为 iOS 扩展 UIButton 时出现问题

Question

我尝试扩展 UIButton，但在 ColorButton 实现文件的初始化程序中不断收到“EXC_BAD_ACCESS”。

ColorButton 的标题。

#import <Foundation/Foundation.h>


@interface ColorButton : UIButton {
    UIImage * originalImage;
}

@property (nonatomic,readonly) NSString * buttonName;

-(id) initButtonWithName:(NSString *) color;
-(void) setOriginalImage;
-(void) setImage:(UIImage *) image;
@end

颜色按钮实现

#import "ColorButton.h"

@implementation ColorButton

@synthesize buttonName;

-(id) initButtonWithName:(NSString *) color {
    if ((self = (ColorButton *)[UIButton buttonWithType:UIButtonTypeCustom])) {
        buttonName = color;
        [self setTitle:buttonName forState:UIControlStateNormal]; //This is the line of the "EXC_BAD_ACCESS" error.
        [self setBackgroundImage:[self backgroundImageForDevice:color] forState:UIControlStateNormal]; // This line gets the error too. If I comment the line before it out.
    }
    return self;
}

-(UIImage *) backgroundImageForDevice:(NSString *) color {
        color = [color stringByAppendingString:@"Bubble"];
    if ([[[UIDevice currentDevice] model] isEqualToString:@"iPad"] ||[[[UIDevice currentDevice] model] isEqualToString:@"iPad Simulator"]) {
        color = [color stringByAppendingString:@"-iPad"];
    }
    color = [color stringByAppendingString:@".png"];
    return [UIImage imageNamed:color];
}

-(void) setOriginalImage {
    [self setBackgroundImage:originalImage forState:UIControlStateNormal];
}

-(void) setImage:(UIImage *) image {
    [self setImage:image forState:UIControlStateNormal];
}
@end

Answer 1

您无法将 UIButton * 实例强制转换为 ColorButton * 类型。

您必须记住，ColorButton 继承自 UIButton，而不是相反，这意味着 ColorButton 的每个实例都是一个 UIButton 根据定义，但反之则不然。

这是另一个具有完全相同相同问题的线程:)

目标 C：从 UIButton 类的子类创建的按钮不起作用