我的应用程序使用UITextView。现在我想让UITextView有一个占位符,类似于你可以为UITextField设置的占位符。
如何做到这一点?
我的应用程序使用UITextView。现在我想让UITextView有一个占位符,类似于你可以为UITextField设置的占位符。
如何做到这一点?
当前回答
我遵循了这个链接的代码。只有7个简单的步骤。它添加了一个UILabel的textView和隐藏/显示标签时,文本输入或从textView通过textView的textViewDidChangeSelection(_ textView: UITextView)委托方法。我将步骤放在代码上方的注释中。
// 1. make sure to include the UITextViewDelegate
class YourClass: UITextViewDelegate {
@IBOutlet weak var textView : UITextView!
// 2. create placeholder textLabel
let placeHolderTextLabel: UILabel = {
let placeholderLabel = UILabel()
placeholderLabel.text = "Placeholder text..."
placeholderLabel.sizeToFit()
placeholderLabel.textColor = UIColor.lightGray
return placeholderLabel
}()
override func viewDidLoad() {
super.viewDidLoad()
// 3. set textView delegate
textView.delegate = self
configurePlaceholderTextLabel()
}
func configurePlaceholderTextLabel() {
// 4. add placeholder label to textView, set it's frame and font
textView.addSubview(placeHolderTextLabel)
placeHolderTextLabel.frame.origin = CGPoint(x: 5, y: (textView.font?.pointSize)! / 2)
placeHolderTextLabel.font = UIFont.systemFont(ofSize: (textView.font?.pointSize)!)
// 5. decide wether the placeHolderTextLabel is hidden or not depending on if there is or isn't text inside the textView
placeHolderTextLabel.isHidden = !textView.text.isEmpty
}
// 6. implement textView delegate method to update the placeHolderTextLabel when the text is changed
func textViewDidChangeSelection(_ textView: UITextView) {
// 7. decide wether the placeHolderTextLabel is hidden or not depending on if there is or isn't text inside the textView when text in textView is changed
placeHolderTextLabel.isHidden = !textView.text.isEmpty
}
}
其他回答
我能够做添加一个“占位符”到UITextView与很多少的代码。这就是我所做的:
UITextView *textView = [[UITextView alloc] initWithFrame:CGRectMake(60, 800, 200, 60)];
textView.text = @"Write characters here...";
textView.textColor=[UIColor grayColor];
textView.font = [UIFont fontWithName:@"Hevlatica" size:15];
textView.delegate=self;
我猜这不是一个真正的占位符,因为你必须在写之前删除文本,但如果你想要一些更简单的东西,它可能会有帮助。
我遵循了这个链接的代码。只有7个简单的步骤。它添加了一个UILabel的textView和隐藏/显示标签时,文本输入或从textView通过textView的textViewDidChangeSelection(_ textView: UITextView)委托方法。我将步骤放在代码上方的注释中。
// 1. make sure to include the UITextViewDelegate
class YourClass: UITextViewDelegate {
@IBOutlet weak var textView : UITextView!
// 2. create placeholder textLabel
let placeHolderTextLabel: UILabel = {
let placeholderLabel = UILabel()
placeholderLabel.text = "Placeholder text..."
placeholderLabel.sizeToFit()
placeholderLabel.textColor = UIColor.lightGray
return placeholderLabel
}()
override func viewDidLoad() {
super.viewDidLoad()
// 3. set textView delegate
textView.delegate = self
configurePlaceholderTextLabel()
}
func configurePlaceholderTextLabel() {
// 4. add placeholder label to textView, set it's frame and font
textView.addSubview(placeHolderTextLabel)
placeHolderTextLabel.frame.origin = CGPoint(x: 5, y: (textView.font?.pointSize)! / 2)
placeHolderTextLabel.font = UIFont.systemFont(ofSize: (textView.font?.pointSize)!)
// 5. decide wether the placeHolderTextLabel is hidden or not depending on if there is or isn't text inside the textView
placeHolderTextLabel.isHidden = !textView.text.isEmpty
}
// 6. implement textView delegate method to update the placeHolderTextLabel when the text is changed
func textViewDidChangeSelection(_ textView: UITextView) {
// 7. decide wether the placeHolderTextLabel is hidden or not depending on if there is or isn't text inside the textView when text in textView is changed
placeHolderTextLabel.isHidden = !textView.text.isEmpty
}
}
- (void)textViewDidChange:(UITextView *)textView
{
placeholderLabel.hidden = YES;
}
在textview上放一个标签。
简单地创建UITextView的@IBDesignable子类:
@IBDesignable class AttributedTextView: UITextView {
private let placeholderLabel = UILabel()
@IBInspectable var placeholder: String = "" {
didSet {
setupPlaceholderLabelIfNeeded()
textViewDidChange()
}
}
override var text: String! {
didSet {
textViewDidChange()
}
}
//MARK: - Initialization
override func awakeFromNib() {
super.awakeFromNib()
setupPlaceholderLabelIfNeeded()
NotificationCenter.default.addObserver(self, selector: #selector(textViewDidChange), name: .UITextViewTextDidChange, object: nil)
}
//MARK: - Deinitialization
deinit {
NotificationCenter.default.removeObserver(self)
}
//MARK: - Internal
func textViewDidChange() {
placeholderLabel.isHidden = !text.isEmpty
layoutIfNeeded()
}
//MARK: - Private
private func setupPlaceholderLabelIfNeeded() {
placeholderLabel.removeFromSuperview()
placeholderLabel.frame = CGRect(x: 0, y: 8, width: frame.size.width, height: 0)
placeholderLabel.textColor = UIColor.lightGray
placeholderLabel.text = placeholder
placeholderLabel.sizeToFit()
insertSubview(placeholderLabel, at: 0)
}
}
然后在标识检查器中设置占位符:
简单的Swift 3解决方案
添加UITextViewDelegate到类中
设置你的textview .delegate = self
创建placeholderLabel和位置它在你的textview
现在动画placeholderLabel。alpha在textViewDidChange:
func textViewDidChange(_ textView: UITextView) {
let newAlpha: CGFloat = textView.text.isEmpty ? 1 : 0
if placeholderLabel.alpha != newAlpha {
UIView.animate(withDuration: 0.3) {
self.placeholderLabel.alpha = newAlpha
}
}
}
你可能不得不使用placeholderLabel位置来设置它,但这应该不会太难