I hadn't looked closely at your SET method but you're being bitten by the same problem. You're copying references, not data by doing it the way you currently are. Try:
mGroups = new ArrayList<Group>(s); Which will create a NEW ArrayList object containing everything that your "s" arraylist contains. Chris On Apr 14, 9:43 am, Duskox <[email protected]> wrote: > Ok I tried now, bumped into antoher error but that is not related to > this problem. > > But I noiced that now that I initialize or better say instantiate this > variable, array exists but is still empty, SET doesn't work. I guess > that was the problem all along, my setGlobalArrayVariable method is > not doing it's job :-/ > > On Apr 14, 3:23 pm, Chris <[email protected]> wrote: > > > > > > > > > This isn't C++. :) In Java, a variable to an object is a > > ReferenceType. It's kind of like a pointer in C++. So think of it this > > way. If you created a pointer variable and passed it around without > > actually making it POINT to something first, what would happen? You're > > passing around a NULL pointer. You need to create an object first > > which you're now doing in onCreate as you've said. Of course you don't > > need to do this if your code is setup such that it ALWAYS calls SET > > before GET. It's fine to do a lazy initialization like that I guess. > > > Chris > > > On Apr 14, 8:57 am, Duskox <[email protected]> wrote: > > > > Thanks that fixed it! > > > > I created override of OnCreate in my application class and declared a > > > new ArrayList. The only thing then puzzles me is why I had to do it?? > > > I thought that it would automatically be filled with the object I > > > created in my init function that is inside of the initial Activity > > > class. I was thinking along the lines that this is like a pointer > > > variable and then I set it with passing a pointer to my object. I > > > guess it doesn't work that way :D > > > > Thanks again!! > > > > On Apr 14, 2:47 pm, Chris <[email protected]> wrote: > > > > > You never instantiate mGroups in your Application class so unless you > > > > SET it before GETing it, it's going to be null. > > > > > Chris > > > > > On Apr 14, 8:31 am, Duskox <[email protected]> wrote: > > > > > > Hi all, > > > > > > so I searched the net and found a nice way to make a global variable > > > > > by creating a class that extends Application class. I did that. But I > > > > > am having problems with it. So this is the situation: > > > > > > public class Group { > > > > > public String mName; > > > > > public int mID; > > > > > public ArrayList<Items> mItems; > > > > > > } > > > > > > public class Item { > > > > > public String mName; > > > > > > } > > > > > > public class MyApplicationApp extends Application { > > > > > private ArrayList<Group> mGroups; > > > > > > public ArrayList<Group> getGlobalArrayVariable() { > > > > > return mGroups; > > > > > } > > > > > > public synchronized void > > > > > setGlobalArrayVariable(ArrayList<Group> s) { > > > > > mGroups = s; > > > > > } > > > > > > } > > > > > > So these are the classes I believe are cruical for this question. Next > > > > > this is that in my Activity classes I set and get this ArrayList > > > > > variable. So I set it in my initial Activity class that is called when > > > > > the application is run. There I fill the array and just to be sure I > > > > > read it with Log functionality after filling the array in the > > > > > MyApplicationApp class and everything is ok. > > > > > > Then I try to read this from another Activity class where I go to > > > > > after a menu choice. In that activity I successfully read the > > > > > application, meaning I get a handle to MyApplicationApp object (I > > > > > guess). This is how I do it: > > > > > > ... > > > > > private MyApplicationApp mMyApp; > > > > > private ArrayList<Group> mGroupsList; > > > > > > protected void onCreate(Bundle savedInstanceState) { > > > > > super.onCreate(savedInstanceState); > > > > > > mMyApp = (MyApplicationApp)this.getApplication(); > > > > > if (mMyApp == null) Log.i(TAG,"mMyApp == null"); > > > > > > mGroupsList = > > > > > (ArrayList<Group>)mMyApp.getGlobalArrayVariable(); > > > > > if (mGroupsList == null) Log.i(TAG,"1. mGroupsList == > > > > > null"); > > > > > > mGroupsList = > > > > > ((MyApplicationApp)this.getApplication()).getGlobalArrayVariable(); > > > > > if (mGroupsList == null) Log.i(TAG,"2. mGroupsList == > > > > > null"); > > > > > ... > > > > > > So mMyApp is not null and that is fine I guess, but mGroupsList is > > > > > null and I presume that is way my app crashes after this last log > > > > > entry. I guess it crashes because my variable is null?? Anyway even if > > > > > the reason for crashing is other then this variable being null I am > > > > > still puzzled why am I not able to get my global variable in this > > > > > way?? > > > > > > The reason for two different ways of getting something into > > > > > mGroupsList variable is because I was trying to see if I am doing it > > > > > incorrectly but it is the same as far as I know... > > > > > > Any ideas or pointers what should I do? > > > > > > Thanks! > > > > > D. -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
