iOS类似微信聊天界面时间转换

#import <Foundation/Foundation.h>
//聊天时间转换工具类
@interface GetChatTime : NSObject

/**
 聊天时间转换器，非常好用

 @param TimeInterval 时间，传入毫秒，里面自动转为秒（double类型）
 @param needTime 是否显示昨天今天后面的时间
 @return 时间字符串
 */
+(NSString *)getMessageDateStringFromTimeInterval:(NSTimeInterval)TimeInterval andNeedTime:(BOOL)needTime;
@end

#import "GetChatTime.h"

@implementation GetChatTime

/**
 聊天时间转换器，非常好用（调用此方法）
 
 @param TimeInterval 时间，传入毫秒，里面自动转为秒（double类型）
 @param needTime 是否显示昨天今天后面的时间
 @return 时间字符串
 */
+(NSString *)getMessageDateStringFromTimeInterval:(NSTimeInterval)TimeInterval andNeedTime:(BOOL)needTime
{
    //毫秒转秒（必须，否则死循环）
    TimeInterval= TimeInterval/1000;
    NSDate *date = [NSDate dateWithTimeIntervalSince1970:TimeInterval];
    return [GetChatTime getMessageDateString:date andNeedTime:needTime];
}

+ (NSString*)getMessageDateString:(NSDate*)messageDate andNeedTime:(BOOL)needTime
{
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setLocale:[NSLocale systemLocale]];
    [formatter setTimeZone:[NSTimeZone systemTimeZone]];
    [formatter setDateFormat:@"YYYY/MM/dd HH:mm"];
    
    NSCalendar *cal = [NSCalendar currentCalendar];
    NSDateComponents *components = [cal components:NSEraCalendarUnit|NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit|NSWeekdayCalendarUnit fromDate:messageDate];
    NSDate *msgDate = [cal dateFromComponents:components];
    
    NSString*weekday = [GetChatTime getWeekdayWithNumber:components.weekday];
    
    components = [cal components:NSEraCalendarUnit|NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit|NSWeekdayCalendarUnit fromDate:[NSDate date]];
    NSDate *today = [cal dateFromComponents:components];
    
    if([today isEqualToDate:msgDate]){
        if (needTime) {
            [formatter setDateFormat:@"今天 HH:mm"];
        }
        else{
            [formatter setDateFormat:@"今天"];
        }
        return [formatter stringFromDate:messageDate];
    }
    
    components.day -= 1;
    NSDate *yestoday = [cal dateFromComponents:components];
    if([yestoday isEqualToDate:msgDate]){
        if (needTime) {
            [formatter setDateFormat:@"昨天 HH:mm"];
        }
        else{
            [formatter setDateFormat:@"昨天"];
        }
        return [formatter stringFromDate:messageDate];
    }
#pragma mark ========= 修改代码为 i <= 5，修改前 i <= 6=============
    for (int i = 1; i <= 5; i++) {
        components.day -= 1;
        NSDate *nowdate = [cal dateFromComponents:components];
        if([nowdate isEqualToDate:msgDate]){
            if (needTime) {
                [formatter setDateFormat:[NSString stringWithFormat:@"%@ HH:mm",weekday]];
            }
            else{
                [formatter setDateFormat:[NSString stringWithFormat:@"%@",weekday]];
            }
            return [formatter stringFromDate:messageDate];
        }
    }
    
    while (1) {
        components.day -= 1;
        NSDate *nowdate = [cal dateFromComponents:components];
        if ([nowdate isEqualToDate:msgDate]) {
            if (!needTime) {
                [formatter setDateFormat:@"YYYY/MM/dd"];
            }
            return [formatter stringFromDate:messageDate];
            break;
        }
    }
    
}

//1代表星期日、如此类推
+(NSString *)getWeekdayWithNumber:(int)number
{
    switch (number) {
        case 1:
            return @"星期日";
            break;
        case 2:
            return @"星期一";
            break;
        case 3:
            return @"星期二";
            break;
        case 4:
            return @"星期三";
            break;
        case 5:
            return @"星期四";
            break;
        case 6:
            return @"星期五";
            break;
        case 7:
            return @"星期六";
            break;
        default:
            return @"";
            break;
    }
}
@end

下面这个大家不用看，仅供参考，类似微信聊天界面每隔5分钟显示一次时间

//计算每条消息是否显示时间
//dataArray:UITableView的数据源
-(void)computeVisibleTimeAndRefreshTable:(NSString *)type{
    RCmessageContentModel *modeTime;
    long long  lastVisibleTime = 0;
    for (int i=0; i<self.dataSouce.count; i++) {
        modeTime = self.dataSouce[i];
        if (i==0) {
            //一定显示时间
            modeTime.isTimeVisible=true;
            //最后的时间
            lastVisibleTime = modeTime.sentTime;
            
        }else{
            
            //计算时间差，毫秒（5分钟）
            long long timeSpan = modeTime.sentTime - lastVisibleTime;
            if (timeSpan>=5*60*1000){
                //一定显示时间
                modeTime.isTimeVisible=true;
                //最后的时间
                lastVisibleTime = modeTime.sentTime;
            }else{
                //不展示时间
                modeTime.isTimeVisible=false;
            }
        }
        //时间设置完成后数组替换
        self.dataSouce[i]=modeTime;
    }
    //刷新表格，判断完时间后的刷新
    dispatch_async(dispatch_get_main_queue(), ^{
        [self.tableView reloadData];
        if ([type isEqual:@"历史消息"]) {
            //tableview滚动到最底部
            [UIView scrollTableToFoot:self.tableView Animated:NO];
        }else{
            //tableview滚动到最底部
            [UIView scrollTableToFoot:self.tableView Animated:YES];
            
        }
    });
    
}