Question

I’m very new to Android Programming, It would be really great if someone can help me in this.My project contains two JAVA files.

MainActivity.java extends Activity
SMSReceiver.java extends Broadcastreceiver

The SMSreceiver.java has the code which displays any incoming SMS in toast. Can you please tell me how to call a function in MainActivity whenever a particular SMS is received. For eg: when I receive sms called as starttemp it should call a function starttemp.

I have searched a lot and found that intents are a way to do this and we cannot call these methods directly. Please can anyone help me in this? And it would be really great if someone can send me working code.

This would be my MainACtivity.Java

package com.wissen.sms;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.TextView;
import android.widget.EditText;  
import android.widget.Button;
import android.widget.ToggleButton;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Set;
import java.util.UUID;

@SuppressLint({ "NewApi", "NewApi", "NewApi", "NewApi", "NewApi", "NewApi", "NewApi", "NewApi", "NewApi", "NewApi" }) public class MainActivity extends Activity 
{
    TextView myLabel;
    EditText myTextbox;
    ToggleButton switch1;


    BluetoothAdapter mBluetoothAdapter;
    BluetoothSocket mmSocket;
    BluetoothDevice mmDevice;
    OutputStream mmOutputStream;
    InputStream mmInputStream;
    Thread workerThread;
    byte[] readBuffer;
    int readBufferPosition;
    int counter;
    String status;
    volatile boolean stopWorker;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Button openButton = (Button)findViewById(R.id.open);
        Button sendButton = (Button)findViewById(R.id.send);
        Button closeButton = (Button)findViewById(R.id.close);
        myLabel = (TextView)findViewById(R.id.label);
        myTextbox = (EditText)findViewById(R.id.entry);




      //switch1
        switch1 = (ToggleButton) findViewById(R.id.switch1);
        switch1.setOnClickListener(new OnClickListener()
            {
            public void onClick(View v)
            {
                if(switch1.isChecked()){
                    try 
                {
                    String msg = "01ON";
                    msg += "\n\r";
                    mmOutputStream.write(msg.getBytes());
                    myLabel.setText("Data Sent");
                }
                catch (IOException ex) { }

                }else{
                    try 
                {
                    String msg = "01OF";
                    msg += "\n\r";
                    mmOutputStream.write(msg.getBytes());
                    myLabel.setText("Data Sent");

                }
                catch (IOException ex) { }
                }
             }

             });


        //Open Button
        openButton.setOnClickListener(new View.OnClickListener()
        {
            public void onClick(View v)
            {
                try 
                {
                    findBT();
                    openBT();
                }
                catch (IOException ex) { }
            }
        });

        //Send Button
        sendButton.setOnClickListener(new View.OnClickListener()
        {
            public void onClick(View v)
            {
                try 
                {
                    sendData();
                }
                catch (IOException ex) { }
            }
        });

        //Close button
        closeButton.setOnClickListener(new View.OnClickListener()
        {
            public void onClick(View v)
            {
                try 
                {
                    closeBT();
                }
                catch (IOException ex) { }
            }
        });


    }

    void findBT()
    {
        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        if(mBluetoothAdapter == null)
        {
            myLabel.setText("No bluetooth adapter available");
        }

        if(!mBluetoothAdapter.isEnabled())
        {
            Intent enableBluetooth = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableBluetooth, 0);
        }

        Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices();
        if(pairedDevices.size() > 0)
        {
            for(BluetoothDevice device : pairedDevices)
            {
                if(device.getName().equals("HomeAutomation")) 
                {
                    mmDevice = device;
                    break;
                }
            }
        }
        myLabel.setText("Bluetooth Device Found");
    }

    void openBT() throws IOException
    {
        UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb"); //Standard SerialPortService ID
        mmSocket = mmDevice.createRfcommSocketToServiceRecord(uuid);        
        mmSocket.connect();
        mmOutputStream = mmSocket.getOutputStream();
        mmInputStream = mmSocket.getInputStream();

        beginListenForData();

        myLabel.setText("Bluetooth Opened");
    }

    void beginListenForData()
    {   
        final Handler handler = new Handler(); 
        final byte delimiter = 10; //This is the ASCII code for a newline character

        stopWorker = false;
        readBufferPosition = 0;
        readBuffer = new byte[1024];
        workerThread = new Thread(new Runnable()
        {
            public void run()
            {               
               while(!Thread.currentThread().isInterrupted() && !stopWorker)
               {
                    try 
                    {


