#importvoid other();void string2date();int main(int argc, const char * argv[]) { @autoreleasepool { other(); string2date(); } return 0;}void other(){ // 获得NSCalendar NSCalendar *calendar = nil; if ([NSCalendar respondsToSelector:@selector(calendarWithIdentifier:)]) { calendar = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian]; } else { calendar = [NSCalendar currentCalendar]; } NSDateFormatter *fmt = [[NSDateFormatter alloc] init]; fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss"; NSLog(@"%zd", [calendar isDateInToday:[fmt dateFromString:@"2015-11-10 01:09:56"]]); }void dateCompare3(){ NSDateFormatter *fmt = [[NSDateFormatter alloc] init]; fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss"; // 时间字符串 NSString *createdAtString = @"2015-11-01 09:10:05"; NSDate *createdAtDate = [fmt dateFromString:createdAtString]; // 其他时间 NSString *otherString = @"2015-10-31 08:56:45"; NSDate *otherDate = [fmt dateFromString:otherString]; // 获得NSCalendar NSCalendar *calendar = nil; if ([NSCalendar respondsToSelector:@selector(calendarWithIdentifier:)]) { calendar = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian]; } else { calendar = [NSCalendar currentCalendar]; } // 获得日期之间的间隔 NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond; NSDateComponents *cmps = [calendar components:unit fromDate:createdAtDate toDate:otherDate options:0]; NSLog(@"%@", cmps);}void dateCompare2(){ // 时间字符串 NSString *createdAtString = @"2015-11-20 09:10:05"; NSDateFormatter *fmt = [[NSDateFormatter alloc] init]; fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss"; NSDate *createdAtDate = [fmt dateFromString:createdAtString]; // 手机当前时间 // NSDate *nowDate = [NSDate date]; // 获得createdAtDate和nowDate的时间间隔(间隔多少秒) // NSTimeInterval interval = [nowDate timeIntervalSinceDate:createdAtDate]; NSTimeInterval interval = [createdAtDate timeIntervalSinceNow]; NSLog(@"%f", interval);}void dateCompare(){ // 时间字符串 NSString *createdAtString = @"2015-11-20 11:10:05"; NSDateFormatter *fmt = [[NSDateFormatter alloc] init]; fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss"; NSDate *createdAtDate = [fmt dateFromString:createdAtString]; // 手机当前时间 NSDate *nowDate = [NSDate date]; /** NSComparisonResult的取值 NSOrderedAscending = -1L, // 升序, 越往右边越大 NSOrderedSame, // 相等 NSOrderedDescending // 降序, 越往右边越小 */ // 获得比较结果(谁大谁小) NSComparisonResult result = [nowDate compare:createdAtDate]; if (result == NSOrderedAscending) { // 升序, 越往右边越大 NSLog(@"createdAtDate > nowDate"); } else if (result == NSOrderedDescending) { // 降序, 越往右边越小 NSLog(@"createdAtDate < nowDate"); } else { NSLog(@"createdAtDate == nowDate"); }}/** * 日期元素 : 年月日时分秒 */void getComponentsOfDate3(){ // 时间字符串 NSString *string = @"2015-11-20 09:10:05"; // 日期格式化类 NSDateFormatter *fmt = [[NSDateFormatter alloc] init]; // 设置日期格式(为了转换成功) fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss"; // NSString * -> NSDate * NSDate *date = [fmt dateFromString:string]; // 利用NSCalendar处理日期 NSCalendar *calendar = [NSCalendar currentCalendar]; NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond; NSDateComponents *cmps = [calendar components:unit fromDate:date]; // NSLog(@"%zd %zd %zd", cmps.year, cmps.month, cmps.day); NSLog(@"%@", cmps);}/** * 日期元素 : 年月日时分秒 */void getComponentsOfDate2(){ // 时间字符串 NSString *string = @"2015-11-20 09:10:05"; // 日期格式化类 NSDateFormatter *fmt = [[NSDateFormatter alloc] init]; // 设置日期格式(为了转换成功) fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss"; // NSString * -> NSDate * NSDate *date = [fmt dateFromString:string]; // 利用NSCalendar处理日期 NSCalendar *calendar = [NSCalendar currentCalendar]; NSInteger month = [calendar component:NSCalendarUnitMonth fromDate:date]; NSInteger hour = [calendar component:NSCalendarUnitHour fromDate:date]; NSInteger minute = [calendar component:NSCalendarUnitMinute fromDate:date]; NSLog(@"%zd %zd %zd", month, hour, minute);}/** * 日期元素 : 年月日时分秒 */void getComponentsOfDate(){ // 时间字符串 NSString *string = @"2015-11-20 09:10:05"; NSString *month = [string substringWithRange:NSMakeRange(5, 2)]; NSLog(@"%@", month);}void date2string(){ NSDate *date = [NSDate date]; NSDateFormatter *fmt = [[NSDateFormatter alloc] init]; fmt.dateFormat = @"yyyy年MM月dd号 HH:mm:ss"; NSString *string = [fmt stringFromDate:date]; NSLog(@"----%@+++++", string); }void string2date4(){ // 时间戳 : 从1970年1月1号 00:00:00开始走过的毫秒数 // 时间字符串 - 时间戳 NSString *string = @"1745645645645"; NSTimeInterval second = string.longLongValue / 1000.0; // 时间戳 -> NSDate * NSDate *date = [NSDate dateWithTimeIntervalSince1970:second]; NSLog(@"%@", date);}void string2date3(){ // 时间字符串 NSString *string = @"Tue May 31 17:46:55 +0800 2011"; // 日期格式化类 NSDateFormatter *fmt = [[NSDateFormatter alloc] init]; fmt.dateFormat = @"EEE MMM dd HH:mm:ss Z yyyy"; // fmt.dateFormat = @"EEE MMM dd HH:mm:ss ZZZZ yyyy"; // 设置语言区域(因为这种时间是欧美常用时间) fmt.locale = [[NSLocale alloc] initWithLocaleIdentifier:@"en_US"]; NSLog(@"%@", [fmt dateFromString:string]);}void string2date2(){ // 时间字符串 NSString *string = @"11月-20号/2015年 09-10:05秒"; // 日期格式化类 NSDateFormatter *fmt = [[NSDateFormatter alloc] init]; fmt.dateFormat = @"MM月-dd号/yyyy年 HH-mm:ss秒"; NSLog(@"%@", [fmt dateFromString:string]);}void string2date(){ // 时间字符串 NSString *string = @"2015-11-20 09:33:22"; // 日期格式化类 NSDateFormatter *fmt = [[NSDateFormatter alloc] init]; // 设置日期格式(为了转换成功) fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss"; // NSString * -> NSDate * NSDate *date = [fmt dateFromString:string]; NSString *newStr = [fmt stringFromDate:date]; NSLog(@"%@", date); NSLog(@"%@", newStr); }
总结：
## NSDateFormatter的作用
- NSString \* -> NSDate *
```obj
- (nullable NSDate *)dateFromString:(NSString *)string;
```
- NSDate \* -> NSString *
```objc
- (NSString *)stringFromDate:(NSDate *)date;
```
## 常见的日期格式
- http://www.cnblogs.com/mailingfeng/archive/2011/07/28/2120422.html
## NSString \* -> NSDate *
- 2015-11-20 09:10:05
```objc
// 时间字符串
NSString *string = @"2015-11-20 09:10:05";
// 日期格式化类
NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
// 设置日期格式(为了转换成功)
fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss";
// NSString * -> NSDate *
NSDate *date = [fmt dateFromString:string];
NSLog(@"%@", date);
```
- 11月-20号/2015年 09-10:05秒
```objc
// 时间字符串
NSString *string = @"11月-20号/2015年 09-10:05秒";
// 日期格式化类
NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
fmt.dateFormat = @"MM月-dd号/yyyy年 HH-mm:ss秒";
NSLog(@"%@", [fmt dateFromString:string]);
```
- Tue May 31 17:46:55 +0800 2011
```objc
// 时间字符串
NSString *string = @"Tue May 31 17:46:55 +0800 2011";
// 日期格式化类
NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
fmt.dateFormat = @"EEE MMM dd HH:mm:ss Z yyyy";
