Error receiving broadCast Intent

Question

When trying to test the broadCastReceiver with the ConnectivityManager.CONNECTIVITY_ACTION , the App crashes and logcat says Error receiving broadcast Intent . please let me know what i am missing.

Code :

public class wifi_socket_01 extends Activity {

TextView tv_conn_status;
TextView tv_conn_ssid;
TextView tv_conn_speed;
TextView tv_conn_strengt;
TextView tv_conn_ip;

EditText et_ip;
ToggleButton tobBtn_connect;
EditText et_msg;
Button btn_send;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    SetUpAllViews(R.layout.activity_main);
    displayWiFiStates();

    this.registerReceiver(this.myWiFiReceiver, 
            new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION));
}

private BroadcastReceiver myWiFiReceiver = new BroadcastReceiver() {

    @Override
    public void onReceive(Context context, Intent intent) {
        // TODO Auto-generated method stub
        NetworkInfo networkInfo = intent.getParcelableExtra(ConnectivityManager.EXTRA_EXTRA_INFO);
        if (networkInfo.getType() == ConnectivityManager.TYPE_WIFI) {
            displayWiFiStates();
        }
    }
};

private void SetUpAllViews(int layout) {
    // TODO Auto-generated method stub
    setContentView(layout);

    tv_conn_status = (TextView) findViewById(R.id.tv_conn_status);
    tv_conn_ssid = (TextView) findViewById(R.id.tv_conn_ssid);
    tv_conn_speed = (TextView) findViewById(R.id.tv_conn_speed);
    tv_conn_strengt = (TextView) findViewById(R.id.tv_conn_strength);
    tv_conn_ip = (TextView) findViewById(R.id.tv_conn_ip);
    et_ip = (EditText) findViewById(R.id.et_ip);
    tobBtn_connect = (ToggleButton) findViewById(R.id.togbtn_connect);
    et_msg = (EditText) findViewById(R.id.et_msg);
    btn_send = (Button) findViewById(R.id.btn_send);
}

protected void displayWiFiStates() {
    // TODO Auto-generated method stub
    String service = Context.CONNECTIVITY_SERVICE;
    ConnectivityManager myConnManager = (ConnectivityManager) getSystemService(service);
    NetworkInfo myNetworkInfo = myConnManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
    WifiManager myWifiManager = (WifiManager)getSystemService(Context.WIFI_SERVICE);
    WifiInfo myWiFiInfo = myWifiManager.getConnectionInfo();

    if(myNetworkInfo.isConnected()) {
        tv_conn_ip.setText("IP: "+myWiFiInfo.getIpAddress());
    }else {
        tv_conn_status.setText("Disconnected");
    }
}

}

LogCat :

11-08 10:26:57.645: E/AndroidRuntime(15348): FATAL EXCEPTION: main
11-08 10:26:57.645: E/AndroidRuntime(15348): Process: com.example.wifi_socket_01, PID:   
15348
11-08 10:26:57.645: E/AndroidRuntime(15348): java.lang.RuntimeException: Error 
receiving broadcast Intent { act=android.net.conn.CONNECTIVITY_CHANGE flg=0x4000010   
(has extras) } in com.example.wifi_socket_01.MainActivity$1@4302f638
11-08 10:26:57.645: E/AndroidRuntime(15348):    at 
android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:782)
11-08 10:26:57.645: E/AndroidRuntime(15348):    at a
ndroid.os.Handler.handleCallback(Handler.java:733)
11-08 10:26:57.645: E/AndroidRuntime(15348):    at 
 android.os.Handler.dispatchMessage(Handler.java:95)
11-08 10:26:57.645: E/AndroidRuntime(15348):    at 
android.os.Looper.loop(Looper.java:157)
11-08 10:26:57.645: E/AndroidRuntime(15348):    at 
android.app.ActivityThread.main(ActivityThread.java:5293)
11-08 10:26:57.645: E/AndroidRuntime(15348):    at  
java.lang.reflect.Method.invokeNative(Native Method)
11-08 10:26:57.645: E/AndroidRuntime(15348):    at   
java.lang.reflect.Method.invoke(Method.java:515)
11-08 10:26:57.645: E/AndroidRuntime(15348):    at 
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
11-08 10:26:57.645: E/AndroidRuntime(15348):    at   
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
11-08 10:26:57.645: E/AndroidRuntime(15348):    at    
dalvik.system.NativeStart.main(Native Method)
11-08 10:26:57.645: E/AndroidRuntime(15348): Caused by: java.lang.NullPointerException
11-08 10:26:57.645: E/AndroidRuntime(15348):    at 
com.example.wifi_socket_01.MainActivity$1.onReceive(MainActivity.java:48)
11-08 10:26:57.645: E/AndroidRuntime(15348):    at 
android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:772)

Answer 1

try this instead:

change your

NetworkInfo networkInfo = intent.getParcelableExtra(ConnectivityManager.EXTRA_EXTRA_INFO);

to

ConnectivityManager cm =
        (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = cm.getActiveNetworkInfo();

from the docs: EXTRA_EXTRA_INFO

The lookup key for a string that provides optionally supplied extra information about the network state.

The lookup key for a string that provides optionally supplied extra information about the network state. The information may be passed up from the lower networking layers, and its meaning may be specific to a particular network type. Retrieve it with getStringExtra(String).

Constant Value: "extraInfo"

so we found the explanation of the root of the problem, it never actually returns networkInfo afterall. Its all about the network state.

hope it helps :)

Answer 2

You are probably missing the correct Android permissions in the AndroidManifest:

 <!-- ANDROID PERMISSIONS -->
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

Answer 3

I ran into the same issue, it turned out to be a null pointer inside the onReceive function, I fixed this by altering

    Boolean up = cm.getActiveNetworkInfo().isConnected();

into

    NetworkInfo info = cm.getActiveNetworkInfo();
    boolean up = false;
    if(info != null && info.isConnected()){
        up = true;
    }

I'm also on Android N, this is happening on a service that runs on the UI thread