Question

我正在尝试创建一个像这样的定义

#define ICONS   [NSArray arrayWithObjects: [NSNumber numberWithFloat:33.0f], [NSNumber numberWithFloat:93.0f], [NSNumber numberWithFloat:149.0f], [NSNumber numberWithFloat:205.0f], [NSNumber numberWithFloat:314.0f], [NSNumber numberWithFloat:370.0f], [NSNumber numberWithFloat:426.0f], [NSNumber numberWithFloat:482.0f], nil]

但是，我想按行编写它 - 使代码可读，如

#define ICONS   [NSArray arrayWithObjects: 
[NSNumber numberWithFloat:33.0f], 
[NSNumber numberWithFloat:93.0f], 
[NSNumber numberWithFloat:149.0f], 
[NSNumber numberWithFloat:205.0f], 
[NSNumber numberWithFloat:314.0f],
[NSNumber numberWithFloat:370.0f],
[NSNumber numberWithFloat:426.0f],
[NSNumber numberWithFloat:482.0f],
nil]

但是当我打破行中的定义时，Xcode就像疯了一样大喊。

有没有办法打破界限并按我的意愿组织代码？

Answer 1

要跨行分割#define，您需要将\附加到这些行。

#define ICONS   [NSArray arrayWithObjects:               \
                    [NSNumber numberWithFloat:33.0f],    \
                    [NSNumber numberWithFloat:93.0f],    \
                    [NSNumber numberWithFloat:149.0f],   \ 
                    [NSNumber numberWithFloat:205.0f],   \
                    [NSNumber numberWithFloat:314.0f],   \
                    [NSNumber numberWithFloat:370.0f],   \
                    [NSNumber numberWithFloat:426.0f],   \
                    [NSNumber numberWithFloat:482.0f],   \
                    nil]

Answer 2

根据C规范，多行定义在每行的末尾需要一个'\'：

#define ICONS   [NSArray arrayWithObjects: \
                    [NSNumber numberWithFloat:33.0f],  \
                    [NSNumber numberWithFloat:93.0f],  \
                    [NSNumber numberWithFloat:149.0f], \
                    [NSNumber numberWithFloat:205.0f], \
                    [NSNumber numberWithFloat:314.0f], \
                    [NSNumber numberWithFloat:370.0f], \
                    [NSNumber numberWithFloat:426.0f], \
                    [NSNumber numberWithFloat:482.0f], \
                    nil]

试图使代码可读

2 个答案: