UIPickerView 未正确显示数据（仅显示“？”）

Question

如果这个问题之前已经讨论过，请原谅我。
我在 UIPickerView 中显示数据时遇到问题，它只显示问号“？”。

头文件.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

好的，你的问题解决了，问题是委托方法不正确，

您使用的方法（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，（必须有效）

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