iOS 通过 runtime Method 方式实现UIButton 间隔一定时间响应点击事件
一、背景
当我们在开发过程中，会遇到需要把button的频繁点击事件让有一定时间间隔的去响应。
二、实现过程中会用到
2.1
Method 中的一些方法
比如：
/**
* Returns a specified instance method for a given class.
*
* @param cls The class you want to inspect.
* @param name The selector of the method you want to retrieve.
*
* @return The method that corresponds to the implementation of the selector specified by
* \e name for the class specified by \e cls, or \c NULL if the specified class or its
* superclasses do not contain an instance method with the specified selector.
*
* @note This function searches superclasses for implementations, whereas \c class_copyMethodList does not.
*/
OBJC_EXPORT Method _Nullable
class_getInstanceMethod(Class _Nullable cls, SEL _Nonnull name)
OBJC_AVAILABLE(10.0, 2.0, 9.0, 1.0, 2.0);
/**
* Adds a new method to a class with a given name and implementation.
*
* @param cls The class to which to add a method.
* @param name A selector that specifies the name of the method being added.
* @param imp A function which is the implementation of the new method. The function must take at least two arguments—self and _cmd.
* @param types An array of characters that describe the types of the arguments to the method.
*
* @return YES if the method was added successfully, otherwise NO
* (for example, the class already contains a method implementation with that name).
*
* @note class_addMethod will add an override of a superclass's implementation,
* but will not replace an existing implementation in this class.
* To change an existing implementation, use method_setImplementation.
*/
OBJC_EXPORT BOOL
class_addMethod(Class _Nullable cls, SEL _Nonnull name, IMP _Nonnull imp,
const char * _Nullable types)
OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
/**
* Replaces the implementation of a method for a given class.
*
* @param cls The class you want to modify.
* @param name A selector that identifies the method whose implementation you want to replace.
* @param imp The new implementation for the method identified by name for the class identified by cls.
* @param types An array of characters that describe the types of the arguments to the method.
* Since the function must take at least two arguments—self and _cmd, the second and third characters
* must be “@:” (the first character is the return type).
*
* @return The previous implementation of the method identified by \e name for the class identified by \e cls.
*
* @note This function behaves in two different ways:
* - If the method identified by \e name does not yet exist, it is added as if \c class_addMethod were called.
* The type encoding specified by \e types is used as given.
* - If the method identified by \e name does exist, its \c IMP is replaced as if \c method_setImplementation were called.
* The type encoding specified by \e types is ignored.
*/
OBJC_EXPORT IMP _Nullable
class_replaceMethod(Class _Nullable cls, SEL _Nonnull name, IMP _Nonnull imp,
const char * _Nullable types)
OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
/**
* Exchanges the implementations of two methods.
*
* @param m1 Method to exchange with second method.
* @param m2 Method to exchange with first method.
*
* @note This is an atomic version of the following:
* \code
* IMP imp1 = method_getImplementation(m1);
* IMP imp2 = method_getImplementation(m2);
* method_setImplementation(m1, imp2);
* method_setImplementation(m2, imp1);
* \endcode
*/
OBJC_EXPORT void
method_exchangeImplementations(Method _Nonnull m1, Method _Nonnull m2)
OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0, 2.0);
等一些方法；
对 相应的Method 方法做一个简单的解释：
struct objc_method_description_list {
int count;
struct objc_method_description list[1];
};
struct objc_protocol_list {
struct objc_protocol_list * _Nullable next;
long count;
__unsafe_unretained Protocol * _Nullable list[1];
};
struct objc_category {
char * _Nonnull category_name OBJC2_UNAVAILABLE;
char * _Nonnull class_name OBJC2_UNAVAILABLE;
struct objc_method_list * _Nullable instance_methods OBJC2_UNAVAILABLE;
struct objc_method_list * _Nullable class_methods OBJC2_UNAVAILABLE;
struct objc_protocol_list * _Nullable protocols OBJC2_UNAVAILABLE;
} OBJC2_UNAVAILABLE;
struct objc_ivar {
char * _Nullable ivar_name OBJC2_UNAVAILABLE;
char * _Nullable ivar_type OBJC2_UNAVAILABLE;
int ivar_offset OBJC2_UNAVAILABLE;
#ifdef __LP64__
int space OBJC2_UNAVAILABLE;
#endif
} OBJC2_UNAVAILABLE;
struct objc_ivar_list {
