当wifi或3g网络状态改变时，BroadcastReceiver

Question

I have an app which updates the database whenever the phone is connected to WiFi. I have implemented a Service and BroadcastReceiver which will run the Service (it will tell me what network is in use), but the problem is I don't know what to add in the manifest file to start BroadcastReceiver when the network state changes or when it connects to some kind of network

Answer 1

You need

<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 inside manifest tag:

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

To check connectivity, you can use ConnectivityManager as it tells you what type of connection is available.

ConnectivityManager conMngr = (ConnectivityManager)this.getSystemService(this.CONNECTIVITY_SERVICE);
android.net.NetworkInfo wifi = conMngr.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
android.net.NetworkInfo mobile = conMngr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);

Answer 2

This is what I do to get notified when connection has changed. You define a BroadCastReceiver to receive the broadcast.

public class NetworkChangeReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        ConnectivityManager connMgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo wifi = connMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
        NetworkInfo mobile = connMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);

        boolean isConnected = wifi != null && wifi.isConnectedOrConnecting() ||
            mobile != null && mobile.isConnectedOrConnecting();
        if (isConnected) {
            Log.d("Network Available ", "YES");
        } else {
            Log.d("Network Available ", "NO");
        }
    }
}

You also have to define that BroadcastReceiver in your manifest file and filter by ConnectivityChange .

<receiver android:name=".NetworkChangeReceiver" >
        <intent-filter>
            <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
        </intent-filter>
</receiver>

Source here

Answer 3

You should make an BroadcastReceiver that will be triggered when the connectivity status has changed :

Here Same question How to check the Internet Connection periodically in whole application?

Answer 4

To complement @Dantalian's answer. Starting with Android Nougat you should not declare your receiver on your Manifest because it will not receive the CONNECTIVITY_ACTION broadcast. You should instead register your receiver using the Context.registerReceiver(Receiver, Intent) method.

Link to the source here

Answer 5

Declare the intent filter to pass to the broadcastreceiver

IntentFilter filter = new IntentFilter(WifiManager.WIFI_STATE_CHANGED_ACTION);
registerReceiver(mReceiver, filter);

In the broadcast receiver, check for EXTRA_WIFI_STATE;

private BroadcastReceiver mReceiver = new BroadcastReceiver() {
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();

        switch (action)
        {
            case WifiManager.WIFI_STATE_CHANGED_ACTION:
                int extra = intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE,0);
                if(extra==WifiManager.WIFI_STATE_ENABLED)
                {

                }//...else WIFI_STATE_DISABLED, WIFI_STATE_DISABLING, WIFI_STATE_ENABLING
                break;
        }

    }
};