Swift - 自定义单元格实现微信聊天界面

1，下面是一个放微信聊天界面的消息展示列表，实现的功能有：

（1）消息可以是文本消息也可以是图片消息

（2）消息背景为气泡状图片，同时消息气泡可根据内容自适应大小

（3）每条消息旁边有头像，在左边表示发送方，在右边表示接收方

2，实现思路

（1）需要定义一个数据结构保存消息内容 MessageItem

（2）继承UITableViewCell实现自定义单元格，这里面放入头像和消息体

（3）继承UITableView实现自定义表格，通过读取数据源，进行页面的渲染

（4）消息体根据内容类型不同，用不同的展示方法

（5）每个单元格的高度需要根据内容计算出来

（6）数据由ViewController来提供初始化数据

3，效果图

4，代码结构

5，主要代码

（1）主页面 ViewController.swift

 import UIKit
class ViewController: UIViewController, ChatDataSource {
     
    var Chats:Array<MessageItem>!
    var tableView:TableView!
     
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
         
        setupChatTable()
    }
     
    /*创建表格及数据*/
    func setupChatTable()
    {
        self.tableView = TableView(frame:CGRectMake(0, 20,
            self.view.frame.size.width, self.view.frame.size.height - 20))
         
        //创建一个重用的单元格
        self.tableView!.registerClass(TableViewCell.self, forCellReuseIdentifier: "MsgCell")
         
        var me = "xiaoming.png"
         
        var you = "xiaohua.png"
         
        var first =  MessageItem(body:"嘿，这张照片咋样，我周末拍的呢！", logo:me,
            date:NSDate(timeIntervalSinceNow:-600), mtype:ChatType.Mine)
         
         
        var second =  MessageItem(image:UIImage(named:"luguhu.jpeg")!,logo:me,
            date:NSDate(timeIntervalSinceNow:-290), mtype:ChatType.Mine)
         
        var third =  MessageItem(body:"太赞了，我也想去那看看呢！",logo:you,
            date:NSDate(timeIntervalSinceNow:-60), mtype:ChatType.Someone)
         
         var fouth =  MessageItem(body:"嗯，下次我们一起去吧！",logo:me,
            date:NSDate(timeIntervalSinceNow:-20), mtype:ChatType.Mine)
         
        var fifth =  MessageItem(body:"好的，一定！",logo:you,
            date:NSDate(timeIntervalSinceNow:0), mtype:ChatType.Someone)
         
        Chats = [first,second, third, fouth, fifth]
         
        self.tableView.chatDataSource = self
         
     
        self.tableView.reloadData()
         
        self.view.addSubview(self.tableView)
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    /*返回对话记录中的全部行数*/
    func rowsForChatTable(tableView:TableView) -> Int
    {
        return self.Chats.count
    }
     
    /*返回某一行的内容*/
    func chatTableView(tableView:TableView, dataForRow row:Int) -> MessageItem
    {
        return Chats[row]
    }
}

（2）消息体数据结构 MessageItem.swift

 import UIKit
//消息类型，我的还是别人的
enum ChatType
{
    case Mine
    case Someone
}
class MessageItem
{
    //头像
    var logo:String
    //消息时间
    var date:NSDate
    //消息类型
    var mtype:ChatType
    //内容视图，标签或者图片
    var view:UIView
    //边距
    var insets:UIEdgeInsets
     
    //设置我的文本消息边距
    class func getTextInsetsMine() -> UIEdgeInsets
    {
        return UIEdgeInsets(top:5, left:10, bottom:11, right:17)
    }
     
    //设置他人的文本消息边距
    class func getTextInsetsSomeone() -> UIEdgeInsets
    {
        return UIEdgeInsets(top:5, left:15, bottom:11, right:10)
    }
     
    //设置我的图片消息边距
    class func getImageInsetsMine() -> UIEdgeInsets
    {
        return UIEdgeInsets(top:11, left:13, bottom:16, right:22)
    }
     
    //设置他人的图片消息边距
    class func getImageInsetsSomeone() -> UIEdgeInsets
    {
        return UIEdgeInsets(top:11, left:13, bottom:16, right:22)
    }
     
