[英]Width and Height Equal to its superView using autolayout programmatically?
我一直在网上寻找很多片段,但仍然找不到问题的答案。 我的问题是我有一个 scrollView(SV) 并且我想以编程方式在 scrollView(SV) 内添加一个按钮,其超级视图的宽度和高度与 scrollView(SV) 相同,这样当用户旋转设备按钮时,按钮将具有相同的框架滚动视图(SV)。 如何做 NSLayout/NSLayoutConstraint? 谢谢
如果有人正在寻找Swift 解决方案——我会为UIView
创建一个 Swift扩展,它会在你每次想要将子视图框架绑定到它的超级视图边界时为你提供帮助:
斯威夫特 2:
extension UIView {
/// Adds constraints to this `UIView` instances `superview` object to make sure this always has the same size as the superview.
/// Please note that this has no effect if its `superview` is `nil` – add this `UIView` instance as a subview before calling this.
func bindFrameToSuperviewBounds() {
guard let superview = self.superview else {
print("Error! `superview` was nil – call `addSubview(view: UIView)` before calling `bindFrameToSuperviewBounds()` to fix this.")
return
}
self.translatesAutoresizingMaskIntoConstraints = false
superview.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-0-[subview]-0-|", options: .DirectionLeadingToTrailing, metrics: nil, views: ["subview": self]))
superview.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-0-[subview]-0-|", options: .DirectionLeadingToTrailing, metrics: nil, views: ["subview": self]))
}
}
斯威夫特 3:
extension UIView {
/// Adds constraints to this `UIView` instances `superview` object to make sure this always has the same size as the superview.
/// Please note that this has no effect if its `superview` is `nil` – add this `UIView` instance as a subview before calling this.
func bindFrameToSuperviewBounds() {
guard let superview = self.superview else {
print("Error! `superview` was nil – call `addSubview(view: UIView)` before calling `bindFrameToSuperviewBounds()` to fix this.")
return
}
self.translatesAutoresizingMaskIntoConstraints = false
superview.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-0-[subview]-0-|", options: .directionLeadingToTrailing, metrics: nil, views: ["subview": self]))
superview.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-0-[subview]-0-|", options: .directionLeadingToTrailing, metrics: nil, views: ["subview": self]))
}
}
斯威夫特 4.2:
extension UIView {
/// Adds constraints to this `UIView` instances `superview` object to make sure this always has the same size as the superview.
/// Please note that this has no effect if its `superview` is `nil` – add this `UIView` instance as a subview before calling this.
func bindFrameToSuperviewBounds() {
guard let superview = self.superview else {
print("Error! `superview` was nil – call `addSubview(view: UIView)` before calling `bindFrameToSuperviewBounds()` to fix this.")
return
}
self.translatesAutoresizingMaskIntoConstraints = false
self.topAnchor.constraint(equalTo: superview.topAnchor, constant: 0).isActive = true
self.bottomAnchor.constraint(equalTo: superview.bottomAnchor, constant: 0).isActive = true
self.leadingAnchor.constraint(equalTo: superview.leadingAnchor, constant: 0).isActive = true
self.trailingAnchor.constraint(equalTo: superview.trailingAnchor, constant: 0).isActive = true
}
}
然后简单地这样称呼它:
// after adding as a subview, e.g. `view.addSubview(subview)`
subview.bindFrameToSuperviewBounds()
我不确定这是否是最有效的方法,但它有效..
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];
此链接可以帮助您,请按照说明操作: http : //www.raywenderlich.com/20881/beginning-auto-layout-part-1-of-2
编辑 :
使用以下代码片段,其中 subview 是您的 subivew。
[subview setTranslatesAutoresizingMaskIntoConstraints:NO];
[self.view addConstraints:[NSLayoutConstraint
constraintsWithVisualFormat:@"H:|-0-[subview]-0-|"
options:NSLayoutFormatDirectionLeadingToTrailing
metrics:nil
views:NSDictionaryOfVariableBindings(subview)]];
[self.view addConstraints:[NSLayoutConstraint
constraintsWithVisualFormat:@"V:|-0-[subview]-0-|"
options:NSLayoutFormatDirectionLeadingToTrailing
metrics:nil
views:NSDictionaryOfVariableBindings(subview)]];
UIView 的addConstraint
和removeConstraint
方法将被弃用,因此值得使用“约束创建便利”:
view.topAnchor.constraint(equalTo: superView.topAnchor, constant: 0).isActive = true
view.bottomAnchor.constraint(equalTo: superView.bottomAnchor, constant: 0).isActive = true
view.leadingAnchor.constraint(equalTo: superView.leadingAnchor, constant: 0).isActive = true
view.trailingAnchor.constraint(equalTo: superView.trailingAnchor, constant: 0).isActive = true
这是Swift 3+ 中一种更实用的方法,带有先决条件而不是print
(它很容易在控制台中消失)。 这将报告程序员错误作为失败的构建。
将此扩展添加到您的项目中:
extension UIView {
/// Adds constraints to the superview so that this view has same size and position.
/// Note: This fails the build if the `superview` is `nil` – add it as a subview before calling this.
func bindEdgesToSuperview() {
guard let superview = superview else {
preconditionFailure("`superview` was nil – call `addSubview(view: UIView)` before calling `bindEdgesToSuperview()` to fix this.")
}
translatesAutoresizingMaskIntoConstraints = false
["H:|-0-[subview]-0-|", "V:|-0-[subview]-0-|"].forEach { visualFormat in
superview.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: visualFormat, options: .directionLeadingToTrailing, metrics: nil, views: ["subview": self]))
}
}
}
现在简单地这样称呼它:
// after adding as a subview, e.g. `view.addSubview(subview)`
subview.bindEdgesToSuperview()
请注意,上述方法已集成到我的HandyUIKit框架中,该框架还将一些更方便的 UI 助手添加到您的项目中。
如果您在项目中经常使用编程约束,那么我建议您查看SnapKit 。 它使处理约束变得更容易,也更不容易出错。
按照文档中的安装说明将 SnapKit 包含到您的项目中。 然后在 Swift 文件的顶部导入它:
import SnapKit
现在您可以通过以下方式实现相同的目的:
subview.snp.makeConstraints { make in
make.edges.equalToSuperview()
}
斯威夫特 3:
import UIKit
extension UIView {
func bindFrameToSuperviewBounds() {
guard let superview = self.superview else {
print("Error! `superview` was nil – call `addSubview(view: UIView)` before calling `bindFrameToSuperviewBounds()` to fix this.")
return
}
self.translatesAutoresizingMaskIntoConstraints = false
superview.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-0-[subview]-0-|", options: .directionLeadingToTrailing, metrics: nil, views: ["subview": self]))
superview.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-0-[subview]-0-|", options: .directionLeadingToTrailing, metrics: nil, views: ["subview": self]))
}
}
Swift 4使用NSLayoutConstraint
:
footerBoardImageView.translatesAutoresizingMaskIntoConstraints = false
let widthConstraint = NSLayoutConstraint(item: yourview, attribute: NSLayoutAttribute.width, relatedBy: NSLayoutRelation.equal, toItem: superview, attribute: NSLayoutAttribute.width, multiplier: 1, constant: 0)
let heightConstraint = NSLayoutConstraint(item: yourview, attribute: NSLayoutAttribute.height, relatedBy: NSLayoutRelation.equal, toItem: superview, attribute: NSLayoutAttribute.height, multiplier: 1, constant: 0)
superview.addConstraints([widthConstraint, heightConstraint])
作为一个补充答案,对于那些不反对包含第三方库的人来说, PureLayout库提供了一种方法来做到这一点。 安装库后,就像这样简单
myView.autoPinEdgesToSuperviewEdges()
我从其他答案中挑选了最好的元素:
extension UIView {
/// Adds constraints to this `UIView` instances `superview` object to make sure this always has the same size as the superview.
/// Please note that this has no effect if its `superview` is `nil` – add this `UIView` instance as a subview before calling this.
func bindFrameToSuperviewBounds() {
guard let superview = self.superview else {
print("Error! `superview` was nil – call `addSubview(view: UIView)` before calling `bindFrameToSuperviewBounds()` to fix this.")
return
}
self.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
self.topAnchor.constraint(equalTo: superview.topAnchor),
self.bottomAnchor.constraint(equalTo: superview.bottomAnchor),
self.leadingAnchor.constraint(equalTo: superview.leadingAnchor),
self.trailingAnchor.constraint(equalTo: superview.trailingAnchor)
])
}
}
您可以像这样使用它,例如在您的自定义 UIView 中:
let myView = UIView()
myView.backgroundColor = UIColor.red
self.addSubview(myView)
myView.bindFrameToSuperviewBounds()
作为@Dschee 解决方案的后续,这里是 swift 3.0 语法:(请注意:这不是我的解决方案,我刚刚为 Swift 3.0 修复了它)
extension UIView {
/// Adds constraints to this `UIView` instances `superview` object to make sure this always has the same size as the superview.
/// Please note that this has no effect if its `superview` is `nil` – add this `UIView` instance as a subview before calling this.
func bindFrameToSuperviewBounds() {
guard let superview = self.superview else {
print("Error! `superview` was nil – call `addSubview(view: UIView)` before calling `bindFrameToSuperviewBounds()` to fix this.")
return
}
self.translatesAutoresizingMaskIntoConstraints = false
superview.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-0-[subview]-0-|", options: .directionLeadingToTrailing, metrics: nil, views: ["subview": self]))
superview.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-0-[subview]-0-|", options: .directionLeadingToTrailing, metrics: nil, views: ["subview": self]))
}
我需要完全覆盖超级视图。 其他人不会在方向改变期间这样做。 所以我写了一个新的 - 使用 20 的任意大小乘数。随意更改您的需要。 还要注意这个实际上使子视图比父视图大很多,这可能与需求不同。
extension UIView {
func coverSuperview() {
guard let superview = self.superview else {
assert(false, "Error! `superview` was nil – call `addSubview(_ view: UIView)` before calling `\(#function)` to fix this.")
return
}
self.translatesAutoresizingMaskIntoConstraints = false
let multiplier = CGFloat(20.0)
NSLayoutConstraint.activate([
self.heightAnchor.constraint(equalTo: superview.heightAnchor, multiplier: multiplier),
self.widthAnchor.constraint(equalTo: superview.widthAnchor, multiplier: multiplier),
self.centerXAnchor.constraint(equalTo: superview.centerXAnchor),
self.centerYAnchor.constraint(equalTo: superview.centerYAnchor),
])
}
}
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