Are there any recommendations for request codes values in Android?

Question

Now I am using random numbers for request codes. So, every time I add new activity for startActivityForResult I need to check all other such activities to avoid collisions. May be there are any practices for defining values, non-collidable by design? What do you think?

Answer 1

Actually you don't need to check all your Activities and it doesn't matter much if you've the same values in different Activities.

The idea for the request codes is that you, in your Activity X, in onActivityResult() can distinguish between the results of different requests you started with startActivityForResult().

So if you have 3 different startActivityForResult() calls in your activity, you'll need 3 different request codes in order to be able to distinguish between them in onActivityResult() - so you can tell which result belongs to which start. But if you have another Activity Y where you're doing something similar, it doesn't matter when the request codes there are the same like in Activity X.

Answer 2

If you still need to check the result of an activity and like the visually polished structures please check this method.

Declare the internal class inside your activity class:

class RequestCode {     static final int IMPORT = 100;     static final int WRITE_PERMISSION = 101; } 

Use a code when starting activity:

startActivityForResult(intent, RequestCode.IMPORT); 

Check the result:

public void onActivityResult(int requestCode, int resultCode, Intent data) {     super.onActivityResult(requestCode, resultCode, data);     if (requestCode == RequestCode.IMPORT && resultCode == RESULT_OK) {         //...     } }