Will的部落格

此範例為一個日期選擇的應用，

點擊button後，觸發datePciker並顯示於label上，

將UIDatePicker調整到使用者的生日，

計算年齡後並印在Label。

#import "ViewController.h"

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIDatePicker *myDatePicker;
@property (weak, nonatomic) IBOutlet UILabel *dateLabel;
@property (weak, nonatomic) IBOutlet UILabel *ageLabel;
- (IBAction)toEnter:(id)sender;
- (IBAction)datePickerChanged:(id)sender;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (IBAction)toEnter:(id)sender {
    
    if( _myDatePicker.hidden == YES){
        [_myDatePicker setHidden:NO];
    }else{
        [_myDatePicker setHidden:YES];
    }
}

- (IBAction)datePickerChanged:(id)sender {
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
    [dateFormatter setDateFormat:@"YYYY/MM/dd"];
    NSString *dateString = [dateFormatter stringFromDate:[_myDatePicker date]];
    _dateLabel.text = dateString;
    
    NSDate *now =[NSDate date];
    NSDateComponents *ageComponents = [[NSCalendar currentCalendar]
                                       components:NSCalendarUnitYear fromDate:[_myDatePicker date] toDate:now options:0];
    
    NSInteger age = [ageComponents year];
    _ageLabel.text = [NSString stringWithFormat:@"%ld", (long)age];
}

@end