Question

情况如下。我有一个名为“MyViewController”的视图控制器。在这个视图控制器中，我有一个使用子类按钮的文本编辑功能。 UIButton子类的名称是“ColorSwatch”

我在“ColorSwatch.h”子类中设置了委托/协议方法，如下所示。

//  ColorSwatch.h

#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>
#import <QuartzCore/QuartzCore.h>

@protocol ColorSwatchDelegate <NSObject>
- (void)fontColor:(UIColor *)color;
@end

@interface ColorSwatch : UIButton {
id <ColorSwatchDelegate> colorSwatchDelegate;
    CAGradientLayer *gradient;
    UIView *currentView;
    UIColor *fontColor;
}

@property (nonatomic, retain) id <ColorSwatchDelegate> colorSwatchDelegate;
@property (nonatomic, retain) CAGradientLayer *gradient; 
@property (nonatomic, retain) UIView *currentView;
@property (nonatomic, retain) UIColor *fontColor;

@end

现在我的“ColorSwatch.m”中有：

//  ColorSwatch.m

#import "ColorSwatch.h"
#import <QuartzCore/QuartzCore.h>
#import "MyViewController.h"

@implementation ColorSwatch

@synthesize gradient; 
@synthesize currentView;
@synthesize colorSwatchDelegate;
@synthesize fontColor;

-(void)setupView{
    "Makes the subclassed buttons pretty"
}

-(id)initWithFrame:(CGRect)frame{
    if((self = [super initWithFrame:frame])){

    }

    return self;
}

-(id)initWithCoder:(NSCoder *)aDecoder{
    if((self = [super initWithCoder:aDecoder])){
        [self setupView];
        MyViewController *mvc = [[MyViewController alloc] initWithNibName:
                                           @"MyViewController" bundle:nil];
        self.colorSwatchDelegate = mvc;
    }

    return self;
}


-(void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    [self magnify:view];
    fontColor = view.backgroundColor;
    [self.colorSwatchDelegate fontColor:fontColor];
}

- (void)magnify:(UIView *)view
{

}

- (void)dealloc
{
    [currentView release];
    [gradient release];
    [fontColor release];

    [super dealloc];
}

@end

在“MyViewController.h”中我有：

//  MyViewController.h

#import <UIKit/UIKit.h>
#import <QuartzCore/QuartzCore.h>
#import "ColorSwatch.h"


@interface MyViewController : UIViewController <ColorSwatchDelegate> {    

UITextField *photoLabelTextField;

}

@property (nonatomic, retain) IBOutlet UITextField *photoLabelTextField;

@end

在“MyViewController.m”中我有：

- (void)fontColor:(UIColor *)color
{
    NSLog(@"Selected Font Color");
    [self.photoLabelTextField setTextColor:color];
}

现在委托方法有效，这意味着当我点击颜色按钮时

NSLog(@"Selected Font Color");

消息被触发。但问题是我无法改变

[self.photoLabelTextField setTextColor:color];

属性。我已经尝试了很多改变属性的方法，我唯一可以做的就是发送NSLogs，我尝试在“MyViewController”类中更改属性没有任何反应。

如果有人能帮助我，我会很感激。

谢谢

Answer 1

问题是ColorSwatch将委托消息发送到MyViewController的悬空实例，它在initWithCoder：方法中错误地分配了它。

UIControls不应该将ViewControllers分配给他们的代表......反之亦然。

删除这些行...

// in ColorSwatch.m initWithCoder:
MyViewController *mvc = [[MyViewController alloc] initWithNibName:
                                           @"MyViewController" bundle:nil];
self.colorSwatchDelegate = mvc;

然后，在MyViewController.m ...

- (void)viewDidLoad {

    ColorSwatch *colorSwatchButton = [[ColorSwatch alloc] buttonWithType:UIButtonTypeCustom];

    // or place a ColorSwatch in the xib, on MyViewController's view... But not before you
    // you delete lines from initWithCoder, otherwise it's infinite circular allocation

    colorSwatchButton.frame = CGRectMake(/* ... */);
    colorSwatchButton addTarget:self action:@selector(csButtonPressed:) forControlEvent: UIControlEventTouchUpInside];
    // and so on...
    // now the important part:
    colorSwatchButton.colorSwatchDelegate = self;

    // see - the ViewController is in charge of allocation, sets itself up as the delegate
    [self.view addSubview:colorSwatchButton];
}

您可以使用IB。

，而不是在代码中构建按钮

第1步：让代表成为出口......

@property (nonatomic, retain) IBOutlet id <ColorSwatchDelegate> colorSwatchDelegate;

步骤2：在IB中绘制按钮，并将其类设置为ColorSwatch。然后你可以跳过我在viewDidLoad中写的代码。

步骤3：新放置的按钮现在应该在IB中显示出口。您可以像往常一样从那里拖动到MyViewController。

Answer 2

您的IBOutlet photoLabelTextField可能存在连接问题，您可能忘记将xib文字字段与photoLabelTextField

联系起来

UIButton Subclass委托方法的问题

2 个答案: