Creating a Custom UIDatePicker for Minute and Second Selection

In this article, we will explore how to create a custom UIDatePicker that allows users to select minutes and seconds separately. This can be useful in various applications where precise time selection is required.

Introduction

The UIDatePicker control is a part of the UIKit framework and provides a simple way for users to select dates. However, by default, it only displays hours and minutes as separate units. If you need more precision in your application, such as in a medical or scientific context where exact times are crucial, you may want to consider creating a custom UIDatePicker.

Understanding the Default UIDatepicker

Let’s take a closer look at how the default UIDatePicker works.

{< highlight objective-c >}
- (instancetype)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        // Create a date range with a minimum of 00:00:00 and a maximum of 23:59:59
        NSCalendar *calendar = [NSCalendar currentCalendar];
        NSDateComponents *dateComponents = [NSDateComponents new];
        dateComponents.hour = 0;
        dateComponents.minute = 0;
        dateComponents.second = 0;
        
        // Create an array of dates from the minimum to the maximum
        NSArray *dates = [calendar daysFromDate:dateComponents toDate:[NSDate date] options:0];
        for (NSCalendarUnit unit in @[@"year", @"month", @"day"]) {
            NSDateComponents *dateComponent = [calendar components:(unit | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond) fromDate:dateComponents];
            [dates addObject:[calendar dateFromComponents:dateComponent]];
        }
        
        // Set the selected date to 00:00:00
        self.datePickerDate = dates.firstObject;
    }
    return self;
}
{< /highlight >}

Creating a Custom UIDatepicker

As suggested in the Stack Overflow post, you can create a custom UIDatepicker by subclassing it and overriding its behavior.

{< highlight objective-c >}
@interface MyCustomDatepicker : UIPickerView

@property (nonatomic) double minuteValue;
@property (nonatomic) double secondValue;

@end

Implementing the Custom UIDatepicker

Now that we have our custom UIDatepicker class, let’s implement its behavior.

{< highlight objective-c >}
@implementation MyCustomDatepicker

- (instancetype)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        // Initialize the minute and second values to 0
        _minuteValue = 0;
        _secondValue = 0;
        
        // Create an array of possible minute values
        NSArray *minuteValues = @[@0, @1, @2, @3, @4, @5, @6, @7, @8, @9];
        // Create an array of possible second values
        NSArray *secondValues = @[@0, @30, @60, @90];
        
        // Add the minute and second values to our UIPickerView
        [self addItemsToPickerView:minuteValues];
        [self addItemsToPickerView:secondValues];
    }
    return self;
}

- (void"valueChanged:(UIDatePicker *)picker" {
    // Update our custom values when a new date is selected
    double hour = [picker selectedDate].hour;
    int minuteIndex = [[picker selectedDate] minute];
    double second = ([picker selectedDate] minute) % 60.0;
    
    if (minuteIndex < [minuteValues count]) {
        _minuteValue = minuteIndex / 10.0;
    } else {
        // If the minute value is greater than or equal to 1, set it to 0
        _minuteValue = 0;
    }
    
    if (second < [secondValues count]) {
        _secondValue = second / 10.0;
    } else {
        // If the second value is greater than or equal to 3, set it to 0
        _secondValue = 0;
    }
}

@end

Using Our Custom UIDatepicker

Now that we have our custom UIDatepicker class implemented, let’s see how we can use it in a view controller.

{< highlight objective-c >}
@interface MyViewController : UIViewController

@property (nonatomic) MyCustomDatepicker *customDatepicker;

@end

Implementing the ViewController

Now that we have our custom UIDatepicker class, let’s implement its usage in our view controller.

{< highlight objective-c >}
@implementation MyViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    // Create an instance of our custom datepicker
    _customDatepicker = [[MyCustomDatepicker alloc] initWithFrame:CGRectMake(0, 0, 200, 300)];
    
    // Add the custom datepicker to our view controller's view
    [_customDatepicker addTarget:self action:@selector(valueChanged:) forControlEvents:UIControlEventValueChanged];
    [self.view addSubview:_customDatepicker];
}

- (void)valueChanged:(UIDatePicker *)picker {
    // Update our custom values when a new date is selected
    double hour = [picker selectedDate].hour;
    int minuteIndex = [[picker selectedDate] minute];
    double second = ([picker selectedDate] minute) % 60.0;
    
    if (minuteIndex < [minuteValues count]) {
        self.minuteValue = minuteIndex / 10.0;
    } else {
        // If the minute value is greater than or equal to 1, set it to 0
        self.minuteValue = 0;
    }
    
    if (second < [secondValues count]) {
        self.secondValue = second / 10.0;
    } else {
        // If the second value is greater than or equal to 3, set it to 0
        self.secondValue = 0;
    }
}

@end

Conclusion

In this article, we have explored how to create a custom UIDatepicker that allows users to select minutes and seconds separately. By subclassing the default UIDatepicker, we can override its behavior to achieve our desired functionality.

While creating a custom UIDatepicker may seem like a daunting task, it provides us with more control over the appearance and behavior of our UI elements. This can be especially useful in applications where precise time selection is required.

By following this guide, you should now have a basic understanding of how to create your own custom UIDatepicker.

Last modified on 2024-04-11