Android: passing data back and forth using intent

Question

I am creating a GPS based app for Android and there are 2 activities Main and LocNames. Main shows my map and LocNames is to get source and destination that user wants. I want to start LocNames when user selected it from menu, user enters names in boxes and I want result to be send back to Main. But I am getting exceptions in doing so.

Here is how my Main calls LocNames:

    public boolean onOptionsItemSelected(MenuItem item) 
{
    switch (item.getItemId()) 
    {
        case R.id.showMyLocation:
            showCurrentLocation();
            break;
        case R.id.showRoute:
            Intent getLocationsIntent = new Intent(Main.this, LocNames.class);
            startActivityForResult(getLocationsIntent, 1);
            break;
    }

Here is how I am trying to set results in onClick of LocNames:

public void onClick(View v) 
{
    // TODO Auto-generated method stub
    source = sourceText.getText().toString();
    destination = destinationText.getText().toString();     
    Intent result = new Intent(LocNames.this, Main.class);
    result.putExtra("src", source);
    result.putExtra("dest", destination);
    setResult(RESULT_OK, result);
}

But my application crashed when I try to use result returned by LocNames

protected void onActivityResult(int requestCode, int resultCode, Intent data) 
{
 if(requestCode == 1 && resultCode == RESULT_OK)
    {
        source = data.getStringExtra("src");
        destination = data.getStringExtra("destination");           
    }
}

I have no prior experience in using setResults but documentation says it takes an int and an intent as argument so I am creating intent for that but I get NullPointerException in OnClick of LocNames.

Regards

Answer 1

You do not need an intent for a specific component. You only need an empty intent. So replace

Intent result = new Intent(LocNames.this, Main.class);

with

Intent intent = new Intent();