我一直在网上寻找很多片段,但仍然找不到解决问题的答案。我的问题是我有一个scrollView(SV),我想以编程方式在scrollView(SV)内添加一个按钮,其宽度和高度与它的superview相同,即scrollView(SV),以便用户旋转设备按钮时具有相同的框架scrollView(SV)。如何做NSLayout / NSLayoutConstraint?谢谢
我不确定这是否是最有效的方法,但确实有效。
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom]; button.translatesAutoresizingMaskIntoConstraints = NO; // initialize [coverForScrolView addSubview:button]; NSLayoutConstraint *width =[NSLayoutConstraint constraintWithItem:button attribute:NSLayoutAttributeWidth relatedBy:0 toItem:coverForScrolView attribute:NSLayoutAttributeWidth multiplier:1.0 constant:0]; NSLayoutConstraint *height =[NSLayoutConstraint constraintWithItem:button attribute:NSLayoutAttributeHeight relatedBy:0 toItem:coverForScrolView attribute:NSLayoutAttributeHeight multiplier:1.0 constant:0]; NSLayoutConstraint *top = [NSLayoutConstraint constraintWithItem:button attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:coverForScrolView attribute:NSLayoutAttributeTop multiplier:1.0f constant:0.f]; NSLayoutConstraint *leading = [NSLayoutConstraint constraintWithItem:button attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:coverForScrolView attribute:NSLayoutAttributeLeading multiplier:1.0f constant:0.f]; [coverForScrolView addConstraint:width]; [coverForScrolView addConstraint:height]; [coverForScrolView addConstraint:top]; [coverForScrolView addConstraint:leading];