解耦合是一个老生常谈的话题，oc是一门动态语言，所以如何再.m文件中不导入其他.h文件 就可以调用一个类的方法，是非常诱人的一件事
1.通过performseletor来动态调用方法
Class clzz = NSClassFromString(@"Person");
id instance = [[clzz alloc]init];
SEL seletor = NSSelectorFromString(@"run:");
[instance performSelector:seletor withObject:nil];
但是这样xcode会有一个警告，具体原因大家可以去谷歌搜一把，
2.优化版本
Class clzz = NSClassFromString(@"Person");
id instance = [[clzz alloc]init];
SEL seletor = NSSelectorFromString(@"run:");
NSDictionary * dic = @{@"key":@"ss",@"key1":@"ss"};
IMP imp = [instance methodForSelector:seletor];
void (*func)(id, SEL,NSDictionary *) = (void *)imp;
func(instance, seletor,dic);
3.一种比较浪费时间 的方法 NSInvocation
Class clzz = NSClassFromString(@"Person");
id instance = [[clzz alloc]init];
NSMethodSignature *signture = [instance methodSignatureForSelector:@selector(run:)];
NSLog(@"num of arguments is %zd",signture.numberOfArguments);
NSLog(@"arguments0 is %s",[signture getArgumentTypeAtIndex:0]);
NSLog(@"arguments1 is %s",[signture getArgumentTypeAtIndex:1]);
NSLog(@"arguments2 is %s",[signture getArgumentTypeAtIndex:2]);
NSInvocation * invocation = [NSInvocati on invocationWithMethodSignature:signture];
NSDictionary * dic = @{@"key":@"ss",@"key1":@"ss"};
[invocation setArgument:&dic atIndex:2];
[invocation setTarget:instance];
[invocation setSelector:@selector(run:)];
[invocation invoke];
