ios - 宏无法按Objective-C的要求工作

Question

我有一个宏，非常简单，但是我不明白问题出在哪里？我收到错误消息:

“预期；表达后”

这是一个宏定义:

#define SEGCONTROL (itemArray, segmentedControl)      \
segmentedControl = [[SuperSegmentedControll alloc] initWithItems:itemArray];                                        \
segmentedControl.frame = CGRectMake(0, 0, 60, 28);     \
segmentedControl.layer.cornerRadius = 05;              \
[segmentedControl setTintColor:[UIColor colorWithRed:0.0/255.0 green:0.0/255.0 blue:102.0/255.0 alpha:1]];                  \
segmentedControl.backgroundColor = [UIColor colorWithRed:19.0/255.0 green:62.0/255.0 blue:137.0/255.0 alpha:1];              [segmentedControl setTitleTextAttributes:@{NSForegroundColorAttributeName:[UIColor whiteColor]} forState:UIControlStateNormal];                                \
[segmentedControl setTitleTextAttributes:               @{NSForegroundColorAttributeName:[UIColor whiteColor]} forState:UIControlStateSelected]; \

我打电话如下:

 NSArray *itemArray = [NSArray arrayWithObjects: @"Save", nil];
 SuperSegmentedControll *segmentedControl;
 SEGCONTROL(itemArray, segmentedControl);

我想将宏创建为很多地方都使用的类似代码。为了保存，请取消ETC。

Answer 1

失败的原因是因为#define宏名称SEGCONTROL与参数列表(itemArray, segmentedControl)之间存在空格。这实际上是将SEGCONTROL定义为(itemArray, segmentedControl)而不是代码段。要解决此问题，只需删除SEGCONTROL后的空格

#define SEGCONTROL(itemArray, segmentedControl) \ ...

但是，我强烈建议使用这种方法将反对，而不是在SuperSegmentedControll类上使用一个方法(该方法又应该有一个L和一个更具描述性的名称)来设置控件。这样，您将获得更好的编译器检查。像这样:

@implementation SuperSegmentedControl

- (instancetype)initWithItems:(NSArray *)items {
    self = [super initWithItems:items];
    if (self) {
        self.frame = CGRectMake(0, 0, 60, 28);
        self.layer.cornerRadius = 05;
        [self setTintColor:[UIColor colorWithRed:0.0/255.0 green:0.0/255.0 blue:102.0/255.0 alpha:1]];
        self.backgroundColor = [UIColor colorWithRed:19.0/255.0 green:62.0/255.0 blue:137.0/255.0 alpha:1];
        [self setTitleTextAttributes:@{NSForegroundColorAttributeName:[UIColor whiteColor]} forState:UIControlStateNormal];
        [self setTitleTextAttributes:@{NSForegroundColorAttributeName:[UIColor whiteColor]} forState:UIControlStateSelected];
    }
    return self;
}

@end

使用方法如下:

NSArray *itemArray = [NSArray arrayWithObjects: @"Save", nil];
SuperSegmentedControl *segmentedControl = [[SuperSegmentedControl alloc] initWithItems:itemArray];