ios - 以编程方式使用 Autolayout 添加 UISLider

Question

我正在尝试以编程方式向我的 View 添加一个 UISlider，包括约束，以便它的宽度适应整个屏幕宽度。这是我到目前为止得到的:

//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]];

Answer 1

缺少 self.slider.translatesAutoresizingMaskIntoConstraints = NO; 您的代码对我来说工作正常。见下图