选择器视图显示和填充正确，但不具有交互性

Question

我在 Objective C 中创建了一个 Picker 视图，并用 NSArray 填充它，一切正常，它编译并显示在屏幕上，但选择器不执行任何操作。我想当用户像您期望的那样拖动手指时进行转动，但它无论如何都不会做出反应。

'小帮助？

我用于选择器的代码来自“开始 iPhone 开发”，但我在屏幕上有更多视图（地图视图和用于绘图的视图），为了清楚起见，我可以将所有代码转储到此处，因此我将限制它与我认为相关的内容。

//  SingleComponentPickerViewController.h
#import <UIKit/UIKit.h>


@interface SingleComponentPickerViewController : UIViewController <UIPickerViewDelegate, UIPickerViewDataSource> {
    IBOutlet    UIPickerView *singlePicker;
                NSArray *pickerData;
}
@property (nonatomic, retain) UIPickerView *singlePicker;
@property (nonatomic, retain) NSArray *pickerData;
- (IBAction)buttonPressed:(id)sender;
@end


//  SingleComponentPickerViewController.m

#import "SingleComponentPickerViewController.h"

@implementation SingleComponentPickerViewController
@synthesize singlePicker;
@synthesize pickerData;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
        // Initialization code
    }
    return self;
}
- (IBAction)buttonPressed:(id)sender
{
    NSInteger row = [singlePicker selectedRowInComponent:0];
    NSString *selected = [pickerData objectAtIndex:row];
    NSString *title = [[NSString alloc] initWithFormat:@"You selected %@!", selected];
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:title message:@"Thank you for choosing." delegate:nil cancelButtonTitle:@"You're Welcome" otherButtonTitles:nil];
    [alert show];
    [alert release];
    [title release];
}
- (void)viewDidLoad {
    NSArray *array = [[NSArray alloc] initWithObjects:@"Luke", @"Leia", @"Han", @"Chewbacca", @"Artoo", @"Threepio", @"Lando", nil];
    self.pickerData = array;
    [array release];

}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning]; // Releases the view if it doesn't have a superview
    // Release anything that's not essential, such as cached data
}

- (void)dealloc {
    [singlePicker release];
    [pickerData release];
    [super dealloc];
}
#pragma mark -
#pragma mark Picker Data Source Methods
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    return 1;
}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
    return [pickerData count];
}
#pragma mark Picker Delegate Methods
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    return [pickerData objectAtIndex:row];
}
@end

这就是代码，但我感觉问题更多地与视图的放置/交互方式有关。

Answer 1

将“useractionEnabled”属性设置为 true（在 IB 或代码中）？这应该是默认值。

但正如上面评论中提到的......一些代码可能会有所帮助:)