Constantly check for wireless network change

Question

I would like to constantly check whether the phone is connected to a specific wireless network. I thought of a service and the SSID of the network of course, but how?

Answer 1

You'll want

<intent-filter>
<action android:name="android.net.wifi.WIFI_STATE_CHANGED"/>
<action android:name="android.net.wifi.STATE_CHANGE"/>
</intent-filter>

In your receiver tag.

Or if you want more control over it, before registering BroadcastReceiver set these up:

final IntentFilter filters = new IntentFilter();
filters.addAction("android.net.wifi.WIFI_STATE_CHANGED");
filters.addAction("android.net.wifi.STATE_CHANGE");
super.registerReceiver(yourReceiver, filters);

WIFI_STATE_CHANGED

Broadcast intent action indicating that Wi-Fi has been enabled, disabled, enabling, disabling, or unknown. One extra provides this state as an int. Another extra provides the previous state, if available.

STATE_CHANGE

Broadcast intent action indicating that the state of Wi-Fi connectivity has changed. One extra provides the new state in the form of a NetworkInfo object. If the new state is CONNECTED, additional extras may provide the BSSID and WifiInfo of the access point. as a String

Also, you'll need to specify the right permissions:

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

Whole Source Code: Download

AndroidManifest.xml

<uses-sdk
    android:minSdkVersion="8"
    android:targetSdkVersion="17" />
<uses-permission android:name="android.permission.INTERNET" />
<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="com.example.temp.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="com.example.temp.MyWiFiStateListener">
        <intent-filter >
            <action android:name="android.net.wifi.STATE_CHANGE"/>
        </intent-filter>
    </receiver>
</application>

MainActivity.java

package com.example.temp;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

}

Broadcast Receiver:

package com.example.temp;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.wifi.WifiInfo;
import android.net.wifi.WifiManager;
import android.util.Log;

public class MyWiFiStateListener extends BroadcastReceiver{

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO Auto-generated method stub
        String action = intent.getAction();
        Log.d("TEMP", action);
        if(action.equals(WifiManager.NETWORK_STATE_CHANGED_ACTION)){
            NetworkInfo info = intent.getParcelableExtra(WifiManager.EXTRA_NETWORK_INFO);
            if(info.getType() == ConnectivityManager.TYPE_WIFI){
                WifiManager myWifiManager = (WifiManager)context.getSystemService(Context.WIFI_SERVICE);
                WifiInfo wifiInfo = myWifiManager.getConnectionInfo();
                Log.d("TEMP","BSSID :: " +  wifiInfo.getBSSID() + "SSID :: " + wifiInfo.getSSID());
            }
        }
    }

}