我只是在摆弄 AutoLayout(使用代码),遇到了一些我不太了解的东西。我做了一个简单的例子来演示这个问题:
- (void)viewDidLoad
{
[super viewDidLoad];
//create views
UIView *redView = [UIView new];
redView.backgroundColor = [UIColor redColor];
redView.translatesAutoresizingMaskIntoConstraints = NO;
UIView *blueView = [UIView new];
blueView.backgroundColor = [UIColor blueColor];
blueView.translatesAutoresizingMaskIntoConstraints = NO;
//add views to viewcontroller's view
[self.view addSubview:redView];
[self.view addSubview:blueView];
//add contraints
NSDictionary *views = NSDictionaryOfVariableBindings(redView, blueView);
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-[redView]-|" options:0 metrics:nil views:views]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-[blueView]-|" options:0 metrics:nil views:views]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-[redView]-[blueView]-|" options:0 metrics:nil views:views]];
}
我希望得到以下结果:http: //i.stack.imgur.com/LCWQP.png
但相反,它给出了以下结果:http: //i.stack.imgur.com/DJK5i.png
现在,我知道它可以通过使用来解决[NSLayoutConstraint constraintWithItem: attribute: relatedBy: toItem: attribute: multiplier: constant: ]
,但我想知道是否有一个 VisualFormat 选项,或者我的代码中缺少一些东西......
提前感谢您在我的学习过程中的帮助!