Friday, December 24, 2010

[android-developers] Re: Basic String Array question :(

Dear King,

"array indexing is zero-based, so you would start your loop from 0 and
go to 9 (where i  < 10)"
Right sir, I'm aware it's for illustration and I forgot to change it.

"You've initialized an array to exactly three elements. Anything after
that"
This part is essential, if I do not know how many element I have then
I cannot declare it predefine but declare array without value to be
filled later.
That is why I have a for loop to extract value from a XML field to
fill into the array. But the array seems to be null unless I have pre-
initialise it with something.
The for loop only fill the data for dummy value I put, if I initialise
3 dummy values the for loop fill exactly 3 values and leave the rest
empty. If i set set 5 dummy values, the 5 get filled correctly.

Java is not my native and I have read a few java books and written
full running android apps. Then, still unable to figure this out...
maybe I need some beer :D

On Dec 25, 11:08 am, TreKing <treking...@gmail.com> wrote:
> On Fri, Dec 24, 2010 at 8:12 PM, Mystique <joven.ch...@gmail.com> wrote:
> > String[] lv_arr;
>
> > for(int i=1; i<11; i++){
> >                lv_arr[i] = "hello";
> >          }
>
> > When I toast the value of lv_arr[i] it is null.
>
> If this is your actual code, you need to initialize the array.
> String[] lv_arr = new String[11];
>
> Second, array indexing is zero-based, so you would start your loop from 0
> and go to 9 (where i  < 10).
>
>
>
> > If I do this:
>
> > String[] lv_arr = {"hello", hello", "hello"} + the for loop, I can get the
> > hello value when I do the toast. but [3]-[10] is still null value.
>
> You've initialized an array to exactly three elements. Anything after that
> (index 3 and above) is non-existent.
>
> These are really basic Java concepts. If you don't understand this, I highly
> recommend you go study Java on it's own and figure this stuff out before
> trying to do an Android project. You're going to run into a lot of headaches
> if you try to learn both at the same time.
>
> --------------------------------------------------------------------------- ----------------------
> TreKing <http://sites.google.com/site/rezmobileapps/treking> - Chicago
> transit tracking app for Android-powered devices

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