import java.util.List; 
import android.app.Activity; 
import android.content.BroadcastReceiver; 
import android.content.Context; 
import android.content.Intent; 
import android.content.IntentFilter; 
import android.net.wifi.ScanResult; 
import android.net.wifi.WifiManager; 
import android.os.Bundle; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.widget.TextView; 

public class WifiTester extends Activity { 
     TextView mainText; 
     WifiManager mainWifi; 
     WifiReceiver receiverWifi; 
     List<ScanResult> wifiList; 
     StringBuilder sb = new StringBuilder(); 

    public void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.main); 
        mainText = (TextView) findViewById(R.id.mainText); 
        mainWifi = (WifiManager) getSystemService(Context.WIFI_SERVICE); 

        receiverWifi = new WifiReceiver(); 
        registerReceiver(receiverWifi, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)); 
        mainWifi.startScan(); 
        mainText.setText("\nStarting Scan...\n"); 
    } 

     public boolean onCreateOptionsMenu(Menu menu) { 
          menu.add(0, 0, 0, "Refresh"); 
          return super.onCreateOptionsMenu(menu); 
     } 

     public boolean onMenuItemSelected(int featureId, MenuItem item) { 
          mainWifi.startScan(); 
          mainText.setText("Starting Scan"); 
          return super.onMenuItemSelected(featureId, item); 
     } 

     protected void onPause() { 
          unregisterReceiver(receiverWifi); 
          super.onPause(); 
     } 

     protected void onResume() { 
          registerReceiver(receiverWifi, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)); 
          super.onResume(); 
     } 

     class WifiReceiver extends BroadcastReceiver { 
          public void onReceive(Context c, Intent intent) { 
               sb = new StringBuilder(); 
               wifiList = mainWifi.getScanResults(); 
             for(int i = 0; i < wifiList.size(); i++){ 
               sb.append(new Integer(i+1).toString() + "."); 
               sb.append((wifiList.get(i)).toString()); 
               sb.append("\n"); 
             } 
             mainText.setText(sb); 
          } 
     } 

}

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"></uses-permission> 
<uses-permission android:name="android.permission.ACCESS_CHECKIN_PROPERTIES"></uses-permission> 
<uses-permission android:name="android.permission.WAKE_LOCK"></uses-permission> 
<uses-permission android:name="android.permission.INTERNET"></uses-permission> 
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE"></uses-permission> 
<uses-permission android:name="android.permission.MODIFY_PHONE_STATE"></uses-permission>