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. */ @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(); } } }