- (void)postNotificationName:(NSString *)aName object:(id)anObject userInfo:(NSDictionary *)aUserInfo;//发布一个名称为aName的通知，anObject为这个通知的发布者，aUserInfo为额外信息

- (void)addObserver:(id)observer selector:(SEL)aSelector name:(NSString *)aName object:(id)anObject;/**observer：监听器，即谁要接收这个通知aSelector：收到通知后，回调监听器的这个方法，并且把通知对象当做参数传入aName：通知的名称。如果为nil，那么无论通知的名称是什么，监听器都能收到这个通知anObject：通知发布者。如果为anObject和aName都为nil，监听器都收到所有的通知*/

/*通知中心不会保留(retain)监听器对象，在通知中心注册过的对象，必须在该对象释放前取消注册。否则，当相应的通知再次出现时，通知中心仍然会向该监听器发送消息。因为相应的监听器对象已经被释放了，所以可能会导致应用崩溃通知中心提供了相应的方法来取消注册监听器*/- (void)removeObserver:(id)observer;- (void)removeObserver:(id)observer name:(NSString *)aName object:(id)anObject;//一般在监听器销毁之前取消注册（如在监听器中加入下列代码）：- (void)dealloc {    //[super dealloc];  非ARC中需要调用此句    [[NSNotificationCenter defaultCenter] removeObserver:self];}

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChangeFrame:) name:UIKeyboardWillChangeFrameNotification object:nil];

/*** 数据模型* MessageDataModel.m*/@implementation MessageDataModel+(instancetype)messageWithDict:(NSDictionary *)dict{    return [[self alloc] initWithDict:dict];}-(instancetype)initWithDict:(NSDictionary *)dict{    if(self = [super init]){        [self setValuesForKeysWithDictionary:dict];    }    return self;}@end

/*** 位置模型* MessageFrameData.m*/#define MJTextFont [UIFont systemFontOfSize:15]#import "MessageFrameData.h"#import "MessageDataModel.h"@implementation MessageFrameData-(void)setMessage:(MessageDataModel *)message {    _message = message;//    间距    CGFloat padding = 10;//    屏幕的宽度    CGFloat screenW = [UIScreen mainScreen].bounds.size.width;    NSLog(@"==========%f",screenW);//    时间布局    if(!message.hideTime){        CGFloat timeX = 0;        CGFloat timeY = 0;        CGFloat timeW = screenW;        CGFloat timeH = 40;        _timeF = CGRectMake(timeX, timeY, timeW, timeH);    }//    头像布局    CGFloat iconY = CGRectGetMaxY(_timeF)+padding;    CGFloat iconW = 40;    CGFloat iconH = 40;    CGFloat iconX;    if(message.type == MessageTypeOther){//别人发的        iconX = padding;    } else{//自己发的        iconX = screenW - padding -iconW;    }    _iconF = CGRectMake(iconX, iconY, iconW, iconH);//    正文    CGFloat textY = iconY;//    能显示的最大size    CGSize textMaxSize = CGSizeMake(150, MAXFLOAT);//    文本的真实size    CGSize textSize = [self sizeWithText:message.text font:MJTextFont maxSize:textMaxSize];//    最终确定的size；    CGSize textBtnSize = CGSizeMake(textSize.width+ TextPadding*2, textSize.height+ TextPadding*2);    CGFloat textX;    if(message.type == MessageTypeOther){        textX = CGRectGetMaxX(_iconF)+padding;    } else{        textX = iconX - padding -textBtnSize.width;    }    _textF = (CGRect){{textX,textY},textBtnSize};//    _textF = CGRectMake(textX, textY, textSize.width, textSize.height);    CGFloat textMaxY = CGRectGetMaxY(_textF);    CGFloat iconMaxY = CGRectGetMaxY(_iconF);    _cellHeight = MAX(textMaxY, iconMaxY) + padding;}/***  计算文字尺寸**  @param text    需要计算尺寸的文字*  @param font    文字的字体*  @param maxSize 文字的最大尺寸*/- (CGSize)sizeWithText:(NSString *)text font:(UIFont *)font maxSize:(CGSize)maxSize{    NSDictionary *attrs = @{NSFontAttributeName : font};    return [text boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:attrs context:nil].size;}@end

/*** 自定义cell,用于填充数据和设置frame*/#define MJTextFont [UIFont systemFontOfSize:15]#import "QQQViewCellTableViewCell.h"#import "MessageDataModel.h"#import "UIImage+Extension.h"@interface QQQViewCellTableViewCell()//内容@property (nonatomic, weak) UIButton *textView;//发送时间@property (nonatomic, weak) UIImageView *iconView;@property (nonatomic, weak)UILabel *timeView;@end@implementation QQQViewCellTableViewCell/*** 重写*/-(id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {//        先调用父类方法    self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];    if (self){//        子空间的创建和初始化//        时间        UILabel *timeView = [[UILabel alloc] init];        timeView.textAlignment = NSTextAlignmentCenter;        timeView.textColor = [UIColor grayColor];        timeView.font = [UIFont systemFontOfSize:13];        [self.contentView addSubview:timeView];        self.timeView = timeView;//       头像        UIImageView *iconView = [[UIImageView alloc] init];        [self.contentView addSubview:iconView];        self.iconView = iconView;//        正文        UIButton *textView = [[UIButton alloc] init];        textView.titleLabel.numberOfLines = 0;//        textView.backgroundColor = [UIColor grayColor];        textView.titleLabel.font = MJTextFont;        [textView setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];//        设置内边距        textView.contentEdgeInsets = UIEdgeInsetsMake(TextPadding, TextPadding, TextPadding, TextPadding);        [self.contentView addSubview:textView];        self.textView = textView;//        设置cell的背景颜色        self.backgroundColor = [UIColor clearColor];    }    return self;}//这是布局-(void)setModel:(MessageFrameData *)model {    _model = model;    MessageDataModel *message = model.message;//    时间    self.timeView.text = message.time;    self.timeView.frame = model.timeF;//    头像    NSString *icon = (message.type == MessageTypeOther)?@"other":@"me";    self.iconView.image = [UIImage imageNamed:icon];    self.iconView.frame = model.iconF;//    正文    [self.textView setTitle:message.text forState:UIControlStateNormal];    self.textView.frame = model.textF;//    设置正文背景图    if (message.type == MessageTypeMe){        [self.textView setBackgroundImage:[UIImage resizableImage:@"chat_send_nor"] forState:UIControlStateNormal];    } else{        [self.textView setBackgroundImage:[UIImage resizableImage:@"chat_recive_nor"] forState:UIControlStateNormal];    }}+(instancetype)cellWithTableView:(UITableView *)tableView{    static NSString *ID = @"qqmessage";    QQQViewCellTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:ID];    if(cell == nil){        cell = [[QQQViewCellTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:ID];    }    return cell;}@end