我需要一个 UIDatePicker 来仅选择月份和年份。我检查了类引用文件。看起来 UIDatePicker 是一个 UIView。我想象 UIPickerView 可能是一个 subview ，如果我可以捕获它，我可以隐藏该组件。但不是。那是不可能的。那我必须创建自己的自定义选择器吗？有什么想法吗？

最佳答案

这里有一个解决方案可以达到同样的效果。要使用这段代码，您应该在“身份检查器”的“自定义类”的 nib 文件中将 UIPickerView 替换为 CDatePickerViewEx。

.h文件

#import <UIKit/UIKit.h>

@interface CDatePickerViewEx : UIPickerView <UIPickerViewDelegate, UIPickerViewDataSource> 

@property (nonatomic, strong, readonly) NSDate *date;
-(void)selectToday;

@end

.m 文件

#import "CDatePickerViewEx.h"

// Identifiers of components
#define MONTH ( 0 )
#define YEAR ( 1 )    

// Identifies for component views
#define LABEL_TAG 43


@interface CDatePickerViewEx()

@property (nonatomic, strong) NSIndexPath *todayIndexPath;
@property (nonatomic, strong) NSArray *months;
@property (nonatomic, strong) NSArray *years;

-(NSArray *)nameOfYears;
-(NSArray *)nameOfMonths;
-(CGFloat)componentWidth;

-(UILabel *)labelForComponent:(NSInteger)component selected:(BOOL)selected;
-(NSString *)titleForRow:(NSInteger)row forComponent:(NSInteger)component;
-(NSIndexPath *)todayPath;
-(NSInteger)bigRowMonthCount;
-(NSInteger)bigRowYearCount;
-(NSString *)currentMonthName;
-(NSString *)currentYearName;

@end

@implementation CDatePickerViewEx

const NSInteger bigRowCount = 1000; 
const NSInteger minYear = 2008;
const NSInteger maxYear = 2030;
const CGFloat rowHeight = 44.f;
const NSInteger numberOfComponents = 2;

@synthesize todayIndexPath;
@synthesize months;
@synthesize years = _years;

-(void)awakeFromNib
{
    [super awakeFromNib];

    self.months = [self nameOfMonths];
    self.years = [self nameOfYears];
    self.todayIndexPath = [self todayPath];

    self.delegate = self;
    self.dataSource = self;

    [self selectToday];
}

-(NSDate *)date
{
    NSInteger monthCount = [self.months count];
    NSString *month = [self.months objectAtIndex:([self selectedRowInComponent:MONTH] % monthCount)];

    NSInteger yearCount = [self.years count];
    NSString *year = [self.years objectAtIndex:([self selectedRowInComponent:YEAR] % yearCount)];

    NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; [formatter setDateFormat:@"MMMM:yyyy"];
    NSDate *date = [formatter dateFromString:[NSString stringWithFormat:@"%@:%@", month, year]];
    return date;
}

#pragma mark - UIPickerViewDelegate
-(CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component
{
    return [self componentWidth];
}

-(UIView *)pickerView: (UIPickerView *)pickerView
            viewForRow: (NSInteger)row
          forComponent: (NSInteger)component
           reusingView: (UIView *)view
{   
    BOOL selected = NO;    
    if(component == MONTH)
    {
        NSInteger monthCount = [self.months count];
        NSString *monthName = [self.months objectAtIndex:(row % monthCount)]; 
        NSString *currentMonthName = [self currentMonthName];
        if([monthName isEqualToString:currentMonthName] == YES)
        {
            selected = YES;
        }
    }
    else
    {
        NSInteger yearCount = [self.years count];
        NSString *yearName = [self.years objectAtIndex:(row % yearCount)];
        NSString *currenrYearName  = [self currentYearName];
        if([yearName isEqualToString:currenrYearName] == YES)
        {
            selected = YES;
        }
    }

    UILabel *returnView = nil;
    if(view.tag == LABEL_TAG)
    {
        returnView = (UILabel *)view;
    }
    else 
    {
        returnView = [self labelForComponent: component selected: selected];
    }

    returnView.textColor = selected ? [UIColor blueColor] : [UIColor blackColor];
    returnView.text = [self titleForRow:row forComponent:component];
    return returnView;
}

-(CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
{
    return rowHeight;
}

#pragma mark - UIPickerViewDataSource
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    return numberOfComponents;
}

-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
    if(component == MONTH)
    {
        return [self bigRowMonthCount];
    }
    return [self bigRowYearCount];
}

#pragma mark - Util
-(NSInteger)bigRowMonthCount
{
    return [self.months count]  * bigRowCount;
}

-(NSInteger)bigRowYearCount
{
    return [self.years count]  * bigRowCount;
}

-(CGFloat)componentWidth
{
    return self.bounds.size.width / numberOfComponents;
}

-(NSString *)titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    if(component == MONTH)
    {
        NSInteger monthCount = [self.months count];
        return [self.months objectAtIndex:(row % monthCount)]; 
    }
    NSInteger yearCount = [self.years count];
    return [self.years objectAtIndex:(row % yearCount)];
}

-(UILabel *)labelForComponent:(NSInteger)component selected:(BOOL)selected
{
    CGRect frame = CGRectMake(0.f, 0.f, [self componentWidth],rowHeight);

    UILabel *label = [[UILabel alloc] initWithFrame:frame];
    label.textAlignment = UITextAlignmentCenter;
    label.backgroundColor = [UIColor clearColor];
    label.textColor = selected ? [UIColor blueColor] : [UIColor blackColor];
    label.font = [UIFont boldSystemFontOfSize:18.f];
    label.userInteractionEnabled = NO;

    label.tag = LABEL_TAG;

    return label;
}

-(NSArray *)nameOfMonths
{    
    NSDateFormatter *dateFormatter = [NSDateFormatter new];
    return [dateFormatter standaloneMonthSymbols];
}

-(NSArray *)nameOfYears
{
    NSMutableArray *years = [NSMutableArray array];

    for(NSInteger year = minYear; year <= maxYear; year++) 
    {
        NSString *yearStr = [NSString stringWithFormat:@"%i", year];
        [years addObject:yearStr];
    }
    return years;
}

-(void)selectToday
{
    [self selectRow: self.todayIndexPath.row
        inComponent: MONTH
           animated: NO];

    [self selectRow: self.todayIndexPath.section
        inComponent: YEAR
           animated: NO];
}

-(NSIndexPath *)todayPath // row - month ; section - year
{
    CGFloat row = 0.f;
    CGFloat section = 0.f;

    NSString *month = [self currentMonthName];
    NSString *year  = [self currentYearName];

    //set table on the middle
    for(NSString *cellMonth in self.months) 
    {
        if([cellMonth isEqualToString:month]) 
        {
            row = [self.months indexOfObject:cellMonth];
            row = row + [self bigRowMonthCount] / 2;
            break;
        }
    }

    for(NSString *cellYear in self.years) 
    {
        if([cellYear isEqualToString:year]) 
        {
            section = [self.years indexOfObject:cellYear];
            section = section + [self bigRowYearCount] / 2;
            break;
        }
    }

    return [NSIndexPath indexPathForRow:row inSection:section];
}

-(NSString *)currentMonthName
{
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setDateFormat:@"MMMM"];
    return [formatter stringFromDate:[NSDate date]];
}

-(NSString *)currentYearName
{
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setDateFormat:@"yyyy"];
    return [formatter stringFromDate:[NSDate date]];
}

@end

关于ios - UIDatePicker 选择月份和年份，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/3348247/