//返回时间格式
NSCalendar *calendar = [NSCalendar currentCalendar];
//1.获取当前的时间
NSDate *currentDate = [NSDate date];
// 获取年，月，日
NSDateComponents *components = [calendar components:NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay fromDate:currentDate];
NSInteger currentYear = components.year;
NSInteger currentMonth = components.month;
NSInteger currentDay = components.day;
//2.获取消息发送时间
NSDate *msgDate = [NSDate dateWithTimeIntervalSince1970:timestamp/1000.0];
// 获取年，月，日
components = [calendar components:NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay fromDate:msgDate];
CGFloat msgYead = components.year;
CGFloat msgMonth = components.month;
CGFloat msgDay = components.day;
//3.判断:
/*今天：(HH:mm)
*昨天: (昨天 HH:mm)
*昨天以前:（2016-09-06 15:27）
*/
NSDateFormatter *dateFmt = [[NSDateFormatter alloc] init];
if (currentYear == msgYead&& currentMonth == msgMonth&& currentDay == msgDay) {//今天
dateFmt.dateFormat= @"hh:mm";
}else if(currentYear == msgYead&& currentMonth == msgMonth&& currentDay - 1 == msgDay){//昨天
dateFmt.dateFormat= @"昨天 hh:mm";
}else{//昨天以前
dateFmt.dateFormat= @"yyy-MM-dd hh:mm";
}
//最终得到的时间
NSString * dateStr = [dateFmt stringFromDate:msgDate];
UIColor扩展(colorWithHexString)
UIColor+Hex.h
#import <UIKit/UIKit.h>
#define RGBA_COLOR(R, G, B, A) [UIColor colorWithRed:((R) / 255.0f) green:((G) / 255.0f) blue:((B) / 255.0f) alpha:A]
#define RGB_COLOR(R, G, B) [UIColor colorWithRed:((R) / 255.0f) green:((G) / 255.0f) blue:((B) / 255.0f) alpha:1.0f]
@interface UIColor (Hex)
+ (UIColor *)colorWithHexString:(NSString *)color;
//从十六进制字符串获取颜色，
//color:支持@“#123456”、 @“0X123456”、 @“123456”三种格式
+ (UIColor *)colorWithHexString:(NSString *)color alpha:(CGFloat)alpha;
@end
UIColor+Hex.m
#import "UIColor+Hex.h"
@implementation UIColor (Hex)
+ (UIColor *)colorWithHexString:(NSString *)color alpha:(CGFloat)alpha
{
//删除字符串中的空格
NSString *cString = [[color stringByTrimmingCharactersInSet: [NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString];
// String should be 6 or 8 characters
if ([cString length] < 6)
{
return [UIColor clearColor];
}
// strip 0X if it appears
//如果是0x开头的，那么截取字符串，字符串从索引为2的位置开始，一直到末尾
if ([cString hasPrefix:@"0X"])
{
cString = [cString substringFromIndex:2];
}
//如果是#开头的，那么截取字符串，字符串从索引为1的位置开始，一直到末尾
if ([cString hasPrefix:@"#"])
{
cString = [cString substringFromIndex:1];
}
if ([cString length] != 6)
{
return [UIColor clearColor];
}
// Separate into r, g, b substrings
NSRange range;
range.location = 0;
range.length = 2;
//r
NSString *rString = [cString substringWithRange:range];
//g
range.location = 2;
NSString *gString = [cString substringWithRange:range];
//b
range.location = 4;
NSString *bString = [cString substringWithRange:range];
// Scan values
unsigned int r, g, b;
[[NSScanner scannerWithString:rString] scanHexInt:&r];
[[NSScanner scannerWithString:gString] scanHexInt:&g];
[[NSScanner scannerWithString:bString] scanHexInt:&b];
return [UIColor colorWithRed:((float)r / 255.0f) green:((float)g / 255.0f) blue:((float)b / 255.0f) alpha:alpha];
}
//默认alpha值为1
+ (UIColor *)colorWithHexString:(NSString *)color
{
return [self colorWithHexString:color alpha:1.0f];
}
@end
使用方法：
将UIColor+Hex.h和UIColor+Hex.m加入到工程。
调用方式：
[UIColor colorWithHexString:@"#3498c8"];