UIPickerView无法正确显示数据（仅显示“？”）

Question

如果此问题已在前面讨论过，请原谅我。
我在UIPickerView中显示数据有问题，只显示问号“？”。

头file.h

#import <UIKit/UIKit.h> 
@interface CustomPickerViewController : UIViewController 
<UIPickerViewDelegate, UIPickerViewDataSource> { 
    NSMutableArray *arrayColors; 
} 

@property (strong, nonatomic) IBOutlet UIPickerView *kotaPicker; 

@end 

impl.m

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView { 
    return 1; 
} 

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component { 
    return [arrayColors count]; 
} 

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row { 
    return [arrayColors objectAtIndex:row]; 
} 

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component { 
    NSLog(@"The Data is %@", [arrayColors objectAtIndex:row]); 
} 
- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 
    arrayColors = [[NSMutableArray alloc] init]; 
    [arrayColors addObject:@"Red"]; 
    [arrayColors addObject:@"Orange"]; 
    [arrayColors addObject:@"Yellow"]; 
    [arrayColors addObject:@"Green"]; 
    [arrayColors addObject:@"Blue"]; 
    [arrayColors addObject:@"Indigo"]; 
    [arrayColors addObject:@"Violet"]; 
    // Do any additional setup after loading the view from its nib. 
} 

Answer 1

好了，你的问题就解决了，问题是不正确的委托方法，

的方法已经使用（用于加载数据）不是委托方法，

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row 

试试这个方法，而不是，（必须努力）

-(NSString *) pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{ 
    return [arrayColors objectAtIndex:row]; 
}