从 Apple iPhone SDK 中的 UIPickerview 选择数据时如何显示图像

Question

我有一个多组件选择器，带有两个单独的轮子，显示相关信息。我想根据选择的组件显示图像。例如：如果在两个轮子中都选择了“AA”，则会显示图像 AA。如果将右轮改为“B”，则会显示图像 AB。

提前感谢您的帮助。

问候，

Answer 1

你可以这样做：

#import <UIKit/UIKit.h>

@interface PickerController: UIViewController <UIPickerViewDelegate, UIPickerViewDataSource> {
    NSArray *titleStrings;
    UIPickerView *picker;
    UIImage *imageView;
}
@end

@implementation PickerController

- (id) init {
    if (self = [super init]) {
        titleStrings = [[NSArray alloc] initWithObjects:@"A", @"B", NULL];
        picker = [[UIPickerView alloc] initWithFrame:CGRectMake(0, 100, 320, 100)];
        picker.showsSelectionIndicator = YES;
        picker.delegate = self;
        picker.dataSource = self;
        [self.view addSubview:picker];
        imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"empty.png"]];
        imageView.frame = CGRectMake(0, 200, imageView.frame.size.width, imageView.frame.size.height);
        [self.view addSubview:imageView];
        [imageView release];
        [picker release];
    }
    return self;
}

- (void) dealloc {
    [titleStrings release];
    [super dealloc];
}

/* UIPickerViewDataSource */

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
    return 2;
}

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
    return 2;
}

/* UIPickerViewDelegate */

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

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    NSString *first = [titleStrings objectAtIndex:[pickerView selectedRowInComponent:0]];
    NSString *second = [titleStrings objectAtIndex:[pickerView selectedRowInComponent:1]]; 
    NSString *imageName = [[NSString alloc] initWithFormat:@"%@%@", first, second];
    imageView.image = [UIImage imageNamed:imageName];
    [imageName release];
    [imageView sizeToFit];
}

@end