Swift自定义View和OC自定义View的原理都是一样的，重写init()方法或initWithFrame()方法，下面简单说说如何自定义swift UIView
主要是重写init（frame：CGRect)方法，其中required init?(coder aDecoder: NSCoder) 是必不可少的，swift语言强制要求的
//
// LoginImgFieldView.swift
// SmartMilk
//
// Created by mac on 2017/6/9.
// Copyright © 2017年 mac. All rights reserved.
//
import UIKit
let G_HEADIMAGE_HEIGHT:CGFloat = 30
class LoginImgFieldView: UIView {
var headImgView:UIImageView?
var field:UITextField?
var line:UILabel?
/*
// Only override draw() if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
override func draw(_ rect: CGRect) {
// Drawing code
}
*/
// override init(){
// super.init()
// setupSubViews()
// }
override init(frame:CGRect){
super.init(frame: frame)
setupSubViews()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func setupSubViews() {
let frame = self.bounds
//uiimageVIew
headImgView = UIImageView(frame:CGRect(x:0,y:0,width:G_HEADIMAGE_HEIGHT,height:G_HEADIMAGE_HEIGHT))
headImgView?.backgroundColor = UIColor.blue
//uiTextField
field = UITextField(frame:CGRect(x:0,y:0,width:100,height:G_HEADIMAGE_HEIGHT))
// field?.font = UIFont.systemFont(ofSize: 15)
//uiLabel
line = UILabel(frame: CGRect(x:0,y:frame.size.height-1,width:frame.size.width,height:1))
line?.backgroundColor = UIColor.orange
self.addSubview(headImgView!)
self.addSubview(field!)
self.addSubview(line!)
}
override func layoutSubviews() {
super.layoutSubviews()
let frame = self.bounds
let imgY = (frame.size.height - G_HEADIMAGE_HEIGHT)/2
headImgView?.frame = CGRect(x:0,y:imgY,width:G_HEADIMAGE_HEIGHT,height:G_HEADIMAGE_HEIGHT)
//field
let fieldx = G_HEADIMAGE_HEIGHT+5
let fieldWidth = frame.size.width - fieldx
field?.frame = CGRect(x: fieldx, y: imgY, width: fieldWidth, height: G_HEADIMAGE_HEIGHT)
//label
var lineFrame = line?.frame
lineFrame?.origin.y = frame.size.height - 2
lineFrame?.size.width = frame.size.width
line?.frame = lineFrame!
}
}