UIButton change dimensions at run time - ios

Question

I have a xib file of UIView which has 2 buttons in it. Like this :
Button1 will be either hidden on shown. When it is hidden I want other button to take away whole space.
I also want the view to occupy all available space (orientation change also to be managed). In IB for view, I have selected Size as Freeform, Orientation as Portrait.
For that I added Constraints to both buttons setting 0 to top, bottom and left/right. But with this, when orientation is changed their is gap between both the buttons which I don't want.
I tried many ways but am not able to handle the above two matters. Both are also inter-related. If Button1 is hidden, then should add left constraint to other button also. Right now, I have removed all constraints, so in landscape it doesn't utilize full space.
Can you let me know how do I handle this inter-related issues.
UPDATE
Added the following method to the view (UIView) class. Adding it like this is new for me, with reference have written code to add for top, bottom and left/right setting 0 on both buttons. Left with main role - button1 is hidden then what to add and shown then what.
-(void) addCustomConstriants:(BOOL) hideFirstBtn {
// http://technet.weblineindia.com/mobile/ui-design-of-ios-apps-with-autolayout-using-constraints-programmatically/2/
//NSDictionary *viewsDict = NSDictionaryOfVariableBindings(self.button1, self.button2);
//NSArray *constriaints =
if (hideFirstBtn) {
// ONLY 2ND BUTTON - NO 1ST BUTTON
} else {
// SHOW BOTH BUTTONS
// BUTTON 1
// ADD TOP CONSTRAINT - 0
[self addConstraint:[NSLayoutConstraint constraintWithItem:self.button1 attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeTop multiplier:1.0 constant:0.0] ];
// ADD BOTTOM - 0
[self addConstraint: [NSLayoutConstraint constraintWithItem:self.button1 attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeBottom multiplier:1.0 constant:0.0 ] ];
// LEFT
[self addConstraint: [NSLayoutConstraint constraintWithItem:self.button1 attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeLeft multiplier:1.0 constant:0.0 ] ];
// BUTTON 2
// ADD TOP CONSTRAINT - 0
[self addConstraint:[NSLayoutConstraint constraintWithItem:self.button2 attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeTop multiplier:1.0 constant:0.0] ];
// ADD BOTTOM - 0
[self addConstraint: [NSLayoutConstraint constraintWithItem:self.button2 attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeBottom multiplier:1.0 constant:0.0 ] ];
// ADD RIGHT - 0
[self addConstraint: [NSLayoutConstraint constraintWithItem:self.button2 attribute:NSLayoutAttributeRight relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeRight multiplier:1.0 constant:0.0 ] ];
// Width constraint, half of parent view width
[self addConstraint:[NSLayoutConstraint constraintWithItem:self.button1
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:self
attribute:NSLayoutAttributeWidth
multiplier:0.5
constant:0]];
// Width constraint, half of parent view width
[self addConstraint:[NSLayoutConstraint constraintWithItem:self.button2
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:self
attribute:NSLayoutAttributeWidth
multiplier:0.5
constant:0]];
// AFTER ADDING WIDTH ALSO FOR BOTH BUTTONS, WILL HAVE TO ADD X SOME HOW ??? PUZZLE ???
}
}
I believe I will also have to set Width for both the buttons. That should be of equal width. If only button2, then that width also will have to set here only right. How to add constraints for them ?
This is how I call this view from other screen :-
vov1 = [visitorOptView objectAtIndex:0];
// note the origin of the frame is (0, 0) since you are adding it to the cell instead of the table view
vov1.frame = CGRectMake(0, 0, selectedCell.frame.size.width, selectedCell.frame.size.height);
btnWidth = selectedCell.frame.size.width;
[vov1.button2 addTarget:self action:#selector(showVisitorDetailsView) forControlEvents:UIControlEventTouchUpInside];
// show/Enable "Start Chat" btn, else Disable it
if (tableView.tag == 0 || tableView.tag ==1) {
// START
[vov1.button1 setTitle:#"Accept" forState:UIControlStateNormal];
[vov1.button1 addTarget:self action:#selector(acceptBtnClicked) forControlEvents:UIControlEventTouchUpInside];
} else if (tableView.tag == 3) {
// CLOSED LIST - HIDE ALL BTNS
[vov1.button1 setHidden:YES];
}
///// HERE addCustomConstraints SHOULD BE CALLED I THINK
// add overlay view to this row
[selectedCell.contentView addSubview:vov1];
Can you help me with the above.

Answer 1

In that case you should add the constraints by code. So when the two buttons are shown. the first button trailing constraint should be bonded to the leading to the second button constraint. If the "View Details" button is the only one shown then hide the first one and the leading constraint to that button will be bonded with the leading of the self.view .
Create a method called addCustomConstraints and call it in viewDidLoad.