通过委托为另一个类中的手势识别器调用选择器

Question

我有一个自定义视图，它使用一个手势识别器来调用方法handleSingleTap。如果手势识别器和它调用的选择器的设置位于相同的自定义视图(CircleView).However中，那么这很好，我需要viewController中的handleSingleTap方法，所以我(1)在自定义视图(CircleView)中创建了一个协议，(2)在视图中创建了委托属性，当我(3)创建手势识别器时，我为handleSingleTap的目标设置了self.delegate (而不是最初的self )。在viewController.h中，(4)我说它符合协议，并声明了方法handleSingleTap。在视图控制器的.m文件中，我为自定义视图(CircleView)创建了一个属性，然后在.m文件的viewDidLoad中，将self设置为自定义视图的委托。但是，当我点击自定义视图中的圆圈时，handleSingleTap方法永远不会在viewController中被调用。

您能解释为什么选择器handleSingleTap没有在viewController中被调用吗？

1)创建的协议

@protocol CircleViewDelegate <NSObject>
-(void)handleSingleTap:(UITapGestureRecognizer *) tapper;

@end

2)创建委托属性

@property (nonatomic, weak) id <CircleViewDelegate> delegate;

在CircleView 3中)创建带有目标self.delegate的手势识别器

-(void)setUpGestureRecognizers{

    UITapGestureRecognizer *singleFingerTap =
    [[UITapGestureRecognizer alloc] initWithTarget:self.delegate action:@selector(handleSingleTap:)];
    singleFingerTap.numberOfTapsRequired=1;
    [self addGestureRecognizer:singleFingerTap]; 
}

4)在viewController.h中，

   @interface ViewController : UIViewController <UIImagePickerControllerDelegate, UINavigationControllerDelegate, CircleViewDelegate>
    -(void)handleSingleTap:(UITapGestureRecognizer *) tapper;

在viewController.m中

@property (strong, nonatomic) CircleView *overlay;

viewDidLoad

self.overlay.delegate = self;

viewController中的这个方法没有被调用

-(void)handleSingleTap:(UITapGestureRecognizer *) tapper {
     NSLog(@"never getting called");

}

Answer 1

这是你的解决方案之一。当然，你也可以用选择器来做，但是这也是肯定的。

.h

#import <UIKit/UIKit.h>

@protocol CircleViewDelegate <NSObject>

@required
- (void) circleViewPressedByOneTap;

@end

@interface CircleView : UIView

@property (nonatomic,assign) id<CircleViewDelegate> delegate;

- (id)initWithFrame:(CGRect)frame andWithDelegate:(id<CircleViewDelegate>)del;

@end

.m：

#import "CircleView.h"

@interface CircleView () <UIGestureRecognizerDelegate>

@end

@implementation CircleView

@synthesize delegate;

- (id)initWithFrame:(CGRect)frame andWithDelegate:(id<CircleViewDelegate>)del
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code
        delegate = del;
        [self setUpGestureRecognizers];
    }
    return self;
}

-(void)setUpGestureRecognizers{

    UITapGestureRecognizer *singleFingerTap =
    [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleSingleTap:)];
    singleFingerTap.numberOfTapsRequired=1;
    [self addGestureRecognizer:singleFingerTap];
}

-(void)handleSingleTap:(UITapGestureRecognizer *) tapper{
    [delegate circleViewPressedByOneTap];
}

在你的ViewController .m中：

#import "YouClassViewController.h"
#import "CircleView.h"

@interface YouClassViewController () <CircleViewDelegate>

@end

@implementation YouClassViewController


- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    CircleView* yourCircleView = [[CircleView alloc] initWithFrame:CGRectMake(0, 0, 50, 50) andWithDelegate:self];
    [self.view addSubview:yourCircleView];
}

- (void) circleViewPressedByOneTap{
    NSLog(@"Yeaah you pressed it ! :) ");
}