Objective c 是否在xcode中将日期转换为MM/dd/yyyy格式？

我有一个

UIDatePicker

，我正在以

yyyy-MM-dd

格式从中获取所选日期。现在我想将其转换为

MM/dd/yyyy

格式。我该怎么做

NSDateFormatter *df=[[[NSDateFormatter alloc]init] autorelease];
df.dateFormat = @"yyyy-MM-dd";
NSArray *temp=[[NSString stringWithFormat:@"%@",[df stringFromDate:DatePicker.date]] componentsSeparatedByString:@""];

[dateString2 release];
dateString2=nil;
dateString2= [[NSString alloc]initWithString:[temp objectAtIndex:0]];
NSLog(@"%@",dateString2);

---

我得到的是2012-10-30，但我想要的是2012年10月30日。

df.dateFormat=@“MM/dd/yyyy”

每行见说明或介绍

NSString *str = @"2012-10-30"; /// here this is your date with format yyyy-MM-dd

NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init] autorelease]; // here we create NSDateFormatter object for change the Format of date..
[dateFormatter setDateFormat:@"yyyy-MM-dd"]; //// here set format of date which is in your output date (means above str with format)

NSDate *date = [dateFormatter dateFromString: str]; // here you can fetch date from string with define format

dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setDateFormat:@"dd/MM/yyyy"];// here set format which you want...

NSString *convertedString = [dateFormatter stringFromDate:date]; //here convert date in NSString
NSLog(@"Converted String : %@",convertedString);

---

看看结果如何：

NSDateFormatter* df = [[[NSDateFormatter alloc]init] autorelease];
df.dateFormat = @"MM/dd/yyyy";
NSString* dateString = [df stringFromDate:datePicker.date];  // Don't use leading caps on variables
NSLog(@"%@", dateString);

---

最初被接受的答案做了一些额外的事情：

1） 它分配两个非必需的NSDateFormatter实例。NSDateFormatter的创建成本很高

2） 最好在使用完日期格式化程序后显式发布，而不是使用autorelease延迟发布

//get datepicker date (NSDate *)
NSDate *datePickerDate = [myDatePicker date];

//create a date formatter
NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; 

//set its format as the required output format
[formatter setDateFormat:@"MM/dd/yyyy"];

//get the output date as string
NSString *outputDateString = [formatter stringFromDate:datePickerDate];

//release formatter
[formatter release];

---

享受

我使用带有选项NSISO8601DateFormatWithDashSeparatorInDate的代码：

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
NSString * stringformat = [NSDateFormatter dateFormatFromTemplate:@"MMddy" options:NSISO8601DateFormatWithDashSeparatorInDate locale:[NSLocale systemLocale]];
[dateFormatter setDateFormat:stringformat];

NSDate *d = [NSDate date]; // or set your date
NSLog(@"date in format %@",  [dateFormatter stringFromDate:d]); // date in format 2018-06-20

---

这与Xcode无关，而是与Cocoa Touch框架有关。附录F是你的朋友吗，更改日期格式化程序格式？@HotLicks嘿，伙计，我只是把这个答案和说明一起发布，这样任何人都可以很容易地理解整个流程，所以我把这个流程放在这里…：）@热舔是因为原始问题源于yyyy-MM-dd。此答案涵盖了这一点。所以，如果你投了反对票，那就请你。解释原因。@Da_吸烟——最初的问题来自一个来自UIDatePicker的NSDate。

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];    
[formatter setDateFormat:@"MM/dd/yyyy"];    

//get datepicker date (NSDate *)
NSDate *datePickerDate = [myDatePicker date];

//create a date formatter
NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; 

//set its format as the required output format
[formatter setDateFormat:@"MM/dd/yyyy"];

//get the output date as string
NSString *outputDateString = [formatter stringFromDate:datePickerDate];

//release formatter
[formatter release];

- (void)showTime {
   NSDate *now = [NSDate date];
   NSDateFormatter *dateFormatter = [NSDateFormatter new];
   [dateFormatter setDateFormat:@"HH:mm:ss"];
   // you label
   _time.text = [dateFormatter stringFromDate:now]; 
}

- (void)showDate {
   NSDate *now = [NSDate date];
   NSDateFormatter *dateFormatter = [NSDateFormatter new];
   [dateFormatter setDateFormat:@"MM/dd/yyyy"];
   // you label
   _date.text = [dateFormatter stringFromDate:now];
}

- (void)viewDidLoad {
   [super viewDidLoad];
    self.showTime;
    self.showDate;
}

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
NSString * stringformat = [NSDateFormatter dateFormatFromTemplate:@"MMddy" options:NSISO8601DateFormatWithDashSeparatorInDate locale:[NSLocale systemLocale]];
[dateFormatter setDateFormat:stringformat];

NSDate *d = [NSDate date]; // or set your date
NSLog(@"date in format %@",  [dateFormatter stringFromDate:d]); // date in format 2018-06-20