MainActivity如下:

package cc.testwifi;

import android.os.Bundle;

import android.app.Activity;

/**

 * Demo描述:

 * 监听Wifi网络的变化并且获得当前信号强度

 *

 * 参考资料:

 * http://blog.csdn.net/way_ping_li/article/details/8777478

 * Thank you very much

 *

 */

public class MainActivity extends Activity {

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		super.onCreate(savedInstanceState);

		setContentView(R.layout.main);

	}

}

WifiChangeBroadcastReceiver如下:

package cc.testwifi;

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.net.wifi.WifiInfo;

import android.net.wifi.WifiManager;

public class WifiChangeBroadcastReceiver extends BroadcastReceiver {

	private Context mContext;

	@Override

	public void onReceive(Context context, Intent intent) {

		mContext=context;

		System.out.println("Wifi发生变化");

		getWifiInfo();

	}

	private void getWifiInfo() {

        WifiManager wifiManager = (WifiManager) mContext.getSystemService(mContext.WIFI_SERVICE);

        WifiInfo wifiInfo = wifiManager.getConnectionInfo();

        if (wifiInfo.getBSSID() != null) {

        	//wifi名称

            String ssid = wifiInfo.getSSID();

            //wifi信号强度

            int signalLevel = WifiManager.calculateSignalLevel(wifiInfo.getRssi(), 5);

            //wifi速度

            int speed = wifiInfo.getLinkSpeed();

            //wifi速度单位

            String units = WifiInfo.LINK_SPEED_UNITS;

            System.out.println("ssid="+ssid+",signalLevel="+signalLevel+",speed="+speed+",units="+units);

        }

   }

}

AndroidManifest.xml如下:

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="cc.testwifi"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk

        android:minSdkVersion="10"

        android:targetSdkVersion="10" />

    <uses-permission android:name="android.permission.INTERNET"/>

    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>

    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <activity

            android:name="cc.testwifi.MainActivity"

            android:label="@string/app_name" >

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

        <receiver android:name="cc.testwifi.WifiChangeBroadcastReceiver">

            <intent-filter >

                <action android:name="android.net.wifi.RSSI_CHANGED" />

            </intent-filter>

        </receiver>

    </application>

</manifest>

main.xml如下:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    tools:context=".MainActivity" >

    <TextView

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="监听wifi变化并获得当前信号强度"

        android:layout_centerHorizontal="true"

        android:layout_marginTop="50dip"

    />

</RelativeLayout>