Android Development Gotchas

Android Gotchas

Here are some Android development gotchas which I have found

ResumeException

I got this because I overrided onResume but forgot to call super.onResume() DUHH

@Override
protected void onResume() {
super.onResume(); //this was missing
}

Strange exception when starting app.

I added a new activity and found my entire app would not start! And I wasn't even using that app! Things to check

1. Be sure that your resource ids are not duplicated. This causes an error when the app starts, even though it might not yet use the resource.
   1. I have started every resource id with the activity name (e.g. id=myactivity_btnOk)
2. Look for other errors in your resource layout files. If you just made a change, back out the change.

Error loading my new activity

1. Oops, the activity was not declared in the manifest
2. Or oops, it was declared but I did not use the correct namespace

I can't get a non-null location manager

1. If you do not have the correct privileges in your manifest, there is no error but no manager comes back.

Some activity launches when I navigate away from a screen.

1. Check your event handlers to see if they are causing it. I am trying to deregister event handlers when my activity pauses.

My app raises an exception but I am having trouble seeing why.

1. Yuch, I dont love the exception reporting. Try running LOGCAT from ABD. You get much more details.

ABD LOGCAT

LOGCAT is clipping my text.

1. Run it from ABD, then the text all wraps

I put data into an intent, but its different when I pull it out!! The reason: makek sure that you know the type of data that you are storing and use the correct get routine to retrieve it. In my case, I was storing a long but using getIntExtra instead of getLongExtra. Duh.

Intent data = new Intent();
      data.putExtra("NumberOfCats", numberOfCats);
//
//
     int numStored = data.getIntExtra("NumberOfCats"); //gets wrong value because numberOfCats is a long and not an int!

I made a custom list adapter with EditText and such but now it doesn't select or scroll.

Yuch, I am going to blog on this. If the view inside the list can accept clicks/touches, then it screws up the OnItemSelected listener. So you are better off to use things likeTextViews. But I got this to work - see upcoming blog entry.