在xcode中以MM / dd / yyyy格式转换日期？

Question

我有UIDatePicker，我以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..我该怎么办？< / p>

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2012-10-30，但我想要10/30/2012。

Answer 1

请参阅每行的说明或介绍

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);

Answer 2

Answer 3

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

Answer 4

看看它是如何结束的：

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);

Answer 5

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

Answer 6

原来接受的答案会做一些额外的事情：

1）它分配两个不需要的NSDateFormatter实例。 NSDateFormatter的创建成本很高。

2）最好在完成日期格式化时明确发布日期格式化程序而不是使用自动释放的延迟发布。

//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];

Answer 7

- (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;
}

享受

Answer 8

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);

Answer 9

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