    //构造文本消息体
    convenience init(body:NSString, logo:String, date:NSDate, mtype:ChatType)
    {
        var font =  UIFont.boldSystemFontOfSize(12)
         
        var width =  225, height = 10000.0
         
        var atts =  NSMutableDictionary()
        atts.setObject(font,forKey:NSFontAttributeName)
         
        var size =  body.boundingRectWithSize(CGSizeMake(CGFloat(width), CGFloat(height)),
            options:NSStringDrawingOptions.UsesLineFragmentOrigin, attributes:atts, context:nil)
         
        var label =  UILabel(frame:CGRectMake(0, 0, size.size.width, size.size.height))
         
        label.numberOfLines = 0
        label.lineBreakMode = NSLineBreakMode.ByWordWrapping
        label.text = (body.length != 0 ? body : "")
        label.font = font
        label.backgroundColor = UIColor.clearColor()
         
        var insets:UIEdgeInsets =  (mtype == ChatType.Mine ?
            MessageItem.getTextInsetsMine() : MessageItem.getTextInsetsSomeone())
         
        self.init(logo:logo, date:date, mtype:mtype, view:label, insets:insets)
    }
     
    //可以传入更多的自定义视图
    init(logo:String, date:NSDate, mtype:ChatType, view:UIView, insets:UIEdgeInsets)
    {
        self.view = view
        self.logo = logo
        self.date = date
        self.mtype = mtype
        self.insets = insets
    }
     
    //构造图片消息体
    convenience init(image:UIImage, logo:String,  date:NSDate, mtype:ChatType)
    {
        var size = image.size
        //等比缩放
        if (size.width > 220)
        {
            size.height /= (size.width / 220);
            size.width = 220;
        }
        var imageView = UIImageView(frame:CGRectMake(0, 0, size.width, size.height))
        imageView.image = image
        imageView.layer.cornerRadius = 5.0
        imageView.layer.masksToBounds = true
         
        var insets:UIEdgeInsets =  (mtype == ChatType.Mine ?
            MessageItem.getImageInsetsMine() : MessageItem.getImageInsetsSomeone())
         
        self.init(logo:logo,  date:date, mtype:mtype, view:imageView, insets:insets)
    }    
}

（3）表格数据协议 ChatDataSource.swift

 import Foundation
/*
  数据提供协议
*/
protocol ChatDataSource
{   
    /*返回对话记录中的全部行数*/
    func rowsForChatTable( tableView:TableView) -> Int
    /*返回某一行的内容*/
    func chatTableView(tableView:TableView, dataForRow:Int)-> MessageItem
}

（4）自定义表格 TableView.swift

 import UIKit
class TableView:UITableView,UITableViewDelegate, UITableViewDataSource
{
    //用于保存所有消息
    var bubbleSection:Array<MessageItem>!
    //数据源，用于与 ViewController 交换数据
    var chatDataSource:ChatDataSource!
     
    required init(coder aDecoder: NSCoder) {
        
        super.init(coder: aDecoder)
    }
     
    override init(frame:CGRect)
    {
        self.bubbleSection = Array<MessageItem>()
         
        super.init(frame:frame,  style:UITableViewStyle.Grouped)
         
        self.backgroundColor = UIColor.clearColor()
         
        self.separatorStyle = UITableViewCellSeparatorStyle.None
        self.delegate = self
        self.dataSource = self
         
         
    }
     
    override func reloadData()
    {
         
        self.showsVerticalScrollIndicator = false
        self.showsHorizontalScrollIndicator = false
         
        var count =  0
        if ((self.chatDataSource != nil))
        {
            count = self.chatDataSource.rowsForChatTable(self)
             
            if(count > 0)
            {   
                 
                for (var i = 0; i < count; i++)
                {
                     
                    var object =  self.chatDataSource.chatTableView(self, dataForRow:i)
                    bubbleSection.append(object)
                     
                }
                 
                //按日期排序方法
                bubbleSection.sort({$0.date.timeIntervalSince1970 < $1.date.timeIntervalSince1970})
            }
        }
        super.reloadData()
    }
     
    //第一个方法返回分区数，在本例中，就是1
    func numberOfSectionsInTableView(tableView:UITableView)->Int
    {
        return 1
    }
     
    //返回指定分区的行数
    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int
    {
        if (section >= self.bubbleSection.count)
        {
            return 1
        }
         
        return self.bubbleSection.count+1
    }
         
    //用于确定单元格的高度，如果此方法实现得不对，单元格与单元格之间会错位
    func tableView(tableView:UITableView,heightForRowAtIndexPath indexPath:NSIndexPath) -> CGFloat
    {
         
