如何在UITextView中添加占位符,类似于你可以为UITextField设置的占位符,在Swift中?
当前回答
我知道这是一个老问题,但想分享我认为是一个有用的方式扩展UITextView有placeholderText和placeholderColor字段。基本上你将UITextView转换为UITextField,然后设置attributedPlaceholder字段。PlaceholderText和placeholderColor是IBInspectable字段,所以它们的值可以在IB中设置,并与UITextField占位符功能完全相同。
UITextView+Extend.h
#import <UIKit/UIKit.h>
@interface UITextView (Extend)
@property (nonatomic) IBInspectable NSString *placeholderText;
@property (nonatomic) IBInspectable UIColor *placeholderColor;
@end
UITextView+Extend.m
#import "UITextView+Extend.h"
#import "objc/runtime.h"
@implementation UITextView (Extend)
- (void)setPlaceholderText:(NSString *)placeholderText
{
objc_setAssociatedObject(self, @selector(placeholderText), placeholderText, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
[self updatePlaceholderText];
}
- (NSString*)placeholderText
{
return objc_getAssociatedObject(self, @selector(placeholderText));
}
- (void)setPlaceholderColor:(UIColor *)placeholderColor
{
objc_setAssociatedObject(self, @selector(placeholderColor), placeholderColor, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
[self updatePlaceholderText];
}
- (UIColor*)placeholderColor
{
return objc_getAssociatedObject(self, @selector(placeholderColor));
}
- (void)updatePlaceholderText
{
NSString *text = self.placeholderText;
UIColor *color = self.placeholderColor;
if(text && color)
{
UITextField *textField = (UITextField*)self;
textField.attributedPlaceholder = [[NSAttributedString alloc] initWithString:text attributes:@{NSForegroundColorAttributeName:color}];
}
}
@end
其他回答
不,没有任何占位符可用的textview。你必须把标签上面,当用户进入textview,然后隐藏它或设置默认值时,用户输入删除所有值。
Swift -我写了一个继承了UITextView的类,并添加了一个UILabel作为子视图作为占位符。
import UIKit
@IBDesignable
class HintedTextView: UITextView {
@IBInspectable var hintText: String = "hintText" {
didSet{
hintLabel.text = hintText
}
}
private lazy var hintLabel: UILabel = {
let label = UILabel()
label.font = UIFont.systemFontOfSize(16)
label.textColor = UIColor.lightGrayColor()
label.translatesAutoresizingMaskIntoConstraints = false
return label
}()
override init(frame: CGRect, textContainer: NSTextContainer?) {
super.init(frame: frame, textContainer: textContainer)
setupView()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
setupView()
}
override func prepareForInterfaceBuilder() {
super.prepareForInterfaceBuilder()
setupView()
}
private func setupView() {
translatesAutoresizingMaskIntoConstraints = false
delegate = self
font = UIFont.systemFontOfSize(16)
addSubview(hintLabel)
NSLayoutConstraint.activateConstraints([
hintLabel.leftAnchor.constraintEqualToAnchor(leftAnchor, constant: 4),
hintLabel.rightAnchor.constraintEqualToAnchor(rightAnchor, constant: 8),
hintLabel.topAnchor.constraintEqualToAnchor(topAnchor, constant: 4),
hintLabel.heightAnchor.constraintEqualToConstant(30)
])
}
override func layoutSubviews() {
super.layoutSubviews()
setupView()
}
}
我们可以很容易地实现textview占位符,如果我们正在使用pod IQKeyboardManagerSwift在我们的项目中,只需遵循4个步骤
我们必须将类IQTextView分配给我们的TextView类。 我们必须在Controller页面中导入IQKeyboardManagerSwift 最后但并非最不重要的是,在控制器页面的textView的出口//如果你想:) 通过storyboard inspectable给textView一些占位符文本
Swift 4、4.2和5
[![@IBOutlet var detailTextView: UITextView!
override func viewDidLoad() {
super.viewDidLoad()
detailTextView.delegate = self
}
extension ContactUsViewController : UITextViewDelegate {
public func textViewDidBeginEditing(_ textView: UITextView) {
if textView.text == "Write your message here..." {
detailTextView.text = ""
detailTextView.textColor = UIColor.init(red: 0/255, green: 0/255, blue: 0/255, alpha: 0.86)
}
textView.becomeFirstResponder()
}
public func textViewDidEndEditing(_ textView: UITextView) {
if textView.text == "" {
detailTextView.text = "Write your message here..."
detailTextView.textColor = UIColor.init(red: 0/255, green: 0/255, blue: 0/255, alpha: 0.30)
}
textView.resignFirstResponder()
}
[![}][1]][1]
没有这样的属性在ios添加占位符直接在TextView,而你可以添加一个标签和显示/隐藏在TextView的变化。SWIFT 2.0,确保实现textviewdelegate
func textViewDidChange(TextView: UITextView)
{
if txtShortDescription.text == ""
{
self.lblShortDescription.hidden = false
}
else
{
self.lblShortDescription.hidden = true
}
}
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