iOS-OC-Runtime使用小谈（objc_setAssociatedObject）
一.objc/runtime.h相关
Objecitve-C的重要特性是Runtime（运行时），在Interacting with the Runtime（交互运行）中，运行时函数部分，苹果给出了/usr/lib/libobjc.A.dylib库，这个共享库提供支持动态属性的objective - c语言，通过其接口，可以用于开发将其他语言运行于Objective-C上的中间层（桥接层），库里的函数定义为纯C语言。
二.objc/runtime.h使用
在这里我们主要举个简单的栗子��，通过新建一个UIButton的类别。
1.导入头文件
#import
2.新建一个Action的Category；
然后在.h中添加一个事件的Block，代码如下：
#import
typedef void (^ActionBlock)(UIButton *button);
@interface UIButton (Action)
@property (nonatomic,copy) ActionBlock actionBlock;
+ (UIButton *)createBtnWithFrame:(CGRect)frame title:(NSString *)title actionBlock:(ActionBlock)actionBlock;
@end 在这里我们创建了一个加方法，来创建一个按钮；
实现如下：
+ (UIButton *)createBtnWithFrame:(CGRect)frame title:(NSString *)title actionBlock:(ActionBlock)actionBlock{
UIButton *button = [[UIButton alloc]init];
button.frame = frame;
[button setTitle:title forState:UIControlStateNormal];
[button addTarget:button action:@selector(buttonClick:) forControlEvents:UIControlEventTouchUpInside];
objc_setAssociatedObject (button , &keyOfMethod, actionBlock, OBJC_ASSOCIATION_COPY_NONATOMIC);
return button;
}objc_setAssociatedObject(id object, const void *key, id value, objc_AssociationPolicy policy)
id object :表示关联者，是一个对象，变量名理所当然也是object
const void *key :获取被关联者的索引key
id value :被关联者，这里是一个block
objc_AssociationPolicy policy : 关联时采用的协议，有assign，retain，copy等协议，一般使用OBJC_ASSOCIATION_RETAIN_NONATOMIC
注意这里面我声明了两个索引KEY；
static NSString *keyOfMethod;
static NSString *keyOfBlock;- (void)buttonClick:(UIButton *)button{
//通过key获取被关联对象
//objc_getAssociatedObject(id object, const void *key)
ActionBlock block1 = (ActionBlock)objc_getAssociatedObject(button, &keyOfMethod);
if(block1){
block1(button);
}
ActionBlock block2 = (ActionBlock)objc_getAssociatedObject(button, &keyOfBlock);
if(block2){
block2(button);
}
}
- (void)setActionBlock:(ActionBlock)actionBlock{
objc_setAssociatedObject (self, &keyOfBlock, actionBlock, OBJC_ASSOCIATION_COPY_NONATOMIC );
}
- (ActionBlock)actionBlock{
return objc_getAssociatedObject (self ,&keyOfBlock);
}3.通过类别创建两个按钮
- (void)uiConfig{
//第一个按钮
UIButton *button1 = [UIButton createBtnWithFrame:CGRectMake((ScreenWidth - 100)/2, (ScreenHeight - 50)/2 - 50, 100, 50) title:@"按钮" actionBlock:^(UIButton *button) {
float r = random()%255/255.0;
float g = random()%255/255.0;
float b = random()%255/255.0;
self.view.backgroundColor = RGB(r, g, b);
}];
button1.backgroundColor = [UIColor lightGrayColor];
[self.view addSubview:button1];
//第二个按钮
UIButton *button2 = [UIButton createBtnWithFrame:CGRectMake((ScreenWidth - 100)/2, CGRectGetMaxY(button1.frame) + 50, 100, 50) title:@"按钮2" actionBlock:nil];
button2.actionBlock = ^(UIButton *button){
NSLog(@"---%@---",button.currentTitle);
};
button2.backgroundColor = [UIColor lightGrayColor];
[self.view addSubview:button2];
}4.获取苹果私有的APi
这里我们也可以通过runtime获取苹果私有的方法;
#pragma mark - 获取苹果私有的APi方法
- (void)getiOSPrivateAPi{
NSString *className = NSStringFromClass([UIView class]);
const char *cClassName = [className UTF8String];
id theClass = objc_getClass(cClassName);
unsigned int outCount;
Method *m = class_copyMethodList(theClass,&outCount);
NSLog(@"%d",outCount);
for (int i = 0; i注意，这里如果你想看其他的类，你把UIView换成你想要的类就好了；
5.DEMO下载地址
http://download.csdn.net/detail/u014220518/9659110