Use onactivityresult android

Define constant

public static final int REQUEST_CODE = 1;

Call your custom dialog activity using intent

Intent intent = new Intent(Activity.this,
                    CustomDialogActivity.class);
            startActivityForResult(intent , REQUEST_CODE);

Now use onActivityResult to retrieve the result

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        try {
            super.onActivityResult(requestCode, resultCode, data);

            if (requestCode == REQUEST_CODE  && resultCode  == RESULT_OK) {

                String requiredValue = data.getStringExtra("key");
            }
        } catch (Exception ex) {
            Toast.makeText(Activity.this, ex.toString(),
                    Toast.LENGTH_SHORT).show();
        }

    }

In custom dialog activity use this code to set result

Intent intent = getIntent();
intent.putExtra("key", value);
setResult(RESULT_OK, intent);
finish();

This is my example.

protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == Image_Request_Code && resultCode ==RESULT_OK && data != null && data.getData() != null) {

            FilePathUri = data.getData();

            try {

                // Getting selected image into Bitmap.
                Bitmap bitmap = MediaStore.Images.Media.getBitmap(getContentResolver(), FilePathUri);

                // Setting up bitmap selected image into ImageView.
                SelectImage.setImageBitmap(bitmap);

                // After selecting image change choose button above text.
                ChooseButton.setText("Image Selected");

            }
            catch (IOException e) {

                e.printStackTrace();
            }
        }*strong text*

Start the Activity:

you do need to pass an additional integer argument to the startActivityForResult() method.You may do it by defining a constant or simply put an integer.The integer argument is a "request code" that identifies your request. When you receive the result Intent, the callback provides the same request code so that your app can properly identify the result and determine how to handle it.

static final int ASK_QUESTION_REQUEST = 1;
// Create an Intent to start SecondActivity
Intent askIntent = new Intent(FirstActivity.this, SecondActivity.class);

// Start SecondActivity with the request code
startActivityForResult(askIntent, ASK_QUESTION_REQUEST);

Return The Result:

After completing your work in second activity class simply set the result and call that activity where it comes from and lastly don't forget to write finish() statement.

// Add the required data to be returned to the FirstActivity
            sendIntent.putExtra(Result_DATA, "Your Data");

            // Set the resultCode to Activity.RESULT_OK to
            // indicate a success and attach the Intent
            // which contains our result data
            setResult(RESULT_OK, sendIntent);

            // With finish() we close the SecondActivity to
            // return to FirstActivity
            finish();

Receive The Result:

When you done with the subsequent activity and returns, the system calls your activity's onActivityResult() method. This method includes three arguments:

@The request code you passed to startActivityForResult(). @A result code specified by the second activity. This is either RESULT_OK if the operation was successful or RESULT_CANCELED if the operation failed @An Intent that carries the result data.

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    // check if the request code is same as what is passed  here it is 1
    if (requestCode == ASK_QUESTION_REQUEST) {
        // Make sure the request was successful
        if (resultCode == RESULT_OK) {
            final String result = data.getStringExtra(SecondActivity.Result_DATA);

            // Use the data - in this case display it in a Toast.
            Toast.makeText(this, "Result: " + result, Toast.LENGTH_LONG).show();
        }
    }
}

1.In your FirstActivity class write following code for the move to second activity using Intent.

Intent i = new Intent(this, SecondActivity.class);
startActivityForResult(i, 100);

2.In your secondActivity class write following code for onClick Event For ex: In secondActivity if you want to send back data:

Intent intent= new Intent();
intent.putExtra("result",result);
setResult(RESULT_OK,intent);
finish();

3.Now in your FirstActivity class write following code for the onActivityResult() method.

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) 
{
    if (requestCode == 100 && resultCode == Activity.RESULT_OK){
            String result=data.getStringExtra("result");
            Log.e("Result",result);
    }
}