android開發教程之wifi開發示例

1、 WIFI網卡的狀態
WIFI網卡的狀態信息都以整型變量的形式存放在 android.net.wifi.WifiManager 類中，有以下狀態：
WIFI_STATE_DISABLED
WIFI網卡不可用
WIFI_STATE_DISABLING
WIFI網卡正在關閉
WIFI_STATE_ENABLED
WIFI網卡可用
WIFI_STATE_ENABLING
WIFI網卡正在打開
WIFI_STATE_UNKNOWN
WIFI網卡狀態未知
2、 操作WIFI 網卡所需的權限
CHANGE_NETWORK_STATE
允許應用程序改變網絡連接狀態
CHANGE_WIFI_STATE
允許應用程序改變WIFI 連接狀態
ACCESS_NETWORK_STATE
允許應用程序獲取網絡的狀態信息
ACCESS_WIFI_STATE
允許應用程序獲得WIFI 的狀態信息

3、 改變WIFI 網卡的狀態
對WIFI 網卡進行操作需要通過對 WifiManager 對象來進行，獲取該對象的方法如下：
復制代碼 代碼如下:
WifiManager wifiManager=(WifiManager) Context.getSystemService(Service.WIFI_SERVICE); 

打開WIFI 網卡：
復制代碼 代碼如下:
wifiManager.setWifiEnabled(true); 

關閉WIFI 網卡
復制代碼 代碼如下:
wifiManager.setWifiEnabled(false); 

獲取網卡的當前狀態：
復制代碼 代碼如下:
wifiManager.getWifiState(); 

示例代碼：由於Android模擬器不支持wifi操作，所以例子需要在實體手機上運行
AndroidManifest.xml
復制代碼 代碼如下:
<?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訪問網絡所需要的權限 --> 
    <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
復制代碼 代碼如下:
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 = ""; // 用來存放操作結果信息的字符串 
    /** 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 = "啟動wifi服務成功"; 
            } else { 
                res = "啟動wifi服務失敗"; 
            } 
            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 = "關閉wifi服務成功"; 
            } else { 
                res = "關閉wifi服務失敗"; 
            } 
            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已關閉"; 
                break; 
            case WifiManager.WIFI_STATE_DISABLING: 
                res = "WIFI正在關閉中"; 
                break; 
            case WifiManager.WIFI_STATE_ENABLED: 
                res = "WIFI已啟用"; 
                break; 
            case WifiManager.WIFI_STATE_ENABLING: 
                res = "WIFI正在啟動中"; 
                break; 
            case WifiManager.WIFI_STATE_UNKNOWN: 
                res = "未知WIFI狀態"; 
                break; 
            } 
            Toast.makeText(WifiActivity.this, res, Toast.LENGTH_SHORT).show(); 
        } 
    } 
}