEM3 = SUBMENU+3;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		this.setContentView(R.layout.main);
	}
	
	public boolean onCreateOptionsMenu(Menu menu){
		MenuInflater inflater = this.getMenuInflater();
		inflater.inflate(R.menu.sub_menu, menu);
		//添加子菜单
		SubMenu subMenu = menu.addSubMenu(1,SUBMENU,1,"子菜单");
		subMenu.add(20,SUBITEM1,1,"subitem1");
		subMenu.add(20,SUBITEM2,2,"subitem2");
		subMenu.add(30,SUBITEM3,3,"subitem3");
		
		subMenu.setGroupCheckable(20, true, false);
		//第二个参数是否可选
		//当第三个参数为true时为这组菜单为互斥（单选）菜单
		//当第三个参数为false时为组菜单为复选菜单
		
		MenuItem item = subMenu.getItem(0);
		//item.setCheckable(false);//设置该项菜单为单选或复选
		item.setChecked(true);//设置菜单的默认选项

		//subMenu.getItem(0).setCheckable(true);
		
		return true;
	}
	
	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		switch(item.getItemId()){
			case R.id.menuitem1:
				Toast.makeText(this,"menuitem1", Toast.LENGTH_LONG).show();
				break;
			case R.id.menuitem2:
				Toast.makeText(this,"menuitem2", Toast.LENGTH_LONG).show();
				break;
			case R.id.subitem1:
				Toast.makeText(this,"subitem1", Toast.LENGTH_LONG).show();
				break;
			case R.id.subitem2:
				Toast.makeText(this,"subitem2", Toast.LENGTH_LONG).show();
				break;
			case SUBITEM1:
				Toast.makeText(this,"SUBITEM1", Toast.LENGTH_LONG).show();
				break;
			case SUBITEM2:
				Toast.makeText(this,"SUBITEM2", Toast.LENGTH_LONG).show();
				//this.finish();//退出程序
				break;
		}
		
		return super.onOptionsItemSelected(item);
	}
}

在模拟器中点击Menu键：

单击子菜单：

context menu 上下文菜单：context menu需要绑定在TextView上并在其上按2s后显示。

在MenuTestActivity4中：

package cn.sword.activity;

import android.app.Activity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

public class MenuTestActivity4 extends Activity {
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		this.setContentView(R.layout.main);
		//将上下文菜单绑定到TextView上
		TextView tv = (TextView) this.findViewById(R.id.textView);
		this.registerForContextMenu(tv);
	}

	@Override
	public boolean onContextItemSelected(MenuItem item) {
		switch(item.getItemId()){
			case R.id.subitem1:
				Toast.makeText(this, "subitem1",Toast.LENGTH_LONG).show();
				break;
			case R.id.subitem2:
				Toast.makeText(this, "subitem2",Toast.LENGTH_LONG).show();
				break;
		}
		return super.onContextItemSelected(item);
	}

	//每次上下文菜单显示都会调用
	public void onCreateContextMenu(ContextMenu menu, View v,
			ContextMenuInfo menuInfo) {
		
		MenuInflater inflater = this.getMenuInflater();
		inflater.inflate(R.menu.sub_menu, menu);
		super.onCreateContextMenu(menu, v, menuInfo);
	}
}

运行模拟器，点击文本内容2s后：