问题描述
我一直无法弄清楚如何解决我的这个问题。我试图遵循这篇文章的答案。 How to change UIView height based on elements inside it
就像帖子回答说的那样，我有：
- 在 UIContainerView 顶部到 UITextView 顶部和 UIContainerView 底部到 UITextView 底部之间设置自动布局约束 (#1)
- 在文本视图上设置高度约束 (#2) 并在调整文本视图大小时更改其常量 (#3)
我必须以编程方式完成这一切。我首先为容器视图设置框架并给它一个指定的高度。我不确定这是否也可以。我还在 viewDidLoad 中添加了 (#1)，但不确定这是否正确。
文本视图无法在当前约束下增加高度（如果我删除 topAnchor 约束但容器视图仍然不会改变大小，它可以增加）。
class ChatController: UICollectionViewController,UICollectionViewDelegateFlowLayout,UIImagePickerControllerDelegate,UINavigationControllerDelegate {
lazy var containerView: UIView = {
let containerView = UIView()
containerView.translatesAutoresizingMaskIntoConstraints = false
containerView.frame = CGRect(x: 0,y: 0,width: self.view.frame.width,height: self.view.frame.height * 0.075)
return containerView
}()
lazy var textView: UITextView = {
let textView = UITextView()
textView.text = "Enter message..."
textView.isScrollEnabled = false
textView.translatesAutoresizingMaskIntoConstraints = false
textView.delegate = self
return textView
}()
override func viewDidLoad() {
super.viewDidLoad()
...
textViewDidChange(self.textView)
addContainerSubViews()
(#1)
containerView.topAnchor.constraint(equalTo: self.textView.topAnchor,constant: -UIScreen.main.bounds.size.height * 0.075 * 0.2).isActive = true
containerView.bottomAnchor.constraint(equalTo: self.textView.bottomAnchor,constant: UIScreen.main.bounds.size.height * 0.075 * 0.2).isActive = true
}
func addContainerSubViews() {
let height = UIScreen.main.bounds.size.height
let width = UIScreen.main.bounds.size.width
let containerHeight = height * 0.075
...//constraints for imageView and sendButton...
containerView.addSubview(self.textView)
self.textView.leftAnchor.constraint(equalTo: imageView.rightAnchor,constant: width/20).isActive = true
self.textView.rightAnchor.constraint(equalTo: sendButton.leftAnchor,constant: -width/20).isActive = true
(#2)
self.textView.heightAnchor.constraint(equalToConstant: containerHeight * 0.6).isActive = true
}
override var inputAccessoryView: UIView? {
get {
return containerView
}
}
(#3)
func textViewDidChange(_ textView: UITextView) {
let size = CGSize(width: view.frame.width,height: .infinity)
let estimatedSize = textView.sizeThatFits(size)
textView.constraints.forEach { (constraint) in
if constraint.firstAttribute == .height {
constraint.constant = estimatedSize.height
}
}
}
解决方法
您可以使用自动布局/约束来完成这一切。由于禁用滚动的 UITextView 将根据文本“自动调整”其高度，因此无需计算高度并更改约束常量。
这是一个例子——它来自上一个答案，修改为包含您的图像视图和发送按钮：
class ViewController: UIViewController {
let testLabel: InputLabel = InputLabel()
override func viewDidLoad() {
super.viewDidLoad()
let instructionLabel = UILabel()
instructionLabel.textAlignment = .center
instructionLabel.text = "Tap yellow label to edit..."
let centeringFrameView = UIView()
// label properties
let fnt: UIFont = .systemFont(ofSize: 32.0)
testLabel.isUserInteractionEnabled = true
testLabel.font = fnt
testLabel.adjustsFontSizeToFitWidth = true
testLabel.minimumScaleFactor = 0.25
testLabel.numberOfLines = 2
testLabel.setContentHuggingPriority(.required,for: .vertical)
let minLabelHeight = ceil(fnt.lineHeight)
// so we can see the frames
centeringFrameView.backgroundColor = .red
testLabel.backgroundColor = .yellow
[centeringFrameView,instructionLabel,testLabel].forEach {
$0.translatesAutoresizingMaskIntoConstraints = false
}
view.addSubview(instructionLabel)
view.addSubview(centeringFrameView)
centeringFrameView.addSubview(testLabel)
let g = view.safeAreaLayoutGuide
NSLayoutConstraint.activate([
// instruction label centered at top
instructionLabel.topAnchor.constraint(equalTo: g.topAnchor,constant: 20.0),instructionLabel.centerXAnchor.constraint(equalTo: g.centerXAnchor),// centeringFrameView 20-pts from instructionLabel bottom
centeringFrameView.topAnchor.constraint(equalTo: instructionLabel.bottomAnchor,// Leading / Trailing with 20-pts "padding"
centeringFrameView.leadingAnchor.constraint(equalTo: g.leadingAnchor,centeringFrameView.trailingAnchor.constraint(equalTo: g.trailingAnchor,constant: -20.0),// test label centered vertically in centeringFrameView
testLabel.centerYAnchor.constraint(equalTo: centeringFrameView.centerYAnchor,constant: 0.0),// Leading / Trailing with 20-pts "padding"
testLabel.leadingAnchor.constraint(equalTo: centeringFrameView.leadingAnchor,testLabel.trailingAnchor.constraint(equalTo: centeringFrameView.trailingAnchor,// height will be zero if label has no text,// so give it a min height of one line
testLabel.heightAnchor.constraint(greaterThanOrEqualToConstant: minLabelHeight),// centeringFrameView height = 3 * minLabelHeight
centeringFrameView.heightAnchor.constraint(equalToConstant: minLabelHeight * 3.0)
])
// to handle user input
testLabel.editCallBack = { [weak self] str in
guard let self = self else { return }
self.testLabel.text = str
}
testLabel.doneCallBack = { [weak self] in
guard let self = self else { return }
// do something when user taps done / enter
}
let t = UITapGestureRecognizer(target: self,action: #selector(self.labelTapped(_:)))
testLabel.addGestureRecognizer(t)
}
@objc func labelTapped(_ g: UITapGestureRecognizer) -> Void {
testLabel.becomeFirstResponder()
testLabel.inputContainerView.theTextView.text = testLabel.text
testLabel.inputContainerView.theTextView.becomeFirstResponder()
}
}
class InputLabel: UILabel {
var editCallBack: ((String) -> ())?
