Question

i will like to know how to expend the width of an UIButton to the left only, pretty much like app store button that will expend towards the left. however i have multiple button to expend.

EDIT this is the working code:

//viewdidload
buttonCaption = [UIButton buttonWithType:UIButtonTypeCustom];
//default placement
buttonCaption.frame = CGRectMake(245, 385, 70, 30); //default width size
[self nextAnimation:buttonCaption.frame.size.width]; 

---

pass default value to animation

-(void)nextAnimation:(float)previousWidth {

//button setting
buttonCaption.titleLabel.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin ;
//buttonCaption.titleLabel.font =[UIFont systemFontOfSize:20];
[[buttonCaption layer] setCornerRadius:5.0f];
[[buttonCaption layer] setMasksToBounds:YES];
[[buttonCaption layer] setBackgroundColor:[[UIColor colorWithRed:0 green:0 blue:0 alpha:0.7] CGColor]];   
[buttonCaption.titleLabel setFrame:CGRectMake(0,0, 25, 25)];   
CGSize stringsize = [tempCaption sizeWithFont:[UIFont systemFontOfSize:20]];  
CGFloat diff = stringsize.width - previousWidth;
NSLog(@"diff %f",diff);



 [UIView animateWithDuration:0.5

                  animations:^{ 
                    [buttonCaption setFrame:CGRectMake(buttonCaption.frame.origin.x-diff, 
                                                       buttonCaption.frame.origin.y, 
                                                       buttonCaption.frame.size.width + diff, 
                                                       buttonCaption.frame.size.height)];                


                  } 
                  completion:^(BOOL  completed)
                {
[self nextAnimation:stringsize.width];
                }
  ]; 
}   

Answer 1

Try this block animation code

[UIView animateWithDuration:0.5f 
                 animations:^{ 
                     float kOfset = 0.25f;
                     CGFloat newSizeX = buttonCaption.frame.size.width*(1+kOfset);
                     CGFloat ofsetX = buttonCaption.frame.size.width*kOfset;
                     [buttonCaption setFrame:CGRectMake(buttonCaption.frame.origin.x-ofsetX, buttonCaption.frame.origin.y, newSizeX, buttonCaption.frame.size.height)];                
                 }
                 completion:^(BOOL finished){  }];

Change kOfset to value what you want (this is size in %).