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UITextView添加Placeholder(swift)

时间:2015-03-11 23:33:15      阅读:371      评论:0      收藏:0      [点我收藏+]

标签:ios

UITextView添加Placeholder(swift)

by 伍雪颖

添加UILabel并初始化
public let placeholderLabel: UILabel = UILabel()
@IBInspectable public var placeholder: String = "" {
        didSet {
            placeholderLabel.text = placeholder
        }
    }
    
@IBInspectable public var placeholderColor: UIColor = UIColor(red: 0.0, green: 0.0, blue: 0.0980392, alpha: 0.22) {
        didSet {
            placeholderLabel.textColor = placeholderColor
        }
    }
override public var font: UIFont! {
        didSet {
            placeholderLabel.font = font
        }
    }
    
override public var textAlignment: NSTextAlignment {
        didSet {
            placeholderLabel.textAlignment = textAlignment
        }
    }
addSubview添加上去
override init(frame: CGRect, textContainer: NSTextContainer?) {
        super.init(frame: frame, textContainer: textContainer)
        commonInit()
    }
    
    required public init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        commonInit()
    }
    
    func commonInit() {
        NSNotificationCenter.defaultCenter().addObserver(self,
            selector: "textDidChange",
            name: UITextViewTextDidChangeNotification,
            object: nil)
        
        placeholderLabel.font = font
        placeholderLabel.textColor = placeholderColor
        placeholderLabel.textAlignment = textAlignment
        placeholderLabel.text = placeholder
        placeholderLabel.numberOfLines = 0
        placeholderLabel.backgroundColor = UIColor.clearColor()
        placeholderLabel.setTranslatesAutoresizingMaskIntoConstraints(false)
        addSubview(placeholderLabel)
    }

输入文字消失的事件
override public var text: String! {
        didSet {
            textDidChange()
        }
    }

func textDidChange() {
        placeholderLabel.hidden = !text.isEmpty
    }



UITextView添加Placeholder(swift)

标签:ios

原文地址:http://blog.csdn.net/rainlesvio/article/details/44205421

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