Swift之设置UItextField的占位文字颜色颜色

第一步

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第二步

Snip20180328_36.png

import UIKit

class LYWTextField: UITextField {

    let LYWPlaceholderLabelKey = "_placeholderLabel.textColor"
    override func awakeFromNib() {
        super.awakeFromNib()
        var count:UInt32 = 0
        let vars = class_copyIvarList(UITextField.self, &count)

        for i in 0..<count {
            let ivar = vars![Int(i)]
            print("\(String(describing: ivar_getName(ivar)))")

        }

        tintColor = textColor
        _ = resignFirstResponder()

    }

    override func becomeFirstResponder() -> Bool {
        self.setValue(textColor, forKeyPath: LYWPlaceholderLabelKey)
        return super.becomeFirstResponder()
    }

    override func resignFirstResponder() -> Bool {
        self.setValue(UIColor.gray, forKeyPath: LYWPlaceholderLabelKey)
        return super.resignFirstResponder()
    }

}

使用

Snip20180328_37.png

效果 文本框成为第一响应者时候，就是光标聚集，这个时候，占位文字颜色变成了红色

Snip20180328_38.png

为了对比：可以看下面原始的模样

Snip20180328_39.png

效果

Snip20180328_40.png

Demo :https://gitee.com/lanyingwei/codes/9i4fvetq67x3j0zhpsdlc41