                        int bytesAvailable = mmInputStream.available();                        
                        if(bytesAvailable > 0)
                        {
                            byte[] packetBytes = new byte[bytesAvailable];
                            mmInputStream.read(packetBytes);
                            for(int i=0;i<bytesAvailable;i++)
                            {
                                byte b = packetBytes[i];
                                if(b == delimiter)
                                {
                                    byte[] encodedBytes = new byte[readBufferPosition];
                                    System.arraycopy(readBuffer, 0, encodedBytes, 0, encodedBytes.length);
                                    final String data = new String(encodedBytes, "US-ASCII");
                                    readBufferPosition = 0;

                                    handler.post(new Runnable()
                                    {
                                        public void run()
                                        {   
                                            status=data;
                                            myLabel.setText(data);
                                        }
                                    });
                                }
                                else
                                {
                                    readBuffer[readBufferPosition++] = b;
                                }
                            }
                        }
                    } 
                    catch (IOException ex) 
                    {
                        stopWorker = true;
                    }
               }
            }
        });

        workerThread.start();
    }


    void sendData() throws IOException
    {
        String msg = myTextbox.getText().toString();
        msg += "\n\r";
        mmOutputStream.write(msg.getBytes());
        myLabel.setText("Data Sent");
    }

    void closeBT() throws IOException
    {
        stopWorker = true;
        mmOutputStream.close();
        mmInputStream.close();
        mmSocket.close();
        myLabel.setText("Bluetooth Closed");
    }
}

This would be My SMSReceiver.Java

package com.wissen.sms.receiver;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.telephony.gsm.SmsMessage;
import android.widget.Toast;


public class SMSReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        Bundle bundle = intent.getExtras();

        Object messages[] = (Object[]) bundle.get("pdus");
        SmsMessage smsMessage[] = new SmsMessage[messages.length];
        for (int n = 0; n < messages.length; n++) {
            smsMessage[n] = SmsMessage.createFromPdu((byte[]) messages[n]);
        }

        Toast toast = Toast.makeText(context, "Received SMS: " + smsMessage[0].getMessageBody(), Toast.LENGTH_LONG);
        toast.show();
    }
}

Now i want to call a method of MainActivity.java whenever a new message is received

void somemethod()
{

try 
{
            String msg = "01ON";
                msg += "\n\r";
                mmOutputStream.write(msg.getBytes());
                myLabel.setText("Data Sent");
}
catch (IOException ex) { }



}
}

Answer 1

One best way for use MainActivity method from Broadcast receiver class is

Define your method as a static and than you can use that method using below code

Activityname.methodname()

I tried this and its worked fine for me.

for example

public class SMSBroadcastReceiver extends BroadcastReceiver {

    private static final String SMS_RECEIVED = "android.provider.Telephony.SMS_RECEIVED";
    private static final String TAG = "SMSBroadcastReceiver";

    @Override
    public void onReceive(Context context, Intent intent) {
         Log.i(TAG, "Intent recieved: " + intent.getAction());

            if (intent.getAction() == SMS_RECEIVED) {
                Bundle bundle = intent.getExtras();
                if (bundle != null) {
                    Object[] pdus = (Object[])bundle.get("pdus");

                     abc.methodtocall();

                }
            }
       }
}

and your Activity code like this

public class abc extends Activity{


@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
}

public static void methodtocall(){

    //Your code here...

}

}