CONTEXT MENU简介

安卓中的上下文菜单是通过长按控件元素触发的,要注意的是每次都会触发onCreateContextMenu方法:

main.xml

<?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:orientation="vertical" > <TextView
android:id="@+id/txt"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="可通过上下文菜单修改背景色"
android:textSize="15pt" /> </LinearLayout>

ContextMenuTest.java

package org.crazyit.ui;

import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView; /**
* Description: <br/>
* site: <a href="http://www.crazyit.org">crazyit.org</a> <br/>
* Copyright (C), 2001-2014, Yeeku.H.Lee <br/>
* This program is protected by copyright laws. <br/>
* Program Name: <br/>
* Date:
*
* @author Yeeku.H.Lee kongyeeku@163.com
* @version 1.0
*/
public class ContextMenuTest extends Activity {
// 为每个菜单定义一个标识
final int MENU1 = 0x111;
final int MENU2 = 0x112;
final int MENU3 = 0x113;
private TextView txt;
int selectedIndex = -1; @Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
txt = (TextView) findViewById(R.id.txt);
// 为文本框注册上下文菜单
registerForContextMenu(txt); // ①
} // 创建上下文菜单时触发该方法
@Override
public void onCreateContextMenu(ContextMenu menu, View source,
ContextMenu.ContextMenuInfo menuInfo) {
menu.add(0, MENU1, 0, "红色");
menu.add(0, MENU2, 0, "绿色");
menu.add(0, MENU3, 0, "蓝色");
// 将三个菜单项设为单选菜单项
menu.setGroupCheckable(0, true, true);
// 设置上下文菜单的标题、图标
menu.setHeaderIcon(R.drawable.tools);
menu.setHeaderTitle("选择背景色");
if (selectedIndex >= 0) {
menu.getItem(selectedIndex).setChecked(true);
}
} // 上下菜单的菜单项被单击时触发该方法。
@Override
public boolean onContextItemSelected(MenuItem mi) {
switch (mi.getItemId()) {
case MENU1:
txt.setBackgroundColor(Color.RED);
selectedIndex = 0;
break;
case MENU2:
txt.setBackgroundColor(Color.GREEN);
selectedIndex = 1;
break;
case MENU3:
txt.setBackgroundColor(Color.BLUE);
selectedIndex = 2;
break;
}
return true;
}
}

截图:

CONTEXT MENU简介

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