hello

im new at developing with android and i have a little problem with my app.

first i have an activity with some elements on it and one button

on button click it changes to a new activity with 5 imagebuttons on it.

i selected an image for one of these buttons.

for another button i wanted to select the image on runtime via source code.

Button bt11 = (Button)findViewById(R.id.bt11);
bt11.setBackgroundResource(R.drawable.a);

as result i see nothing - the new image is not on the button

i think i havent seen something important, but i dont check this

thanks for your help

if you dont understand something, please let me know it

Hi,
U should use ImageButton class if u need to place images in buttons. Button class is used to create push button type widgets ( similar to a HTML Form Submit button ) .

Regards
Satish

thanks for your reply

its clear - i have to use the imagebutton. thats right

now i changed it from button to imagebutton in the source now but nothing happens

its like the view will not be updated after changing something.

is there maybe a statement to update the whole view or something?

Hi,
Can u post the code snippet that u say is not working for u ? To update a View , invalidate() has to be called. invalidate() inturn invokes onDraw() on the View. But this method is rarely needed.
should work correctly.

here is the code of my second activity, with the buttons




invalidate?

from witch class is this method?

Hi,
Have u used


in ur GameActivity ? . Other than that, ur code looks good.
invalidate() is available for any Class that extends View such as ImageButton. For ur need, u don't have to use it.

omg - here is a big problem - nothing changes

no i have



but its also without changes

infuriatingly

Hi,
Do u use
Is the onCreate() method of ur new activity (GameActivity ) getting invoked ?
I have tried launching new activities from an existing activity on a UI event such as a button click. It works for me.

ok now i got it

it was this context.startActivity()

i started it false.

thank you man

but now i get an exception at



any hints?

findViewById() will always be null when used before setContentView()

oooooohhhh yes

now it works !!

thanks to all here