结论1、签名的参量类型伪造不正确会导致崩溃。
结论二、签名个数不对可能会导致参量丢失。
结论三：在签名配置正确的情况下，系统会将函数调用的所有信息打包到NSInvocation准备转发；
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[self performSelector:@selector(goooo:) withObject:@"dddd" afterDelay:0];
[self performSelector:@selector(exgoo) withObject:@"aa" withObject:@"bb"];
}
- (NSMethodSignature *)methodSignatureForSelector:(SEL)aSelector
{
//NSMethodSignature *signature = [NSMethodSignature signatureWithObjCTypes:"v@:@"];
NSMethodSignature *signature = [NSMethodSignature signatureWithObjCTypes:"v@:f"];
return signature;
}
- (void)forwardInvocation:(NSInvocation *)anInvocation
{
__autoreleasing id returnObj;
[anInvocation getArgument:&returnObj atIndex:(NSInteger)2];
//dddd
//aa
NSLog(NSStringFromSelector(anInvocation.selector));
//exgoo::
//goooo:
NSLog(returnObj);
}
NSInvocation的调用有2个方法，target参数可以直接设置target属性或者设置为第一个参数，如果不设置则调用第二个方法将target传入
// 测试
// 构建对象 测试UILabel的setText:方法
UILabel *myObj = [UILabel new];
NSLog(@"invocation执行前myObj.text=%@", myObj.text);
// 构建方法签名返回类型void编码为v，对象UILabel类型编码为@，SEL编码为:，参数类型NSString编码为@
NSMethodSignature *myMethodSignature = [NSMethodSignature signatureWithObjCTypes:"v@:@"];
// 构建NSInvocation
NSInvocation *myInvocation = [NSInvocation invocationWithMethodSignature:myMethodSignature];
// 设置第1个参数
myInvocation.target = myObj;
// 设置第2个参数
myInvocation.selector = @selector(setText:);
// 设置第3个参数
NSString *newText = @"change new text";
[myInvocation setArgument:&newText atIndex:2];
[myInvocation retainArguments];
// 执行
[myInvocation invoke];
NSLog(@"invocation执行后myObj.text=%@", myObj.text);作者：不上火喝纯净水
链接：https://www.jianshu.com/p/49151a79ac6a
來源：简书
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