How to send data to Flutter from native (Android)

Question

I need to pass data from the below class to my flutter app where the data is only available when an incoming call event happens. i need to pass this data(mobileNumber) to flutter (if possible i need to pass data even the flutter app is terminated)

BroadcastReciever.java

package com.ashbu.flutterappbackground;
...

public class MyBroadcastReceiver extends BroadcastReceiver {
    String phoneNumber;

        @Override
        public void onReceive(final Context context, Intent intent) {
            TelephonyManager telephony = (TelephonyManager)context.getSystemService(Service.TELEPHONY_SERVICE);
            telephony.listen(new PhoneStateListener(){
                @Override
                public void onCallStateChanged(int state, String incomingNumber) {
                    super.onCallStateChanged(state, incomingNumber);
                    phoneNumber = incomingNumber;
                    Toast.makeText(context, "TeleDuce Customer "+ incomingNumber,
                Toast.LENGTH_LONG).show();
                }
            },PhoneStateListener.LISTEN_CALL_STATE);
        }


   public  String getData() {
    String number = null;
    if (phoneNumber != null) {
        number = phoneNumber;
    }else {
        number = "noData";
    }
    return number;
    }

} from the above code, i need to pass incomingNumber to flutter. if possible - Share the data even the app is closed.

MainActivity.java

public class MainActivity extends FlutterActivity {
private static final String CHANNEL = "samples.flutter.dev/getNumber";

AlarmManager alarmManager;
PendingIntent pendingIntent;

@Override
public void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) {
    super.configureFlutterEngine(flutterEngine);
    alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
    Intent alarmIntent = new Intent(this, MyService.class);
    pendingIntent = PendingIntent.getBroadcast(this, 0, alarmIntent, 0);

    new MethodChannel(flutterEngine.getDartExecutor().getBinaryMessenger(), CHANNEL)
            .setMethodCallHandler(
                    (call, result) -> {

                        // Note: this method is invoked on the main thread.
                        if (call.method.equals("getMobileNumber")) {
                            startAlarm();
                            MyBroadcastReceiver dataGEt = new MyBroadcastReceiver();
                            System.out.println(dataGEt.getData());
                            result.success(dataGEt.getData());
                        } else {
                            cancelAlarm();
                        }
                    }
            );
}

private void startAlarm() {

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        alarmManager.setAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, 0, pendingIntent);
    } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
        alarmManager.setExact(AlarmManager.RTC_WAKEUP, 0, pendingIntent);
    } else {
        alarmManager.set(AlarmManager.RTC_WAKEUP, 0, pendingIntent);
    }
}

private void cancelAlarm() {
    alarmManager.cancel(pendingIntent);
    Toast.makeText(getApplicationContext(), "Alarm Cancelled", Toast.LENGTH_LONG).show();
}
}

Currently the above code will work even the app is terminated. But i don't know if the flutter will accept the data after the app is terminated

user_9512756 · Answer

You should be implement methodHandler in Flutterside and you should be make static object of methodchannel

For Example

class MethodChannelHelper {
  static const MethodChannel channel = const MethodChannel('method_channal_name');
}
class MethodChannelCall{
        static initMethodChannel({Function onCallBack}) async {
            MethodChannelHelper.channel.setMethodCallHandler((MethodCall call) async {
              switch (call.method) {
                case 'callback_from_native':
                  print("This method will be called when native fire")
              }
            });
     await MethodChannelHelper.channel.invokeMethod('call_native');
          }
}

In main.dart

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await MethodChannelCall.initMethodChannel(onCallBack: (payload) {

  });
  runApp(MyApp());
}

Now In Android side

 override fun onMethodCall(@NonNull call: MethodCall, @NonNull result: Result) {
 when (call.method) {
            "call_native" -> {
            methodChannel?.invokeMethod("callback_from_native","")

}
}

user_17552057 · Answer

I passed the list as the argument from main.dart to MainActivity.kt class

in main.dart

var  items =['hello', 'hii', 'flowers', 'roses','loutes']; 
 Future _getDeviceInfo() async {
    String result;
    try {
      platform.invokeMethod('getDeviceInfo' , items).then((items) {
        result = items.toString();
        setState(() {
          deviceInfo = result;
        });
      });
    } on PlatformException catch (e) {
      print("_getDeviceInfo==>${e.message}");
    }
  }

In MainActivity.kt class

package com.example.flutter_to_native


import android.content.Intent
import android.os.Bundle
import android.os.PersistableBundle
import android.util.Log

import androidx.annotation.NonNull
import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugin.common.MethodChannel

class MainActivity : FlutterActivity() {
    private val CHANNEL = "com.example.flutter/device_info" // Unique Channel


    override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
        super.configureFlutterEngine(flutterEngine)

        MethodChannel(flutterEngine.dartExecutor.binaryMessenger, CHANNEL).setMethodCallHandler {
            // Note: this method is invoked on the main thread.
                call, result ->
            if (call.method == "getDeviceInfo") {
                val data = call.arguments
                Log.d("data1", "$data")
                val intent = Intent(this, DemoActivity::class.java)
                intent.putExtra("data",data.toString())
                startActivity(intent)

              else {
                result.notImplemented()
            }

        }
    }


    
}

How to send data to Flutter from native (Android)

2 Answers