// fmt.dateFormat = @"EEE MMM dd HH:mm:ss ZZZZ yyyy";
// 设置语言区域(因为这种时间是欧美常用时间)
fmt.locale = [[NSLocale alloc] initWithLocaleIdentifier:@"en_US"];
NSLog(@"%@", [fmt dateFromString:string]);
```
- 1745645645645
```objc
// 时间戳 : 从1970年1月1号 00:00:00开始走过的毫秒数
// 时间字符串 - 时间戳
NSString *string = @"1745645645645";
NSTimeInterval second = string.longLongValue / 1000.0;
// 时间戳 -> NSDate *
NSDate *date = [NSDate dateWithTimeIntervalSince1970:second];
NSLog(@"%@", date);
```
## NSCalendar的注意点
```objc
#define iOS(version) ([UIDevice currentDevice].systemVersion.doubleValue >= (version))
NSCalendar *calendar = nil;
if ([UIDevice currentDevice].systemVersion.doubleValue >= 8.0) {
calendar = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian];
} else {
calendar = [NSCalendar currentCalendar];
}
NSCalendar *calendar = nil;
if ([NSCalendar respondsToSelector:@selector(calendarWithIdentifier:)]) {
calendar = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian];
} else {
calendar = [NSCalendar currentCalendar];
}
```
## NSDate \* -> NSString *
```objc
NSDate *date = [NSDate date];
NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
fmt.dateFormat = @"yyyy年MM月dd号 HH:mm:ss";
NSString *string = [fmt stringFromDate:date];
```
## 获得日期元素
```objc
NSString *string = @"2015-11-20 09:10:05";
NSString *month = [string substringWithRange:NSMakeRange(5, 2)];
NSLog(@"%@", month);
```
```objc
// 时间字符串
NSString *string = @"2015-11-20 09:10:05";
// 日期格式化类
NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
// 设置日期格式(为了转换成功)
fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss";
// NSString * -> NSDate *
NSDate *date = [fmt dateFromString:string];
// 利用NSCalendar处理日期
NSCalendar *calendar = [NSCalendar currentCalendar];
NSInteger month = [calendar component:NSCalendarUnitMonth fromDate:date];
NSInteger hour = [calendar component:NSCalendarUnitHour fromDate:date];
NSInteger minute = [calendar component:NSCalendarUnitMinute fromDate:date];
NSLog(@"%zd %zd %zd", month, hour, minute);
```
```objc
// 时间字符串
NSString *string = @"2015-11-20 09:10:05";
// 日期格式化类
NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
// 设置日期格式(为了转换成功)
fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss";
// NSString * -> NSDate *
NSDate *date = [fmt dateFromString:string];
// 利用NSCalendar处理日期
NSCalendar *calendar = [NSCalendar currentCalendar];
NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;
NSDateComponents *cmps = [calendar components:unit fromDate:date];
// NSLog(@"%zd %zd %zd", cmps.year, cmps.month, cmps.day);
NSLog(@"%@", cmps);
```
## 日期比较
```objc
// 时间字符串
NSString *createdAtString = @"2015-11-20 11:10:05";
NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss";
NSDate *createdAtDate = [fmt dateFromString:createdAtString];
// 手机当前时间
NSDate *nowDate = [NSDate date];
/**
NSComparisonResult的取值
NSOrderedAscending = -1L, // 升序, 越往右边越大
NSOrderedSame, // 相等
NSOrderedDescending // 降序, 越往右边越小
*/
// 获得比较结果(谁大谁小)
NSComparisonResult result = [nowDate compare:createdAtDate];
if (result == NSOrderedAscending) { // 升序, 越往右边越大
NSLog(@"createdAtDate > nowDate");
} else if (result == NSOrderedDescending) { // 降序, 越往右边越小
NSLog(@"createdAtDate < nowDate");
} else {
NSLog(@"createdAtDate == nowDate");
}
```
```objc
// 时间字符串
NSString *createdAtString = @"2015-11-20 09:10:05";
NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss";
