CODEWITHSUNDEEP
javaandroidmultithreading
Cbour
Cbour

Reputation: 59

how to send data from thread to main activity java android

I have a thread that i want to make some calculations and after that send it to the main activity of my program. how i can do that?

the thread is 

class RemindTask extends TimerTask {
    public void run() {
        flag = true;
        System.out.println(" Hello World!");
        for (int e=0; e<2; e++){
            fileToReceive = fileparts.peek();
            System.out.println("fileToReceive "+fileToReceive);
            fileToReceive = fileparts.remove();
        }
        IntegerResult = 4;
        flag=false; 
    }

I want to send the IntegerResult to the main activity. this Timer is called from the activity from here 

Timer timer = new Timer();
                       timer.schedule(new RemindTask(), 0,30000);

and after that i need to take the IntegerResult to the main activity to the main so tha main method is 

int i=0;
//IntegerResult = 4; here i need to take the result of the thread
while (!fileparts.isEmpty()  ) { //&& !fileparts1.isEmpty() && (flag == false) 
    String[] myStringArray = new String[IntegerResult];
    for (int e=0; e<IntegerResult; e++){
        if (fileToReceive != null && !fileparts.isEmpty() ){
            fileToReceive = fileparts.peek();
            myStringArray[e] =  fileToReceive;
            fileToReceive = fileparts.remove();
         } else {
            myStringArray[e] =  " ";
         }
         System.out.println("myStringArray["+e+"] " + myStringArray[e]);
    }

Upvotes: 2

Views: 9753

Answers (3)

Thiago Moura
Thiago Moura

Reputation: 358

There are two ways:

  1. Use this on an ASyncTask, as mentioned before.
  2. Create a handler to receive the response.

something like:

public static int YOUR_INT_MESSAGE = 100;

class RemindTask extends TimerTask {
    public void run() {
        flag = true;
        System.out.println(" Hello World!");
        for (int e=0; e<2; e++){
            fileToReceive = fileparts.peek();
            System.out.println("fileToReceive "+fileToReceive);
            fileToReceive = fileparts.remove();
        }
        IntegerResult = 4;
        flag=false; 
        Message msg = new Message();
        msg.what = YOUR_INT_MESSAGE;
        msg.obj = IntegerResult;
        YourActivity.this.handler.sendMessage(msg);
    }

and on your MainActivity implement the handler

public Handler handler;

handler = new Handler() {
    @Override
    public void handleMessage(android.os.Message msg) {
        if (msg.what == YOUR_INT_MESSAGE) {
            int i=0;
            IntegerResult = msg.obj;
            while (!fileparts.isEmpty()  ) { //&& !fileparts1.isEmpty() && (flag == false) 
                String[] myStringArray = new String[IntegerResult];
                for (int e=0; e<IntegerResult; e++){
                     if (fileToReceive != null && !fileparts.isEmpty() ){
                         fileToReceive = fileparts.peek();
                         myStringArray[e] =  fileToReceive;
                         fileToReceive = fileparts.remove();
                     } else {
                         myStringArray[e] =  " ";
                 }
                 System.out.println("myStringArray["+e+"] " + myStringArray[e]);
             }
        }
    }
}

I cannot test the code above right now, but it's going to be something like that, if you want the Handler approach.

Upvotes: 5

Eugene Loy
Eugene Loy

Reputation: 12446

Seems like what you need is AsyncTask

You can go with Service as Rstar proposed, but it sesms to be a little overkill.

Upvotes: 0

Ronak Mehta
Ronak Mehta

Reputation: 5979

Updated

Use Custom BroadcastReceiver

Write this in ActivityA.java

 Intent intent = new Intent();
 intent.putExtra("message","hi");
 intent.setAction("com.android.activity.SEND_DATA");
 sendBroadcast(intent);

Write this in ServiceA.java/ActivityB.java

private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
   // Extract data included in the Intent
   String message = intent.getStringExtra("message");
   Log.d("receiver", "Got message: " + message);
  }
};

Now register Receiver

LocalBroadcastManager.getInstance(mContext).registerReceiver(mMessageReceiver,
  new IntentFilter("com.android.activity.SEND_DATA"));

Upvotes: 1

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