不同cell实现qq聊天框效果

** 准备工作: **

• 新建DLmessage模型类文件.
• 新建DLMessageCell类文件,将storyboard中cell的class改为DLMessageCell.设置上面cell的重用标识为messageMe,下面cell的重用标识为messageOther.
• 新建DLMessageViewController类文件,将storyboard中的控制器class改为DLMessageViewControlle.

1.将所需控件布局到storyboard,设置控件的图片等属性,并设置控制器为tableView的数据源和代理.
如下图:

2.通过autoLayout设置每个控件的布局,其中button的宽度属性大于等于 60 小于等于 240 ,这样button里面的titleLabel属性就能跟随内容长度变化,从而也就决定了button的宽度长短.在自定义cell类的awakeFromNib方法中设置button中titleLabel的numberOfLines为零,这样就实现了Button内容的自动换行功能.

- (void)awakeFromNib{
   //设置titleLabel达到button最大宽度时自动换行
    self.messageButton.titleLabel.numberOfLines = 0;
}

3.将控件连线DLMessageCell类扩展中.不同cell可以将相同的属性共用.

4.创建DLmessage模型中的成员属性,使其能够加载并记录plist文件数据.

DLmessage.h文件
#import <UIKit/UIKit.h>

typedef enum {
    DLMessageTypeMe = 0,
    DLMessageTypeOther = 1
} DLMessageType;

@interface DLMessage : NSObject
@property(nonatomic,strong) NSString *text;
@property(nonatomic,strong) NSString *time;
@property(nonatomic,assign) DLMessageType type;
//记录行高,取出cell中高度的最大值来赋值
@property(nonatomic,assign) CGFloat cellHeight;
//记录发送时间是否显示
@property(nonatomic,assign,getter=isHideTime) BOOL hideTime;
//构造方法,方便外界传入plist文件
+ (instancetype)messageWithDict:(NSDictionary *)dict;
@end

DLmessage.m文件
#import "DLMessage.h"

@implementation DLMessage
+ (instancetype)messageWithDict:(NSDictionary *)dict{
    DLMessage *message = [[self alloc] init];
    //KVC
    [message setValuesForKeysWithDictionary:dict];
    return message;
}
@end

5.在DLMessageCell.h文件中新建模型类成员属性,在.m中重写set方法,将数据传给子控件

DLMessageCell.h文件

#import <UIKit/UIKit.h>

@class DLMessage;

@interface DLMessageCell : UITableViewCell

@property(nonatomic,strong) DLMessage *message;
@end

DLMessageCell.m文件

#import "DLMessageViewCell.h"
#import "DLMessage.h"
//define this constant if you want to use Masonry without the 'mas_' prefix
#define MAS_SHORTHAND
//define this constant if you want to enable auto-boxing for default syntax
#define MAS_SHORTHAND_GLOBALS
#import "Masonry.h"

@interface DLMessageCell ()

@property (weak, nonatomic) IBOutlet UILabel *timeLabel;
@property (weak, nonatomic) IBOutlet UIButton *messageButton;
@property (weak, nonatomic) IBOutlet UIImageView *iconView;

@end
@implementation DLMessageCell

- (void)awakeFromNib{
    //设置换行
    self.messageButton.titleLabel.numberOfLines = 0;
}
- (void)setMessage:(DLMessage *)message{
    
    _message = message;
    
    //隐藏时间
    if (message.hideTime) {
        self.timeLabel.hidden = YES;
        [self.timeLabel updateConstraints:^(MASConstraintMaker *make) {
            make.height.equalTo(0);
        }];
    }else{//显示时间
        self.timeLabel.hidden = NO;
        self.timeLabel.text = message.time;
        [self.timeLabel updateConstraints:^(MASConstraintMaker *make) {
            make.height.equalTo(21);
        }];
    }
    //设置控件内容
    [self.messageButton setTitle:self.message.text forState:UIControlStateNormal];
    //强制更新
    [self layoutIfNeeded];
    //修改button的高度
    [self.messageButton updateConstraints:^(MASConstraintMaker *make) {
        CGFloat buttonH = self.messageButton.titleLabel.frame.size.height + 30;
        make.height.equalTo(buttonH);
    }];
    [self layoutIfNeeded];
   //获取button与nameView的最大值,设置最大值为cell的高度
    CGFloat buttonY = CGRectGetMaxY(self.messageButton.frame);
    CGFloat iconViewY = CGRectGetMaxY(self.iconView.frame);
    self.message.cellHeight = MAX(buttonY, iconViewY) + 5;
   }
@end

6.在DLMessageViewController中新建数组,加载模型数据,同时实现tableView的数据源方法,需遵守UITableViewDataSource,UITableViewDelegate协议.

#import "DLMessageViewController.h"
#import "DLMessageCell.h"
#import "DLMessage.h"

@interface DLMessageViewController ()<UITableViewDataSource,UITableViewDelegate>

@property(nonatomic,strong) NSArray *messages;
@property (weak, nonatomic) IBOutlet UITextField *messageFeild;
@property (weak, nonatomic) IBOutlet NSLayoutConstraint *buttomSpacing;

@end

@implementation DLMessageViewController
- (NSArray *)messages{
    if (_messages == nil) {
        NSString *path = [[NSBundle mainBundle] pathForResource:@"messages.plist" ofType:nil];
        NSArray *dictArr = [NSArray arrayWithContentsOfFile:path];
        
        NSMutableArray *messageArrM = [NSMutableArray array];
        DLMessage *lastMessage = nil;
        for (NSDictionary *dict in dictArr) {
            
            DLMessage *message = [DLMessage messageWithDict:dict];
            message.hideTime = [lastMessage.time isEqualToString:message.time];
            [messageArrM addObject:message];
            lastMessage = message;
        }
        _messages = messageArrM;
    }
    return _messages;
}

- (void)viewDidLoad {
    [super viewDidLoad];
}
//返回cell的行数
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
    return self.messages.count;
}
//设置cell的数据
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
    //取出模型的数据
    DLMessage *message = self.messages[indexPath.row];
    /*根据模型中type的值来设置数据(方法1)
    DLMessageCell *cell = [[DLMessageCell alloc] init];
    if (message.type == DLMessageTypeMe) {
        cell = [tableView dequeueReusableCellWithIdentifier:@"messageMe"];
    }else if(message.type == DLMessageTypeOther){
        cell = [tableView dequeueReusableCellWithIdentifier:@"messageOther"];
    }
    cell.message = self.messages[indexPath.row];
    return cell;
     */
    // 根据模型中type的值来设置数据(方法2)
    NSString *ID = (message.type == DLMessageTypeMe)? @"messageMe" : @"messageOther";
    DLMessageCell *cell = [tableView dequeueReusableCellWithIdentifier:ID];
    cell.message = message;
    return cell;
}
//返回cell的估计高度
- (CGFloat)tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath{
    return 200;
}
//返回cell的高度
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{
    DLMessage *message = self.messages[indexPath.row];
    return  message.cellHeight;
}