NSDate *createdAtDate = [fmt dateFromString:createdAtString];
// 手机当前时间
// NSDate *nowDate = [NSDate date];
// 获得createdAtDate和nowDate的时间间隔(间隔多少秒)
// NSTimeInterval interval = [nowDate timeIntervalSinceDate:createdAtDate];
NSTimeInterval interval = [createdAtDate timeIntervalSinceNow];
NSLog(@"%f", interval);
```
```objc
NSDateFormatter *fmt = [[NSDateFormatter alloc] init];
fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss";
// 时间字符串
NSString *createdAtString = @"2015-11-01 09:10:05";
NSDate *createdAtDate = [fmt dateFromString:createdAtString];
// 其他时间
NSString *otherString = @"2015-10-31 08:56:45";
NSDate *otherDate = [fmt dateFromString:otherString];
// 获得NSCalendar
NSCalendar *calendar = nil;
if ([NSCalendar respondsToSelector:@selector(calendarWithIdentifier:)]) {
calendar = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian];
} else {
#import//typedef enum {// /** 图片 */// XMGTopicTypePicture = 10,// /** 段子 */// XMGTopicTypeWord = 29,// /** 声音 */// XMGTopicTypeVoice = 31,// /** 视频 */// XMGTopicTypeVideo = 41,//} XMGTopicType;typedef NS_ENUM(NSUInteger, XMGTopicType) { /** 图片 */ XMGTopicTypePicture = 10, /** 段子 */ XMGTopicTypeWord = 29, /** 声音 */ XMGTopicTypeVoice = 31, /** 视频 */ XMGTopicTypeVideo = 41};@class XMGComment;@interface XMGTopic : NSObject/** 用户的名字 */@property (nonatomic, copy) NSString *name;/** 用户的头像 */@property (nonatomic, copy) NSString *profile_image;/** 帖子的文字内容 */@property (nonatomic, copy) NSString *text;/** 帖子审核通过的时间 */@property (nonatomic, copy) NSString *created_at;/** 顶数量 */@property (nonatomic, assign) NSInteger ding;/** 踩数量 */@property (nonatomic, assign) NSInteger cai;/** 转发\分享数量 */@property (nonatomic, assign) NSInteger repost;/** 评论数量 */@property (nonatomic, assign) NSInteger comment;/** 最热评论 */@property (nonatomic, strong) XMGComment *top_cmt;/** 帖子类型 */@property (nonatomic, assign) XMGTopicType type;@end
#import "XMGTopic.h"@implementation XMGTopic#pragma mark - 其他static NSDateFormatter *fmt_;static NSCalendar *calendar_;/** * 在第一次使用XMGTopic类时调用1次 */+ (void)initialize{ fmt_ = [[NSDateFormatter alloc] init]; calendar_ = [NSCalendar calendar];}- (NSString *)created_at{ // 获得发帖日期 fmt_.dateFormat = @"yyyy-MM-dd HH:mm:ss"; NSDate *createdAtDate = [fmt_ dateFromString:_created_at]; if (createdAtDate.isThisYear) { // 今年 if (createdAtDate.isToday) { // 今天 // 手机当前时间 NSDate *nowDate = [NSDate date]; NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond; NSDateComponents *cmps = [calendar_ components:unit fromDate:createdAtDate toDate:nowDate options:0]; if (cmps.hour >= 1) { // 时间间隔 >= 1小时 return [NSString stringWithFormat:@"%zd小时前", cmps.hour]; } else if (cmps.minute >= 1) { // 1小时 > 时间间隔 >= 1分钟 return [NSString stringWithFormat:@"%zd分钟前", cmps.minute]; } else { // 1分钟 > 分钟 return @"刚刚"; } } else if (createdAtDate.isYesterday) { // 昨天 fmt_.dateFormat = @"昨天 HH:mm:ss"; return [fmt_ stringFromDate:createdAtDate]; } else { // 其他 fmt_.dateFormat = @"MM-dd HH:mm:ss"; return [fmt_ stringFromDate:createdAtDate]; } } else { // 非今年 return _created_at; }}@end
calendar = [NSCalendar currentCalendar];
}
// 获得日期之间的间隔
NSCalendarUnit unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;
NSDateComponents *cmps = [calendar components:unit fromDate:createdAtDate toDate:otherDate options:0];
NSLog(@"%@", cmps);
```
例子：