** 準備工作: **

• 新建DLmessage模型類文件.
• 新建DLMessageCell類文件,將storyboard中cell的class改為DLMessageCell.設置上面cell的重用標識為messageMe,下面cell的重用標識為messageOther.
• 新建DLMessageViewController類文件,將storyboard中的控制器class改為DLMessageViewControlle.

1.將所需控件布局到storyboard,設置控件的圖片等屬性,并設置控制器為tableView的數(shù)據(jù)源和代理.
如下圖:

設置控件

設置數(shù)據(jù)源和代理

2.通過autoLayout設置每個控件的布局,其中button的寬度屬性大于等于 60 小于等于 240 ,這樣button里面的titleLabel屬性就能跟隨內(nèi)容長度變化,從而也就決定了button的寬度長短.在自定義cell類的awakeFromNib方法中設置button中titleLabel的numberOfLines為零,這樣就實現(xiàn)了Button內(nèi)容的自動換行功能.

- (void)awakeFromNib{
   //設置titleLabel達到button最大寬度時自動換行
    self.messageButton.titleLabel.numberOfLines = 0;
}

3.將控件連線DLMessageCell類擴展中.不同cell可以將相同的屬性共用.

連線控件

4.創(chuàng)建DLmessage模型中的成員屬性,使其能夠加載并記錄plist文件數(shù)據(jù).

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;
//記錄行高,取出cell中高度的最大值來賦值
@property(nonatomic,assign) CGFloat cellHeight;
//記錄發(fā)送時間是否顯示
@property(nonatomic,assign,getter=isHideTime) BOOL hideTime;
//構造方法,方便外界傳入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文件中新建模型類成員屬性,在.m中重寫set方法,將數(shù)據(jù)傳給子控件

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{
    //設置換行
    self.messageButton.titleLabel.numberOfLines = 0;
}
- (void)setMessage:(DLMessage *)message{
    
    _message = message;
    
    //隱藏時間
    if (message.hideTime) {
        self.timeLabel.hidden = YES;
        [self.timeLabel updateConstraints:^(MASConstraintMaker *make) {
            make.height.equalTo(0);
        }];
    }else{//顯示時間
        self.timeLabel.hidden = NO;
        self.timeLabel.text = message.time;
        [self.timeLabel updateConstraints:^(MASConstraintMaker *make) {
            make.height.equalTo(21);
        }];
    }
    //設置控件內(nèi)容
    [self.messageButton setTitle:self.message.text forState:UIControlStateNormal];
    //強制更新
    [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];
   //獲取button與nameView的最大值,設置最大值為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中新建數(shù)組,加載模型數(shù)據(jù),同時實現(xiàn)tableView的數(shù)據(jù)源方法,需遵守UITableViewDataSource,UITableViewDelegate協(xié)議.

#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的行數(shù)
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
    return self.messages.count;
}
//設置cell的數(shù)據(jù)
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
    //取出模型的數(shù)據(jù)
    DLMessage *message = self.messages[indexPath.row];
    /*根據(jù)模型中type的值來設置數(shù)據(jù)(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;
     */
    // 根據(jù)模型中type的值來設置數(shù)據(jù)(方法2)
    NSString *ID = (message.type == DLMessageTypeMe)? @"messageMe" : @"messageOther";
    DLMessageCell *cell = [tableView dequeueReusableCellWithIdentifier:ID];
    cell.message = message;
    return cell;
}
//返回cell的估計高度
- (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;
}