Android学习笔记16——WIFI操作

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. */@Overridepublic 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 {@Overridepublic 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 {@Overridepublic 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 {@Overridepublic 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();}}}