iphone – UIPickerView不显示数据

我已经关注了几个youtube教程以及这里的建议,但我似乎无法让我的UIPickerView显示其数据.我正在使用三个数组填充选择器,我认为我已正确实现了代码,但显然有些错误.选择器正确显示元素数量,问题是它们都显示为“？”

我已经尝试将选择器的委托设置为self,但这也不起作用.提前致谢.

这是我的.h文件：

@interface BACcalcViewController : UIViewController<UIPickerViewDataSource,UIPickerViewDelegate>
@property(strong,nonatomic) IBOutlet UIPickerView *personInfoPicker;
@property(strong,nonatomic) NSArray *heightsArray;
@property(strong,nonatomic) NSArray *weightsArray;
@property(strong,nonatomic) NSArray *timeArray;
@end

这是我的.m文件：

@interface BACcalcViewController () <UIPickerViewDataSource,UIPickerViewDelegate>

@end

@implementation BACcalcViewController


@synthesize personInfoPicker,heightsArray,weightsArray,timeArray;
- (void)viewDidLoad
{

[super viewDidLoad];

heightsArray = [NSArray arrayWithObjects:
                         @"5ft 0in",@"5ft 1in",@"5ft 2in",@"5ft 3in",@"5ft 4in",@"5ft 5in",@"5ft 6in",@"5ft 7in",@"5ft 8in",@"5ft 9in",@"5ft 10in",@"5ft 11in",@"6ft 1in",@"6ft 2in",@"6ft 3in",@"6ft 4in",@"6ft 5in",@"6ft 6in",@"6ft 7in",@"6ft 8in",nil];

weightsArray = [NSArray arrayWithObjects:
                     @"100",@"110",@"120",@"130",@"140",@"150",@"160",@"170",@"180",@"190",@"200",@"210",@"220",@"230",@"240",@"250",@"260",nil];


timeArray = [NSArray arrayWithObjects:
             @"1",@"2",@"3",@"4",@"5",@"6",nil];
}



- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)personInfoPicker
{
    return 3;
}


- (NSInteger)pickerView:(UIPickerView *)personInfoPicker numberOfRowsInComponent: (NSInteger)component
{
    if (component == 0) 
        return [heightsArray count];
    else if (component == 1)
        return [weightsArray count];
    else
        return [timeArray count];
}

- (NSString *)pickerview:(UIPickerView *)personInfoPicker titleForRow:(NSInteger)row forComponent:(NSInteger)component
{    
    if (component == 0)
        return [heightsArray objectAtIndex:row];
    else if (component == 1)
        return [weightsArray objectAtIndex:row];
    else
        return [timeArray objectAtIndex:row];
}
@end

self.personInfoPicker.delegate = self;
self.personInfoPicker.dataSource = self;
[self.personInfoPicker reloadAllComponents];