Android Question Connect to wifi without internet

[Michael Wenning]

I have a project with ESP8266 as a Access Point with Wifi connection. It has no internet connectivity.
Most mobile phones work good. I have problems with never Sony mobiles (Android 8.1 and 9.0).
They connect to the ESP8226, detect there is no internet connectivity and disconnect. I have found Erels solution for this in
https://www.b4x.com/android/forum/threads/mqtt-chat-network-error.90892/

It's based on:
... cm.InitializeStatic("android.net.ConnectivityManager").RunMethod("setProcessDefaultNetwork", Array(Network))

from: https://developer.android.com/reference/android/net/ConnectivityManager
i found this for never Android version:

static boolean setProcessDefaultNetwork(Network Network)
This method was deprecated in API level 23.
This function can throw IllegalStateException.
Use bindProcessToNetwork(Network) instead. bindProcessToNetwork Is a direct replacement.

1. Can someone please help me to implement this (always got error messages)?

2. Is there a better solution? What can i do?

Thank's a lot for your help and best regards from germany
Michael

 

[Computersmith64]

You can try any of the functions in this class:

Sub Class_Globals
   
End Sub
'Initializes the object. You can add parameters to this method if needed.
Public Sub Initialize
   
End Sub
Public Sub isWifiConnected() As Boolean
    Dim jo As JavaObject = Me
    Dim r As Reflector
    'Return jo.RunMethod("isNetworkConnected", Array(r.GetContext))
    Return jo.RunMethod("isConnected", Array(r.GetContext))
End Sub
#if JAVA
import android.content.Context;
import android.net.ConnectivityManager;
import android.os.Build;
import android.net.Network;
import android.net.NetworkInfo;
import android.net.NetworkCapabilities;
//import anywheresoftware.b4a.BA;
//Pretty much a straight rip from https://stackoverflow.com/a/53078141
public boolean isNetworkConnected(Context context) {
    final ConnectivityManager cm = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
    if (cm != null) {
        if (Build.VERSION.SDK_INT < 23) {
           //BA.Log("Build SDK < 23");
            NetworkInfo ni = cm.getActiveNetworkInfo();
            if (ni != null) {
                return (ni.isConnected() && (ni.getType() == ConnectivityManager.TYPE_WIFI));
            }
        } else {
           //BA.Log("Build SDK >= 23");
            Network n = cm.getActiveNetwork();
            if (n != null) {
                final NetworkCapabilities nc = cm.getNetworkCapabilities(n);
                return (nc.hasTransport(NetworkCapabilities.TRANSPORT_WIFI));
            }
        }
    }
    return false;
}
public boolean getConnectivityStatus(Context context) {
    final ConnectivityManager connManager = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
    //connManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo info = connManager.getActiveNetworkInfo();
    if (info != null)
        return info.isConnected(); // WIFI connected
    else
        return false; // no info object implies no connectivity
}
 public static boolean isConnected(Context context){
        ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
            Network[] activeNetworks = cm.getAllNetworks();
            for (Network n: activeNetworks) {
                NetworkInfo nInfo = cm.getNetworkInfo(n);
                if(nInfo.isConnected())
                    return true;
            }
        } else {
            NetworkInfo[] info = cm.getAllNetworkInfo();
            if (info != null)
                for (NetworkInfo anInfo : info)
                    if (anInfo.getState() == NetworkInfo.State.CONNECTED) {
                        return true;
                    }
        }
        return false;
    }
#End If

However assuming you are using the MLWiFi (SimpleWifi) library, you will still have a problem with Android 9 devices in that you will never get the WiFi to return a connected state if there is no internet connection - per this thread -> Simple Wifi (MLWifi) not working correctly with Android 9

- Colin.

 

[Michael Wenning]

Thank's for reply Colin.

The phone definitely connects to the ESP8266 wifi. It detects that there is no internet connectivity
and cuts connection. My app tries again and again...
I have found Erels solution for Android < 23.
It forces the phone after the wifi connection
to stay in the wifi, no matter if the internet connection exists or not.

Sub PreferWifiRouting As ResumableSub
Dim p As Phone
If p.SdkVersion >= 21 Then
Dim ctxt As JavaObject
ctxt.InitializeContext
Dim builder As JavaObject
builder.InitializeNewInstance("android.net.NetworkRequest.Builder", Null)
Dim manager As JavaObject = ctxt.RunMethod("getSystemService", Array("connectivity"))
builder.RunMethod("addTransportType", Array(1)) 'NetworkCapabilities.TRANSPORT_WIFI
Dim event As JavaObject
event.InitializeNewInstance(Application.PackageName & ".main$NetworkCallback", Null)
manager.RunMethod("requestNetwork", Array(builder.RunMethod("build", Null), event))
Wait For network_available (Network As Object)
Log("Network found.")
Dim cm As JavaObject
Return cm.InitializeStatic("android.net.ConnectivityManager").RunMethod("setProcessDefaultNetwork", Array(Network))
End If
Return False
End Sub

#if Java
public static class NetworkCallback extends android.net.ConnectivityManager.NetworkCallback {
public void onAvailable(android.net.Network network) {
processBA.raiseEventFromUI(null, "network_available", network);
}
}
#End If

The new method for Android > 23 is bindProcessToNetwork(Network).

