android开发教程之wifi开发示例

1、 wifi网卡的状态
wifi网卡的状态信息都以整型变量的形式存放在 android.net.wifi.wifimanager 类中，有以下状态：
wifi_state_disabled
wifi网卡不可用
wifi_state_disabling
wifi网卡正在关闭
wifi_state_enabled
wifi网卡可用
wifi_state_enabling
wifi网卡正在打开
wifi_state_unknown
wifi网卡状态未知
2、 操作wifi 网卡所需的权限
change_network_state
允许应用程序改变网络连接状态
change_wifi_state
允许应用程序改变wifi 连接状态
access_network_state
允许应用程序获取网络的状态信息
access_wifi_state
允许应用程序获得wifi 的状态信息

3、 改变wifi 网卡的状态
对wifi 网卡进行操作需要通过对 wifimanager 对象来进行，获取该对象的方法如下：

wifimanager wifimanager=(wifimanager) context.getsystemservice(service.wifi_service); 

打开wifi 网卡：

wifimanager.setwifienabled(true); 

关闭wifi 网卡

wifimanager.setwifienabled(false); 

获取网卡的当前状态：

wifimanager.getwifistate(); 

示例代码：由于android模拟器不支持wifi操作，所以例子需要在实体手机上运行
androidmanifest.xml

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="me.bym" android:versioncode="1" android:versionname="1.0"> 
    <application android:icon="@drawable/icon" android:label="@string/app_name"> 
        <activity android:name=".wifiactivity" android:label="@string/app_name"> 
            <intent-filter> 
                <action android:name="android.intent.action.main" /> 
                <category android:name="android.intent.category.launcher" /> 
            </intent-filter> 
        </activity> 
    </application> 
    <uses-sdk android:minsdkversion="4" /> 
    <!-- 以下是使用wifi访问网络所需要的权限 --> 
    <uses-permission android:name="android.permission.change_network_state"></uses-permission> 
    <uses-permission android:name="android.permission.change_wifi_state"></uses-permission> 
    <uses-permission android:name="android.permission.access_network_state"></uses-permission> 
    <uses-permission android:name="android.permission.access_wifi_state"></uses-permission> 
</manifest>

activity

package me.bym; 
import android.app.activity; 
import android.content.context; 
import android.net.wifi.wifimanager; 
import android.os.bundle; 
import android.view.view; 
import android.view.view.onclicklistener; 
import android.widget.button; 
import android.widget.toast; 
public class wifiactivity extends activity { 
    private button startwifibutton = null; 
    private button shutdownwifibutton = null; 
    private button checkstatebutton = null; 
    private wifimanager wifimanager = null; 
    private string res = ""; // 用来存放操作结果信息的字符串 
    /** called when the activity is first created. */ 
    @override 
    public void oncreate(bundle savedinstancestate) { 
        super.oncreate(savedinstancestate); 
        setcontentview(r.layout.main); 
        startwifibutton = (button) findviewbyid(r.id.startwifibutton); 
        shutdownwifibutton = (button) findviewbyid(r.id.shutdownwifibutton); 
        checkstatebutton = (button) findviewbyid(r.id.checkstatebutton); 
        startwifibutton.setonclicklistener(new startwifilistener()); 
        shutdownwifibutton.setonclicklistener(new shutdownwifilistener()); 
        checkstatebutton.setonclicklistener(new checkstatelistener()); 
    } 
    class startwifilistener implements onclicklistener { 
        @override 
        public void onclick(view v) { 
            wifimanager = (wifimanager) wifiactivity.this 
                    .getsystemservice(context.wifi_service); 
            if (wifimanager.setwifienabled(true)) { 
                res = "启动wifi服务成功"; 
            } else { 
                res = "启动wifi服务失败"; 
            } 
            toast.maketext(wifiactivity.this, res, toast.length_short).show(); 
        } 
    } 
    class shutdownwifilistener implements onclicklistener { 
        @override 
        public void onclick(view v) { 
            wifimanager = (wifimanager) wifiactivity.this 
                    .getsystemservice(context.wifi_service); 
            if (wifimanager.setwifienabled(false)) { 
                res = "关闭wifi服务成功"; 
            } else { 
                res = "关闭wifi服务失败"; 
            } 
            toast.maketext(wifiactivity.this, res, toast.length_short).show(); 
        } 
    } 
    class checkstatelistener implements onclicklistener { 
        @override 
        public void onclick(view v) { 
            wifimanager = (wifimanager) wifiactivity.this 
                    .getsystemservice(context.wifi_service); 
            switch (wifimanager.getwifistate()) { 
            case wifimanager.wifi_state_disabled: 
                res = "wifi已关闭"; 
                break; 
            case wifimanager.wifi_state_disabling: 
                res = "wifi正在关闭中"; 
                break; 
            case wifimanager.wifi_state_enabled: 
                res = "wifi已启用"; 
                break; 
            case wifimanager.wifi_state_enabling: 
                res = "wifi正在启动中"; 
                break; 
            case wifimanager.wifi_state_unknown: 
                res = "未知wifi状态"; 
                break; 
            } 
            toast.maketext(wifiactivity.this, res, toast.length_short).show(); 
        } 
    } 
}