        // Header
        if (indexPath.row == 0)
        {
            return 30.0
        }
         
        var data =  self.bubbleSection[indexPath.row - 1]
         
        return max(data.insets.top + data.view.frame.size.height + data.insets.bottom, 52)
    }
     
    //返回自定义的 TableViewCell
    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath)
        -> UITableViewCell
    {
           
        var cellId = "MsgCell"
        if(indexPath.row > 0)
        {
            var data =  self.bubbleSection[indexPath.row-1]
         
            var cell =  TableViewCell(data:data, reuseIdentifier:cellId)
         
            return cell
        }
        else
        {
             
            return UITableViewCell(style: UITableViewCellStyle.Default, reuseIdentifier: cellId)
        }
    }
}

（5）自定义单元格 TableViewCell.swift

 import UIKit
class TableViewCell:UITableViewCell
{
    //消息内容视图
    var customView:UIView!
    //消息背景
    var bubbleImage:UIImageView!
    //头像
    var avatarImage:UIImageView!
    //消息数据结构
    var msgItem:MessageItem!
     
    required init(coder aDecoder: NSCoder) {
         
        super.init(coder: aDecoder)
    }
     
    //- (void) setupInternalData
    init(data:MessageItem, reuseIdentifier cellId:String)
    {
        self.msgItem = data
        super.init(style: UITableViewCellStyle.Default, reuseIdentifier:cellId)
        rebuildUserInterface()
    }
     
    func rebuildUserInterface()
    {
         
        self.selectionStyle = UITableViewCellSelectionStyle.None
        if (self.bubbleImage == nil)
        {
            self.bubbleImage = UIImageView()
            self.addSubview(self.bubbleImage)
             
        }
         
        var type =  self.msgItem.mtype
        var width =  self.msgItem.view.frame.size.width
         
        var height =  self.msgItem.view.frame.size.height
         
        var x =  (type == ChatType.Someone) ? 0 : self.frame.size.width - width -
            self.msgItem.insets.left - self.msgItem.insets.right
         
        var y:CGFloat =  0
        //显示用户头像
        if (self.msgItem.logo != "")
        {
             
            var logo =  self.msgItem.logo
             
            self.avatarImage = UIImageView(image:UIImage(named:(logo != "" ? logo : "noAvatar.png")))
             
            self.avatarImage.layer.cornerRadius = 9.0
            self.avatarImage.layer.masksToBounds = true
            self.avatarImage.layer.borderColor = UIColor(white:0.0 ,alpha:0.2).CGColor
            self.avatarImage.layer.borderWidth = 1.0
             
            //别人头像，在左边，我的头像在右边
            var avatarX =  (type == ChatType.Someone) ? 2 : self.frame.size.width - 52
             
            //头像居于消息底部
            var avatarY =  height
            //set the frame correctly
            self.avatarImage.frame = CGRectMake(avatarX, avatarY, 50, 50)
            self.addSubview(self.avatarImage)
             
             
            var delta =  self.frame.size.height - (self.msgItem.insets.top + self.msgItem.insets.bottom
                + self.msgItem.view.frame.size.height)
            if (delta > 0)
            {
                y = delta
            }
            if (type == ChatType.Someone)
            {
                x += 54
            }
            if (type == ChatType.Mine)
            {
                x -= 54
            }
        }
         
        self.customView = self.msgItem.view
        self.customView.frame = CGRectMake(x + self.msgItem.insets.left, y
            + self.msgItem.insets.top, width, height)
         
        self.addSubview(self.customView)
         
        //如果是别人的消息，在左边，如果是我输入的消息，在右边
        if (type == ChatType.Someone)
        {
            self.bubbleImage.image =
                UIImage(named:("yoububble.png"))!.stretchableImageWithLeftCapWidth(21,topCapHeight:14)
             
        }
        else {
            self.bubbleImage.image =
                UIImage(named:"mebubble.png")!.stretchableImageWithLeftCapWidth(15, topCapHeight:14)
        }
        self.bubbleImage.frame = CGRectMake(x, y, width + self.msgItem.insets.left
            + self.msgItem.insets.right, height + self.msgItem.insets.top + self.msgItem.insets.bottom)
    }
}