TextField 前面带一个 Icon 的Custom View 实现

IconTextField.swift

//
//  IconTextField.swift
//  ExamTimePickerDemo
//
//  Created by Haizhen Lee on 15/5/29.
//  Copyright (c) 2015年 banxi1988. All rights reserved.
// 以下用到的一些 AutoLayout的自定义封装方法见
// https://gist.github.com/banxi1988/8b07212cadaddd28384f

import UIKit

@IBDesignable
class IconTextField: UIView {
    
    let iconImageView = UIImageView(frame: CGRectZero)
    let textField = UITextField(frame: CGRectZero)
    let iconPadding :CGFloat = 15
    let padding = UIEdgeInsets(top: 4, left: 15, bottom: 4, right: 15)
    
    func commonInit(){
        addSubview(iconImageView)
        addSubview(textField)
       
        iconImageView.setTranslatesAutoresizingMaskIntoConstraints(false)
        iconImageView.pinCenterY()
        iconImageView.pinLeading(padding:padding.left)
        iconImageView.contentMode = UIViewContentMode.ScaleAspectFit
       
        textField.setTranslatesAutoresizingMaskIntoConstraints(false)
        textField.setContentHuggingPriority(240, forAxis: UILayoutConstraintAxis.Horizontal)
        textField.pinCenterY()
        textField.pinLeadingToSibling(iconImageView, withMargin: iconPadding)
        textField.pinTrailing(padding:padding.right)
       
        textField.textAlignment = .Left
        invalidateIntrinsicContentSize()
    }
  
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        commonInit()
    }
    
    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        commonInit()
    }
   
    override func prepareForInterfaceBuilder() {
        super.prepareForInterfaceBuilder()
        let bundle = NSBundle(forClass: self.dynamicType)
        let image = UIImage(named: "icon_locate", inBundle: bundle, compatibleWithTraitCollection: self.traitCollection)
        iconImageView.image = image
        textField.text = "大学英语四级"
        backgroundColor = UIColor.lightGrayColor()
    }

    override func intrinsicContentSize() -> CGSize {
        let iconSize = iconImageView.intrinsicContentSize()
        let textSize = textField.intrinsicContentSize()
        
        let width  = padding.left + iconSize.width + iconPadding + textSize.width + padding.right
        let height = padding.top + max(iconSize.height, textSize.height) + padding.bottom
        return CGSize(width: width, height: height)
    }
    
}