EnableWifi.java

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

package com.itog_lab.sample.wifi;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.NetworkInfo;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.util.Log;
import android.widget.Toast;

public class EnableWifi extends Activity {
	static final String TAG = "EnableWifi";
    
	WifiManager wifiManager;
	WifiReceiver wifiReceiver;
	Context context;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        context = this.getApplicationContext();

        setContentView(R.layout.main);
        
        wifiManager = (WifiManager)getSystemService(WIFI_SERVICE);
        wifiManager.setWifiEnabled(true);
		wifiReceiver = new WifiReceiver();

		registerReceiver(wifiReceiver, new IntentFilter(WifiManager.NETWORK_STATE_CHANGED_ACTION));
    }
    
    class WifiReceiver extends BroadcastReceiver {

		@Override
		public void onReceive(Context c, Intent i) {
			NetworkInfo info = i.getParcelableExtra(WifiManager.EXTRA_NETWORK_INFO);
			if (info.isConnected()) {
				Toast.makeText(context, "connected", Toast.LENGTH_SHORT).show();
			} else {
				Log.d(TAG, "not connected");
			}
		}
    }
}