.Net 与 Cocoa 字符串格式

Question

我可以重现以下 C#/.NET:

//A
String.Format("There are {0} cats in my {1} and no {2}", 2, "house", "dogs");

in Objective-C/Cocoa:

//B
[NSString stringWithFormat:@"There are %d cats in my %@ and no %@", 2, "house", "dogs"];

但我不能这样做：

//C
String.Format("I have {0} dogs in my house.  My {0} dogs are very nice, but it is hard to walk {0} dogs at the same time.", numDogs);

in Objective-C:

//D
[NSString stringWithFormat:@"I have %d dogs in my house.  My %d dogs are very nice, but it is hard to walk %d dogs at the same time.", numDogs];

因为它使用 printf 格式或其他格式。有更先进的方法吗？有什么方法可以在字符串解析中进行 KVC 吗？

从技术上讲，这就是我想要的：

[player setValue:@"Jimmy" forKey@"PlayerName"];
//later
[NSString stringWithMagicFormat:@"<PlayerName> sat on a bench in the middle of winter, and <GenderPronoun> felt very cold." andPlayer:player];
// or
[NSString stringwithMagicFormat: playerEnteredStringWithTagInIt andPlayer:player];

但我会满足：

String.Format(playerEnteredStringWithTagInIt, player.PlayerName, player.PlayerGender, player.GenderPronoun, ...);

谢谢，

Answer 1

[NSString stringWithFormat:@"I have %1$d dogs in my house.  My %1$d dogs are very nice, but it is hard to walk %1$d dogs at the same time.", numDogs];

（参见man 3 printf。）

Answer 2

如果您使用 NSString 和 stringWithFormat:，那么我认为 C99 合规性并不真正适用：而 stringWithFormat: 与 printf 类似，它有自己的实现，并且已经存在了一段时间。

NSLocalizedString() 宏实际上会自动为您完成此操作。例如，假设我有以下代码：

 @implementation MDAppController

- (id)init {
    if (self = [super init]) {
        NSArray *catsArray = [NSArray array];
        NSString *string = [NSString stringWithFormat:
         NSLocalizedString(@"There are %lu %@ %@ in my home.", @"no comment"),
        (unsigned long)[catsArray count],
                            NSLocalizedString(@"red", @""),
                            NSLocalizedString(@"cats", @"")];
        NSLog(@"string == %@", string);
    }
    return self;
}

@end

中运行以下代码

如果我随后在终端/usr/bin/genstrings ~/Developer/NSLocalizedString/MDAppController.m -o ~/Desktop/Strings

（尽管我我更喜欢将窗口标题栏中的代理图标拖到我保存在 Dock 中的 AppleScript Droplet 上：GenerateStrings。它将生成的 .strings 文件（覆盖）写入 ~/Desktop/Strings/（如果需要，您可以通过将其拖放到 AppleScript 编辑器来编辑脚本）。

它将生成一个 UTF16 Localized.strings 文件，您可以将其添加到您的项目中。其中将包含以下内容：

English.lproj/Localizable.strings

/* No comment provided by engineer. */
"cats" = "cats";

/* No comment provided by engineer. */
"red" = "red";

/* no comment */
"There are %lu %@ %@ in my home." = "There are %1$lu %2$@ %3$@ in my home.";

将其复制到西班牙语项目子文件夹并根据需要更改项目的顺序（因为在西班牙语中形容词通常位于名词之后）：

Spanish.lproj/Localizable。 当英语是语言和字符串

/* No comment provided by engineer. */
"cats" = "gatos";

/* No comment provided by engineer. */
"red" = "rojos";

/* no comment */
"There are %lu %@ %@ in my home." = "Está %1$lu %3$@ %2$@ en mi casa.";

中我的主要（最重要）语言时文本偏好窗格：

1/20/2011 12:59:37 PM NSLocalizedString[1777] string == There are 0 red cats in my home.

当西班牙语是我的主要（最重要）语言时;文本偏好窗格：

1/20/2011 12:37:02 PM NSLocalizedString[1702] string == Está 0 gatos rojos en mi casa。

.strings 文件在某种意义上是键值对。

有关详细信息，请参阅 资源编程指南：字符串资源

Answer 3

我喜欢每个人的答案，但我只花了 15 分钟在文档中找到了我正在寻找的答案......叹息，RTM！这是我的解决方案，以防其他人正在寻找类似的东西。

// Put this in a category of NSString
- (NSString*) stringByReplacingOccurrencesOfKeysWithValues:(NSDictionary*)keyValuePairs
{
    NSString *fStr = self;
    if (keyValuePairs) {
        for (NSString *key in [keyValuePairs allKeys]) {
            NSString *value = [NSString stringWithFormat:@"%@",[keyValuePairs valueForKey:key]];
            fStr = [fStr stringByReplacingOccurrencesOfString:key withString:value];
        }
    }
    return fStr;
}

似乎工作正常，这是我的测试代码：

// testing NSString+Keys
NSMutableDictionary *mud = [NSMutableDictionary dictionaryWithCapacity:1];
[mud setValue:@"Jimmy" forKey:@"{PlayerName}"];
[mud setValue:[NSNumber numberWithInt:97] forKey:@"{HitPoints}"];
[mud setValue:[NSNumber numberWithFloat:1.0678f] forKey:@"{meters}"];
NSString *mystr = [@"Help me {PlayerName} before it is too late! I only have {HitPoints}hp left!  And I am {meters}m away! {PlayerName} hurry!" stringByReplacingOccurrencesOfKeysWithValues:mud];
NSLog(mystr);

输出是：

在为时已晚之前帮助我吉米！我只剩下97马力了！而我距离1.0678m！吉米快点！