Question

我正在尝试查找UIGestureRecognizer在哪个目标上触发了哪个操作。很遗憾，UIGestureRecognizer上没有gesture.action或gesture.target的属性。我正在分析的手势是UIKit私有实施的一部分。

此处部分答案

stackOverFlow Question 20066315

Answer 1

这是一个代码片段，列出与手势识别器关联的所有目标/操作对：

Ivar targetsIvar = class_getInstanceVariable([UIGestureRecognizer class], "_targets");
id targetActionPairs = object_getIvar(gesture, targetsIvar);

Class targetActionPairClass = NSClassFromString(@"UIGestureRecognizerTarget");
Ivar targetIvar = class_getInstanceVariable(targetActionPairClass, "_target");
Ivar actionIvar = class_getInstanceVariable(targetActionPairClass, "_action");

for (id targetActionPair in targetActionPairs)
{
    id target = object_getIvar(targetActionPair, targetIvar);
    SEL action = (__bridge void *)object_getIvar(targetActionPair, actionIvar);

    NSLog(@"target=%@; action=%@", target, NSStringFromSelector(action));
}

请注意，您必须导入<objc/runtime.h>，并且这会使用私有的ivars和一个类，因此它可能会让您从App Store中被禁止。

Answer 2

我有一个不同的解决方案，这对我有用。这更像是一次设计更改......您无法从捕获的手势中访问目标。因此，在触碰发生时和平底锅开始之前，请保持对物体的引用。

@property (nonatomic, strong) UIButton *myTouchedButton; // reference to button

(void)init
{
    ...
    [card.button addTarget:self action:@selector(cardTouchDownInside:) forControlEvents:UIControlEventTouchDown];
    ...
}

-(void)cardTouchDownInside:(id)sender
{
    NSLog(@"touch down on object");
    self.myTouchedButton = (UIButton*)sender;
}

查找UIGestureRecognizer操作（选择器）名称和目标

2 个答案: