Dynamic Button Layout without hard coding positions - iphone

Question

I would like to implement a view (it will actually be going into the footer of a UITableView) that implements 1-3 buttons. I would like the layout of these buttons (and the size of the buttons themselves) to change depending on which ones are showing. An example of almost the exact behavior I would want is at the bottom of the Info screen in the Contacts application when you are looking at a specific contact ("Add to Favorites" disappears when it is clicked, and the other buttons expand to take up the available space in a nice animation).
As I'm running through the different layout scenarios, I'm hard coding all these values and I just think... "this is NOT the way I'm supposed to be doing this."
It even APPEARS that Interface Builder has some features that may do this for me in the ruler tab, but I'll be darned if I can figure out how they work (if they work) on the phone.
Does anyone have any suggestions, or a tutorial online that I could look at to point me in the right direction?
Thanks much.

Answer 1

You could take a look at
Stanford cs193p classes
I think there is a demo in one of the lessons/example where they programaticaly set the autoresize of the buttons and some other where they animate the view.
you can also make the view set dynamically the width of each of its subview to (ownWidth/numberofSubView),the same for the positon of each elements.
[edit] like that ? it's not "dynamic" yet, but you've got the idea
you can increase/decrease numberOfbuttons when "adding/removing" a button then reset the new frame of all the subviews
- (void)loadView
{
UIView *view = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
view.backgroundColor = [UIColor lightGrayColor];
view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
int numberOfbuttons = 2;
CGFloat buttonsLegth = (-20+view.bounds.size.width)/numberOfbuttons-20;
for(int i=0;i<numberOfbuttons;i++){
CGRect buttonFrame = CGRectMake(0, 0, buttonsLegth, 37);
buttonFrame.origin.x = (buttonFrame.size.width+20)*i + 20.0;
buttonFrame.origin.y = 20.0;
UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect]; // Autoreleased
button.frame = buttonFrame;
[button setTitle:#"Done" forState:UIControlStateNormal];
[view addSubview:button];
}
self.view = view;
[view release];
}

Answer 2

hi remove all buttons in view and add again using this method...
you have to pass number of buttons and a UIView in which you want to add these buttons
-(void)addButtons:(int)numberOfButtons ToView:(UIView *)containerView;
{
CGRect containerRect = containerView.frame;
CGFloat padding = 5.0;
CGFloat width = (containerRect.size.width - (padding*numberOfButtons+1))/numberOfButtons;
for (int i = 1; i<=numberOfButtons; i++)
{
UIButton * btn = [[[UIButton alloc] initWithFrame:CGRectMake(i*padding+width, 0, width, containerRect.size.height)]autorelease];
//set Button Properties like Target,backColor,Title,,,,etc MUST SET TAG TO ACCESS THEM IN CLICK METHOD IF YOU ARE USING SAME SELECTOR FOR ALL BUTTONS.
[containerView addSubview:btn];
}
}
Try this and have fun......