问题
I'm trying to add a UISlider to my view programmatically including constraints so that its width adapts to the whole screen width. This is what I got so far:

//2 Add UISlider
self.slider = [[UISlider alloc] init];
[self.view addSubview:self.slider];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:self.slider
attribute:NSLayoutAttributeLeft
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeLeft
multiplier:1
constant:0]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:self.slider
attribute:NSLayoutAttributeRight
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeRight
multiplier:1
constant:0]];
[self.view addConstraint:[NSLayoutConstraint constraintWithItem:self.slider
attribute:NSLayoutAttributeBottom
relatedBy:NSLayoutRelationEqual
toItem:self.view
attribute:NSLayoutAttributeBottom
multiplier:1
constant:0]];
回答1:
Missing self.slider.translatesAutoresizingMaskIntoConstraints = NO;
Your code is working fine for me. See the below image

来源:https://stackoverflow.com/questions/21810358/add-uislider-with-autolayout-programmatically