也许你应该补充这个(在.pch文件#import后):

extern NSBundle* bundle; // Declared on Language.m

#ifdef NSLocalizedString
    #undef NSLocalizedString
    // Delete this line to avoid warning
    #warning "Undefining NSLocalizedString"
#endif

#define NSLocalizedString(key, comment) \
    [bundle localizedStringForKey:(key) value:@"" table:nil]

我最近也遇到了同样的问题，我不想启动和修补我的整个NSLocalizedString，也不想强迫应用程序重新启动新的语言工作。我希望一切都能按原样工作。

我的解决方案是动态地改变主bundle的类，并在那里加载适当的bundle:

头文件

@interface NSBundle (Language)
+(void)setLanguage:(NSString*)language;
@end

实现

#import <objc/runtime.h>

static const char _bundle=0;

@interface BundleEx : NSBundle
@end

@implementation BundleEx
-(NSString*)localizedStringForKey:(NSString *)key value:(NSString *)value table:(NSString *)tableName
{
    NSBundle* bundle=objc_getAssociatedObject(self, &_bundle);
    return bundle ? [bundle localizedStringForKey:key value:value table:tableName] : [super localizedStringForKey:key value:value table:tableName];
}
@end

@implementation NSBundle (Language)
+(void)setLanguage:(NSString*)language
{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^
    {
        object_setClass([NSBundle mainBundle],[BundleEx class]);
    });
    objc_setAssociatedObject([NSBundle mainBundle], &_bundle, language ? [NSBundle bundleWithPath:[[NSBundle mainBundle] pathForResource:language ofType:@"lproj"]] : nil, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
@end

所以基本上，当你的应用启动时，在你加载你的第一个控制器之前，简单地调用:

[NSBundle setLanguage:@"en"];

当你的用户在你的设置界面中改变他的首选语言时，只需再次调用它:

[NSBundle setLanguage:@"fr"];

要重置回系统默认值，只需传入nil:

[NSBundle setLanguage:nil];

享受……

对于那些需要Swift版本的人:

var bundleKey: UInt8 = 0

class AnyLanguageBundle: Bundle {

    override func localizedString(forKey key: String,
                                  value: String?,
                                  table tableName: String?) -> String {

        guard let path = objc_getAssociatedObject(self, &bundleKey) as? String,
              let bundle = Bundle(path: path) else {

            return super.localizedString(forKey: key, value: value, table: tableName)
            }

        return bundle.localizedString(forKey: key, value: value, table: tableName)
    }
}

extension Bundle {

    class func setLanguage(_ language: String) {

        defer {

            object_setClass(Bundle.main, AnyLanguageBundle.self)
        }

        objc_setAssociatedObject(Bundle.main, &bundleKey,    Bundle.main.path(forResource: language, ofType: "lproj"), .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
    }
}

你可以这样做:

NSString *bundlePath = [[NSBundle mainBundle] pathForResource:@"Localizable" ofType:@"strings" inDirectory:nil forLocalization:@"es"];


NSBundle *spanishBundle = [[NSBundle alloc] initWithPath:[bundlePath stringByDeletingLastPathComponent]];

NSLocalizedStringFromTableInBundle(@"House", nil, spanishBundle, nil):

你觉得Swift 3的这个解决方案怎么样?

extension String {

    func localized(forLanguage language: String = Locale.preferredLanguages.first!.components(separatedBy: "-").first!) -> String {

        guard let path = Bundle.main.path(forResource: language == "en" ? "Base" : language, ofType: "lproj") else {

            let basePath = Bundle.main.path(forResource: "Base", ofType: "lproj")!

            return Bundle(path: basePath)!.localizedString(forKey: self, value: "", table: nil)
        }

        return Bundle(path: path)!.localizedString(forKey: self, value: "", table: nil)
    }
}

简单的用法:

"report".localized(forLanguage: "pl") //forced language
"report".localized() //default language selected by user in settings, in case when your app doesnt support selected lanaguage, the default one is selected, here is an english.

根据Tudorizer的回答，在不离开或重新启动应用程序的情况下更改语言。

使用类来访问首选语言，而不是宏，以检查是否存在特定的语言代码。

下面是一个类，用于获取当前在iOS 9中工作的语言包:

@implementation OSLocalization

+ (NSBundle *)currentLanguageBundle
{
    // Default language incase an unsupported language is found
    NSString *language = @"en";

    if ([NSLocale preferredLanguages].count) {
        // Check first object to be of type "en","es" etc
        // Codes seen by my eyes: "en-US","en","es-US","es" etc

        NSString *letterCode = [[NSLocale preferredLanguages] objectAtIndex:0];

        if ([letterCode rangeOfString:@"en"].location != NSNotFound) {
            // English
            language = @"en";
        } else if ([letterCode rangeOfString:@"es"].location != NSNotFound) {
            // Spanish
            language = @"es";
        } else if ([letterCode rangeOfString:@"fr"].location != NSNotFound) {
            // French
            language = @"fr";
        } // Add more if needed
    }

    return [NSBundle bundleWithPath:[[NSBundle mainBundle] pathForResource:language ofType:@"lproj"]];
}

/// Check if preferred language is English
+ (BOOL)isCurrentLanguageEnglish
{
    if (![NSLocale preferredLanguages].count) {
        // Just incase check for no items in array
        return YES;
    }

    if ([[[NSLocale preferredLanguages] objectAtIndex:0] rangeOfString:@"en"].location == NSNotFound) {
        // No letter code for english found
        return NO;
    } else {
        // Tis English
        return YES;
    }
}

/*  Swap language between English & Spanish
 *  Could send a string argument to directly pass the new language
 */
+ (void)changeCurrentLanguage
{
    if ([self isCurrentLanguageEnglish]) {
        [[NSUserDefaults standardUserDefaults] setObject:@[@"es"] forKey:@"AppleLanguages"];
    } else {
        [[NSUserDefaults standardUserDefaults] setObject:@[@"en"] forKey:@"AppleLanguages"];
    }
}
@end

使用上面的类来引用一个字符串文件/图像/视频/等等:

// Access a localized image
[[OSLocalization currentLanguageBundle] pathForResource:@"my_image_name.png" ofType:nil]
// Access  a localized string from Localizable.strings file
NSLocalizedStringFromTableInBundle(@"StringKey", nil, [OSLocalization currentLanguageBundle], @"comment")

像下面这样inline更改language或更新上面类中的"changeCurrentLanguage"方法，以获取引用新语言的字符串参数。

[[NSUserDefaults standardUserDefaults] setObject:@[@"es"] forKey:@"AppleLanguages"];

斯威夫特版本:

NSUserDefaults.standardUserDefaults().setObject(["fr"], forKey: "AppleLanguages")
NSUserDefaults.standardUserDefaults().synchronize()