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我有一个奇怪的问题，UITapGestureRecognizer当要调用它的操作时，我总是以崩溃或抛出异常（无法识别的选择器）告终。我以前使用过手势识别器，但这次我将它附加到 aUIView上，它是 an 的一个属性NSObject（并且我正在使用对象的方法来构造视图）。以下是我正在做的一个最小示例：

我的对象.h：

#import <Foundation/Foundation.h>
@interface MyObject : NSObject
@property (nonatomic, strong) UIView *aView;
- (void)createViewWithFrame:(CGRect)frame;
@end

我的对象.m：

@interface MyObject ()
- (void)tapped:(id)sender; // Non-specific id type for brevity
@end

@implementation MyObject

- (void)tapped:(id)sender {
    NSLog(@"Tapped");
}

- (void)createViewWithFrame:(CGRect)frame {

    _aView = [[UIView alloc] initWithFrame:frame];
    self.aView.backgroundColor = [UIColor blueColor];
    self.aView.userInteractionEnabled = YES;
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]
                                    initWithTarget:self
                                    action:@selector(tapped:)];

    [self.aView addGestureRecognizer:tap];

}

视图控制器.m：

- (void)viewDidAppear:(BOOL)animated {

    [super viewDidAppear:animated];

    MyObject *obj = [[MyObject alloc] init];
    [obj createViewWithFrame:self.view.frame]; // Excuse poor frame - example only

    [self.view addSubview:obj.aView];
}

然后，当我点击视图时，应用程序在此处崩溃：

libobjc.A.dylib`objc_msgSend:
0x10e008c:  movl   8(%esp), %ecx
0x10e0090:  movl   4(%esp), %eax
0x10e0094:  testl  %eax, %eax
0x10e0096:  je     0x10e00e8                 ; objc_msgSend + 92
0x10e0098:  movl   (%eax), %edx
0x10e009a:  pushl  %edi
0x10e009b:  movl   8(%edx), %edi ; Thread 1: EXC_BAD_ACCESS (code=2, address=0x9)
0x10e009e:  pushl  %esi
0x10e009f:  movl   (%edi), %esi
0x10e00a1:  movl   %ecx, %edx

确切的崩溃点各不相同，我偶尔会收到无效的选择器错误。的NSLog，自然，永远不会发生。我之前（成功地）使用过手势识别器，这让我相信问题出在我的设置/设计中。谁能解释为什么手势识别器在这种情况下不能正常工作？

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1 回答 1

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The problem is with the scope of the MyObject, Declare the variable globally,

@property(nonatomic, strong) MyObject *obj;

in Your viewDidAppear, init and add the view 

self.obj = [[MyObject alloc] init];
[self.obj createViewWithFrame:self.view.frame]; 
[self.view addSubview:self.obj.aView];

That's it.

Now it is working !!

What was the problem ?, *the scope of the MyObject obj ends with the viewDidAppear method. When a tap is recognized, It is looking for the object to fire the method given. But the object is not there.

于 2013-05-05T03:11:06.493 回答