var doneCallBack: (() -> ())?
override var canBecomeFirstResponder: Bool {
return true
}
override var canResignFirstResponder: Bool {
return true
}
override var inputAccessoryView: UIView? {
get { return inputContainerView }
}
lazy var inputContainerView: CustomInputAccessoryView = {
let v = CustomInputAccessoryView()
v.editCallBack = { [weak self] str in
guard let self = self else { return }
self.editCallBack?(str)
}
v.doneCallBack = { [weak self] in
guard let self = self else { return }
self.resignFirstResponder()
}
return v
}()
}
class CustomInputAccessoryView: UIView,UITextViewDelegate {
var editCallBack: ((String) -> ())?
var doneCallBack: (() -> ())?
let theTextView: UITextView = {
let tv = UITextView()
tv.isScrollEnabled = false
tv.font = .systemFont(ofSize: 16)
tv.autocorrectionType = .no
tv.returnKeyType = .done
return tv
}()
let imgView: UIImageView = {
let v = UIImageView()
v.contentMode = .scaleAspectFit
v.clipsToBounds = true
return v
}()
let sendButton: UIButton = {
let v = UIButton()
return v
}()
override init(frame: CGRect) {
super.init(frame: frame)
backgroundColor = .lightGray
autoresizingMask = [.flexibleHeight,.flexibleWidth]
if let img = UIImage(named: "testImage") {
imgView.image = img
} else {
imgView.backgroundColor = .systemBlue
}
let largeConfig = UIImage.SymbolConfiguration(pointSize: 22,weight: .regular,scale: .large)
let buttonImg = UIImage(systemName: "paperplane.fill",withConfiguration: largeConfig)
sendButton.setImage(buttonImg,for: .normal)
[theTextView,imgView,sendButton].forEach { v in
addSubview(v)
v.translatesAutoresizingMaskIntoConstraints = false
}
// if we want to see the image view and button frames
//[imgView,sendButton].forEach { v in
// v.backgroundColor = .systemYellow
//}
NSLayoutConstraint.activate([
// constrain image view 40x40 with 8-pts leading
imgView.widthAnchor.constraint(equalToConstant: 40.0),imgView.heightAnchor.constraint(equalTo: imgView.widthAnchor),imgView.leadingAnchor.constraint(equalTo: leadingAnchor,constant: 8.0),// constrain image view 40x40 with 8-pts trailing
sendButton.widthAnchor.constraint(equalToConstant: 40.0),sendButton.heightAnchor.constraint(equalTo: sendButton.widthAnchor),sendButton.trailingAnchor.constraint(equalTo: trailingAnchor,constant: -8.0),// constrain text view with 10-pts from
// image view trailing
// send button leading
theTextView.leadingAnchor.constraint(equalTo: imgView.trailingAnchor,constant: 10),theTextView.trailingAnchor.constraint(equalTo: sendButton.leadingAnchor,constant: -10),// constrain image view and button
// centered vertically
// at least 8-pts top and bottom
imgView.centerYAnchor.constraint(equalTo: centerYAnchor),sendButton.centerYAnchor.constraint(equalTo: centerYAnchor),imgView.topAnchor.constraint(greaterThanOrEqualTo: topAnchor,sendButton.topAnchor.constraint(greaterThanOrEqualTo: topAnchor,imgView.bottomAnchor.constraint(lessThanOrEqualTo: bottomAnchor,sendButton.bottomAnchor.constraint(lessThanOrEqualTo: bottomAnchor,// constrain text view 8-pts top/bottom
theTextView.topAnchor.constraint(equalTo: topAnchor,theTextView.bottomAnchor.constraint(equalTo: bottomAnchor,])
theTextView.delegate = self
}
func textView(_ textView: UITextView,shouldChangeTextIn range: NSRange,replacementText text: String) -> Bool {
if (text == "\n") {
textView.resignFirstResponder()
doneCallBack?()
}
return true
}
func textViewDidChange(_ textView: UITextView) {
editCallBack?(textView.text ?? "")
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override var intrinsicContentSize: CGSize {
return .zero
}
}
输出：