But i don't know to implement. Please help.

Best regards
Michael

 

[DonManfred]

Please use [CODE]code here...[/CODE] tags when posting code.

 

[Computersmith64]

Sorry - I misread your post. Maybe if you post the code that you've tried & the errors you're getting it might help someone come up with an answer.

- Colin.

 

[Michael Wenning]

Good idea!

Here is the code:

Private Sub PreferWifiRouting  As ResumableSub
    'Dim p As Phone
    'If p.SdkVersion >= 22 Then
    If Starter.wifi.APIversion >= 22 Then
        Dim ctxt As JavaObject
        ' MW 29.03.2019
        Log("PreferWifiRouting Start")
        ctxt.InitializeContext
        Dim builder As JavaObject
        builder.InitializeNewInstance("android.net.NetworkRequest.Builder", Null)
        Dim manager As JavaObject = ctxt.RunMethod("getSystemService", Array("connectivity"))
        builder.RunMethod("addTransportType", Array(1)) 'NetworkCapabilities.TRANSPORT_WIFI
        Dim event As JavaObject
        
        event.InitializeNewInstance(Application.PackageName & ".wificonnect$NetworkCallback", Null)
        
        manager.RunMethod("requestNetwork", Array(builder.RunMethod("build", Null), event))
        Wait For network_available (Network As Object)
        ' MW 29.03.2019
        Log("PreferWifiRouting Network found.")
        
        Dim cm As JavaObject
        
        ' Up to API 22
        
        '' Return cm.InitializeStatic("android.net.ConnectivityManager").RunMethod("setProcessDefaultNetwork", Array(Network))
        
        ' static boolean    setProcessDefaultNetwork(Network Network)
        ' This method was deprecated in API level 23.
        ' This function can throw IllegalStateException.
        ' Use bindProcessToNetwork(Network) instead. bindProcessToNetwork Is a direct replacement.
    
        Return  cm.InitializeStatic("android.net.ConnectivityManager").RunMethod("bindProcessToNetwork", Array(Network))
    
    End If
    Return False
End Sub


#if Java

public static class NetworkCallback extends android.net.ConnectivityManager.NetworkCallback {
    public void onAvailable(android.net.Network network) {
         processBA.raiseEventFromUI(null, "network_available", network);
  }
}

#End If

Here is the error log:

...
Wartezeit [mSek] für Disconnect Versuche: 10
StartConnectToAP: MyBike14313210 ist ein auf dem Handy gespeicherter Access Point!
PreferWifiRouting Start
*** Service (receiver) Create ***
BroadcastReceiver has been initialized.
** Service (receiver) Start **
TimerCheckTimeOutForConnection_Tick!Zeit: 03/30/2019 12:46:23
TimerCheckTimeOutForConnection_Tick!Zeit: 03/30/2019 12:46:24
TimerCheckTimeOutForConnection_Tick!Zeit: 03/30/2019 12:46:25
TimerCheckTimeOutForConnection_Tick!Zeit: 03/30/2019 12:46:26
PreferWifiRouting Network found.
Error occurred on line: 372 (WifiConnect)
java.lang.IllegalArgumentException: Expected receiver of type android.net.ConnectivityManager, but got java.lang.Class<android.net.ConnectivityManager>
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4j.object.JavaObject.RunMethod(JavaObject.java:131)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:732)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:348)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:144)
at anywheresoftware.b4a.BA.raiseEvent(BA.java:176)
at anywheresoftware.b4a.shell.DebugResumableSub$RemoteResumableSub.resume(DebugResumableSub.java:22)
at anywheresoftware.b4a.BA.checkAndRunWaitForEvent(BA.java:250)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:137)
at anywheresoftware.b4a.BA$1.run(BA.java:335)
at android.os.Handler.handleCallback(Handler.java:789)
at android.os.Handler.dispatchMessage(Handler.java:98)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6944)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:327)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1374)


line 372 is: Return cm.InitializeStatic("android.net.ConnectivityManager").RunMethod("bindProcessToNetwork", Array(Network))

Is someone able to help me?

Thank's a lot and regards
Michael

 

[Erel]

The fact that this method is deprecated doesn't mean that you can't use it. That's especially true if you want to support android 5+ devices.

 

[Michael Wenning]

The code with "setProcessDefaultNetwork" runs well whithout errors but it doesn't bring any improvement.
The Sony mobiles connect to the ESP8226, detect there is no internet connectivity and disconnect.
So i want to try out the newer possibility with "bindProcessToNetwork".
The problem is that my Java knowledge is not sufficient for the implementation.

Is someone able to help me?

