In Android: How do I get variables/data from one screen to another?...

Question

In android: I'm trying to take data from one activity/screen to another.

Let's say I'm adding two numbers. I layout my first screen (xml) with 2 EditText views, a couple labels, and an 'OK' button. Now, I want to add the numbers that I've input into the EditText views. Let's say I input 2 and 2 (2 + 2 = 4).

Now, when I hit the 'OK' button, I want a new screen/activity to appear and simply show me the answer (4). Do I use global vars to do this? Any help would be appreciated.

Answer 1

Take a look at the Some Intent examples section (from Common Tasks and How to Do Them in Android):

basically, you use myIntent.putExtra (...) to send data (can be String, Int, Boolean etc) to the other receiving end (the other activity)...

then, result will be passed back into the calling Activity's onActivityResult() method:

protected void onActivityResult(int requestCode, int resultCode, Intent data){
    // See which child activity is calling us back.
    switch (resultCode) {
        case CHOOSE_FIGHTER:
            // This is the standard resultCode that is sent back if the
            // activity crashed or didn't doesn't supply an explicit result.
            if (resultCode == RESULT_CANCELED){
                myMessageboxFunction("Fight cancelled");
            } 
            else {
                myFightFunction(data);
            }
        default:
            break;
    }

H.

Answer 2

I suppose that You're starting "next screen" using Intent (it's the way it should be done).

In Intent you can pass extras (putExtra) and in onCreate in "next activity" you can getIntent().getXExtra() (substitute X with field type)

Answer 3

First Activity

Intent myIntent = new Intent();
myIntent.putExtra("key", "value");
startActivity(myIntent); 

New Activity

Intent myIntent = getIntent(); // this is just for example purpose
myIntent.getExtra("key");

Check out the different types you can use on the Android Dev Site