int ivar_count OBJC2_UNAVAILABLE;
#ifdef __LP64__
int space OBJC2_UNAVAILABLE;
#endif
/* variable length structure */
struct objc_ivar ivar_list[1] OBJC2_UNAVAILABLE;
} OBJC2_UNAVAILABLE;
struct objc_method {
SEL _Nonnull method_name OBJC2_UNAVAILABLE;
char * _Nullable method_types OBJC2_UNAVAILABLE;
IMP _Nonnull method_imp OBJC2_UNAVAILABLE;
} OBJC2_UNAVAILABLE;
struct objc_method_list {
struct objc_method_list * _Nullable obsolete OBJC2_UNAVAILABLE;
int method_count OBJC2_UNAVAILABLE;
#ifdef __LP64__
int space OBJC2_UNAVAILABLE;
#endif
/* variable length structure */
struct objc_method method_list[1] OBJC2_UNAVAILABLE;
}
可以看到以上一些都是结构体。
下面对常用的方法的注释：
//判断类中是否包含某个方法的实现
BOOL class_respondsToSelector(Class cls, SEL sel)
//获取类中的方法列表
Method *class_copyMethodList(Class cls, unsigned int *outCount)
//为类添加新的方法,如果方法该方法已存在则返回NO
BOOL class_addMethod(Class cls, SEL name, IMP imp, const char *types)
//替换类中已有方法的实现,如果该方法不存在添加该方法
IMP class_replaceMethod(Class cls, SEL name, IMP imp, const char *types)
//获取类中的某个实例方法(减号方法)
Method class_getInstanceMethod(Class cls, SEL name)
//获取类中的某个类方法(加号方法)
Method class_getClassMethod(Class cls, SEL name)
//获取类中的方法实现
IMP class_getMethodImplementation(Class cls, SEL name)
//获取类中的方法的实现,该方法的返回值类型为struct
IMP class_getMethodImplementation_stret(Class cls, SEL name)
//获取Method中的SEL
SEL method_getName(Method m)
//获取Method中的IMP
IMP method_getImplementation(Method m)
//获取方法的Type字符串(包含参数类型和返回值类型)
const char *method_getTypeEncoding(Method m)
//获取参数个数
unsigned int method_getNumberOfArguments(Method m)
//获取返回值类型字符串
char *method_copyReturnType(Method m)
//获取方法中第n个参数的Type
char *method_copyArgumentType(Method m, unsigned int index)
//获取Method的描述
struct objc_method_description *method_getDescription(Method m)
//设置Method的IMP
IMP method_setImplementation(Method m, IMP imp)
//替换Method
void method_exchangeImplementations(Method m1, Method m2)
//获取SEL的名称
const char *sel_getName(SEL sel)
//注册一个SEL
SEL sel_registerName(const char *str)
//判断两个SEL对象是否相同
BOOL sel_isEqual(SEL lhs, SEL rhs)
//通过块创建函数指针,block的形式为^ReturnType(id self,参数,...)
IMP imp_implementationWithBlock(id block)
//获取IMP中的block
id imp_getBlock(IMP anImp)
//移出IMP中的block
BOOL imp_removeBlock(IMP anImp)
//调用target对象的sel方法
id objc_msgSend(id target, SEL sel, 参数列表...)
2.2
objc 的一些方法，建议观看这篇文章，这里不再阐述。
三、
废话少说，直接上代码：
+ (void)load {
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
// 创建方法名
SEL selA = @selector(sendAction:to:forEvent:);
SEL selB = @selector(tempSendAction:to:forEvent:);
// 获取对象方法
Method methodA = class_getInstanceMethod(self, selA);
Method methodB = class_getInstanceMethod(self, selB);
//将 methodB的实现 添加到系统方法中 即 将 methodA方法指针添加成 方法methodB的 返回值表示是否添加成功
BOOL isAddMethodB = class_addMethod(self, selA, method_getImplementation(methodB), method_getTypeEncoding(methodB));
if (isAddMethodB) {
// 添加成功了 说明 本类中不存在methodB
// 此时必须将方法b的实现指针换成方法A的，否则 b方法将没有实现。
class_replaceMethod(self, selB, method_getImplementation(methodA), method_getTypeEncoding(methodA));
}else {
// 添加失败，说明 本类中已经有methodB
// 只需要 把 methodA 的实现 替换成 methodB
method_exchangeImplementations(methodA, methodB);
}
});
}
- (void)tempSendAction:(SEL)action to:(id)target forEvent:(UIEvent *)event {
if ([NSStringFromClass(self.class) isEqualToString:@"JWDIntervalButton"]) {
self.timeInterval = self.timeInterval == 0 ? defaultInterval : self.timeInterval;
if (self.isIgnoreEvent) {
return;
}else if (self.timeInterval > 0) {
[self performSelector:@selector(resetState) withObject:nil afterDelay:self.timeInterval inModes:@[NSRunLoopCommonModes,NSDefaultRunLoopMode]];
}
}
self.isIgnoreEvent = YES;
//此处 methodA和methodB方法IMP互换了，实际上执行 sendAction；所以不会死循环
[self tempSendAction:action to:target forEvent:event];
}
// 不可点击
- (void)resetState {
[self setIsIgnoreEvent:NO];
}
//runtime 动态绑定 属性
- (void)setIsIgnoreEvent:(BOOL)isIgnoreEvent {
// 注意BOOL类型 需要用OBJC_ASSOCIATION_RETAIN_NONATOMIC 不要用错，否则set方法会赋值出错
objc_setAssociatedObject(self, @selector(isIgnoreEvent), @(isIgnoreEvent), OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (BOOL)isIgnoreEvent {
return [objc_getAssociatedObject(self, _cmd) boolValue];
}
- (void)setTimeInterval:(NSTimeInterval)timeInterval {
objc_setAssociatedObject(self, @selector(timeInterval), @(timeInterval), OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (NSTimeInterval)timeInterval {
return [objc_getAssociatedObject(self, _cmd) doubleValue];
}
最后附上git地址：demo
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