I'm using autolayout to change the height of my scrollview. I add some subviews to the scrollview where I manually increment the content size. But when I get an event where I am about to change the height the content size is zero.
Here is the code:
-(void) addTag:(NSString *)tagName {
...
[button addTarget:self action:@selector(tagPressed:) forControlEvents:UIControlEventTouchUpInside];
[self setContentSize:CGSizeMake(self.frame.size.width, self.contentSize.height+60)];
[self.items addObject: button];
NSLog(@"content height: %0.2f", self.contentSize.height);
}
Console Output:
2013-04-18 18:23:06.106 TouchSelectApp[19944:c07] content height: 120.00
Here I output the contentSize :
- (void)tagPressed:(UIButton *)sender {
NSLog(@"1 content height: %0.2f", self.contentSize.height);
...
}
The console shows:
2013-04-18 18:17:24.747 TouchSelectApp[19944:c07] 1 content height: 0.00
I don't why the content height is set to zero. Help Me!
Update: Here is the problem I am trying to solve.
I am have a scroll view with buttons. Initially it only shows one button. When the button is pressed tagPressed: is called. Tag Pressed changes the height to show all the buttons. Then when the user selects a button the scrollview's height is changed to the original and the offset is set to the button's origin. The below code works but the animation is all wrong. If I change the offset and before the animation block then it just sets the offset to zero.
- (void)tagPressed:(UIButton *)sender {
CGPoint p;
float maxHeight = self.items.count * 60;
if (self.height.constant == maxHeight) {
self.height.constant = 60;
p = CGPointMake(0, sender.frame.origin.y-5);
}else {
self.height.constant = maxHeight;
p = CGPointMake(0, 0);
}
[self.superview setNeedsUpdateConstraints];
[UIView animateWithDuration:0.5f animations: ^{
[self.superview layoutIfNeeded];
} completion:^(BOOL finished) {
[self setContentOffset:p];
}];
}