iOS开发教程之APP内部切换语言的实现方法

+ (void)load {
 static dispatch_once_t onceToken;
 dispatch_once(&onceToken, ^{
  //动态继承、交换，方法类似KVO，通过修改[NSBundle mainBundle]对象的isa指针，使其指向它的子类CLBundle，这样便可以调用子类的方法；其实这里也可以使用method_swizzling来交换mainBundle的实现，来动态判断，可以同样实现。
  object_setClass([NSBundle mainBundle], [CLBundle class]);
 });
}

- (NSString *)localizedStringForKey:(NSString *)key value:(NSString *)value table:(NSString *)tableName {
 if ([CLBundle cl_mainBundle]) {
  return [[CLBundle cl_mainBundle] localizedStringForKey:key value:value table:tableName];
 } else {
  return [super localizedStringForKey:key value:value table:tableName];
 }
}

+ (NSBundle *)cl_mainBundle {
 if ([NSBundle currentLanguage].length) {
  NSString *path = [[NSBundle mainBundle] pathForResource:[NSBundle currentLanguage] ofType:@"lproj"];
  if (path.length) {
   return [NSBundle bundleWithPath:path];
  }
 }
 return nil;
}

+ (NSString *)currentLanguage {
 return [CLLanguageManager userLanguage] ? : [NSLocale preferredLanguages].firstObject;
}

+ (void)setUserLanguage:(NSString *)userLanguage {
 //跟随手机系统
 if (!userLanguage.length) {
  [self resetSystemLanguage];
  return;
 }
 //用户自定义
 [[NSUserDefaults standardUserDefaults] setValue:userLanguage forKey:CLUserLanguageKey];
 [[NSUserDefaults standardUserDefaults] setValue:@[userLanguage] forKey:@"AppleLanguages"];
 [[NSUserDefaults standardUserDefaults] synchronize];
}

+ (NSString *)userLanguage {
 return [[NSUserDefaults standardUserDefaults] valueForKey:CLUserLanguageKey];
}


+ (void)resetSystemLanguage {
 [[NSUserDefaults standardUserDefaults] removeObjectForKey:CLUserLanguageKey];
 [[NSUserDefaults standardUserDefaults] setValue:nil forKey:@"AppleLanguages"];
 [[NSUserDefaults standardUserDefaults] synchronize];
}

[CLLanguageManager setUserLanguage:@"en"];
 CLTabbarController *tabbarController = [[CLTabbarController alloc] init];
tabbarController.selectedIndex = 3;
UINavigationController *navigationController = tabbarController.selectedViewController;
NSMutableArray *viewControllers = navigationController.viewControllers.mutableCopy;
 //取出我的页面，提前加载，解决返回按钮不变化
 CLMyController *me = (CLMyController *)[viewControllers firstObject];
[me loadViewIfNeeded];
 //新建设置语言页面
CLChangeLanguageController *languageController = [[CLChangeLanguageController alloc] init];
languageController.hidesBottomBarWhenPushed = YES;
[viewControllers addObject:languageController];
 //解决奇怪的动画bug。
dispatch_async(dispatch_get_main_queue(), ^{
 [UIApplication sharedApplication].keyWindow.rootViewController = tabbarController;
 navigationController.viewControllers = viewControllers;
 CLLog(@"已切换到语言 %@", [NSBundle currentLanguage]);
});