Thank's a lot and regards
Michael

 

[Michael Wenning]

Hello,
i helped myself and here is the code sample for interested:

'  Service Modul

Sub Process_Globals
  Private nativeMe As JavaObject
End Sub

Sub Service_Create
  nativeMe.InitializeContext
End Sub


' MW 07.04.2019
Public Sub PreferWifiRoutingJava(SollSsid As String) As Int
   
    Dim intErfolg As Int = nativeMe.RunMethod("BindProcessToNetwork", Array (SollSsid))
   
    'Sleep(0)
#If DEBUG      
    Log ("PreferWifiRoutingJava Sub Ergebnis: " & intErfolg)
#End if  
   
    Return intErfolg
   
End Sub

#If Java


 import android.os.Build;
 import android.net.ConnectivityManager;
 import android.net.Network;
 import android.net.NetworkCapabilities;
 import android.net.NetworkInfo;
 import android.net.wifi.SupplicantState;
 import android.net.wifi.WifiInfo;
 import android.net.wifi.WifiManager;
 import android.net.NetworkRequest;
 import android.os.SystemClock;
 import android.net.wifi.WifiConfiguration;
 import java.util.List;
 import android.content.Context;
 import android.content.Intent;
 import android.content.BroadcastReceiver;
 import android.content.IntentFilter;
 import anywheresoftware.b4a.BA;


public String CheckAktuelleSsid () {
        String AktSsid;
        AktSsid ="";
        WifiManager wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);
        WifiInfo wifiInfo;
        wifiInfo = wifiManager.getConnectionInfo();
        if (wifiInfo.getSupplicantState() == SupplicantState.COMPLETED) {
            AktSsid = wifiInfo.getSSID();
            // Ausgabe Logc
           // Log.i(TAG, "Check SSID: " + AktSsid);
        }
        return AktSsid;
    }

   
public int BindProcessToNetwork (final String networkSSID ) {
       
        //String AktuelleSsid;
        intZustand = -99;
       
        // AktuelleSsid ="";
       
        // „Lollipop“    5.0[81]    21        
        if (android.os.Build.VERSION.SDK_INT>=android.os.Build.VERSION_CODES.LOLLIPOP){
         
           final ConnectivityManager manager =(ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
           // ConnectivityManager manager =(ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkRequest.Builder builder;
            builder = new NetworkRequest.Builder();
            //set the transport Type Do WIFI
            builder.addTransportType(NetworkCapabilities.TRANSPORT_WIFI);
            manager.requestNetwork(builder.build(), new ConnectivityManager.NetworkCallback() {
              @Override
              public void onAvailable(Network network) {
                       int intZustandCb = 0;
                    boolean connected = false;
                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                        connected = manager.bindProcessToNetwork(null);
                         
                        final String AktuelleSsid = CheckAktuelleSsid();
                        // BA.Log("bindProcessToNetwork AktuelleSsid: " + AktuelleSsid);
                        // BA.Log("bindProcessToNetwork networkSSID: " + networkSSID);
                       
                           if (AktuelleSsid.contains(networkSSID)) {
                       
                            manager.bindProcessToNetwork(network);
                            if (connected) {
                                // Log.i(TAG, "bindProcessToNetwork OK: " + network.toString());
                                BA.Log("bindProcessToNetwork OK: " + network.toString());
                                intZustandCb = 1;
                            }
                            else {
                                //Log.i(TAG, "bindProcessToNetwork NOK: " + network.toString());
                                BA.Log("bindProcessToNetwork NOK: " + network.toString());
                                intZustandCb = 2;
                            }
                        }
                    } else {
                        //This method was deprecated in API level 23
                        connected = ConnectivityManager.setProcessDefaultNetwork(network);
                        if (connected) {
                            //Log.i(TAG, "setProcessDefaultNetwork OK: " + network.toString());
                            BA.Log("setProcessDefaultNetwork OK: " + network.toString());
                            intZustandCb = 3;
                        }
                        else {
                            //Log.i(TAG, "setProcessDefaultNetwork NOK: " + network.toString());
                            BA.Log("setProcessDefaultNetwork NOK: " + network.toString());
                            intZustandCb = 4;
                        }
                    }
                    try {
                        //Do a callback Or something Else To alert your code that it's ok to send the message through socket now
                    } catch (Exception e) {
                        e.printStackTrace();
                        intZustandCb = -11;
                    }
                    manager.unregisterNetworkCallback(this);
                   // Log.i(TAG, "unregisterNetworkCallback");
                   //BA.Log("Ende mit unregisterNetworkCallback");
                   intZustandCb += 10;
                   //BA.Log("Callback Zustand Callback: " + String.valueOf(intZustandCb));
                   intZustand = intZustandCb;
                }
            });
           
        }
       
        // BA.Log("Zustand Aussen vorher: " + String.valueOf(intZustand));
       
        int i = 0;
               
        do {
            SystemClock.sleep(1);
            i++;
            //BA.Log("Zaehler i: " + String.valueOf(i));
            if (i > 200){
              intZustand = -1;
              break;
            }
        } while (intZustand < - 1);
       
        BA.Log("Zaehler i: " + String.valueOf(i));
        //BA.Log("Zustand Aussen Nachher: " + String.valueOf(intZustand));
       
        // MkGestartet = false;
       
        return intZustand;
               
    } // Ende von: Public void BindProcessToNetwork...
   
 
#End If

Best regards from Germany
Michael

 

[Nitin Joshi]

Hi Michael,
Is your problem resolved? I am also facing same problem and yet not found any solution.