performSelector

performSelector 的一些问题

代码

- (void)methodNoReturnAndArgument {
    NSLog(@"%@",NSStringFromSelector(_cmd));
}
- (void)methodNoReturnWithArgument:(id)obj {
    NSLog(@"argument:%@",obj);
    NSLog(@"%@",NSStringFromSelector(_cmd));
}
- (id)methodReturnWithArgument:(id)obj {
    NSLog(@"argument:%@",obj);
    NSLog(@"return:%@",obj);
    return obj;
}

    SEL sel1 = @selector(methodNoReturnAndArgument);
    SEL sel2 = @selector(methodNoReturnWithArgument:);
    SEL sel3 = @selector(methodReturnWithArgument:);
    id obj1 = @"1";
    id obj2 = @"2";
    id obj3 = @"3";
    id ret1;
    id ret2;
    id ret3;
    void *a;
    [self performSelector:sel1];
    [self performSelector:sel1 withObject:nil];
    [self performSelector:sel1 withObject:obj1];
//    ret1 = [self performSelector:sel1 withObject:obj1]; // 崩溃
    /// 接受参数错误
    /// 下面这行转换就没有问题
    a = (__bridge void *)[self performSelector:sel1 withObject:obj1];
    
//        [self performSelector:sel2]; // 崩溃
    /// 有参数去没有传
    [self performSelector:sel2 withObject:nil];
    //    ret2 = [self performSelector:sel2 withObject:nil]; // 崩溃
    /// 接受参数错误
    ret2 = [self performSelector:sel2 withObject:obj2];
    
    //    [self performSelector:sel3];    // 崩溃
    [self performSelector:sel3 withObject:nil];
    ret3 = [self performSelector:sel3 withObject:nil];
    ret3 = [self performSelector:sel3 withObject:obj3];