app内切换语言

设置AppleLanguages字段，只会在下次启动App才会生效，在App启动后就已经生成了一个Bundle，里面识别好了对应着AppleLanguages的国际化文件，在App运行期间设置这个字段，是不生效的，所以我们去修改这个Bundle，写一个NSBundle的扩展。

.h

#import 

@interface NSBundle (Language)

+ (void)setLanguage:(NSString *)language;

@end

.m

#import "NSBundle+Language.h"
#import 

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

切换语言页面

#import "ViewController3.h"

#import "ZHTabBarController.h"

#import "NSBundle+Language.h"

@interface ViewController3 ()

@property (weak, nonatomic) IBOutlet UIButton *chineseBtn;

@property (weak, nonatomic) IBOutlet UIButton *englishBtn;

@end

@implementation ViewController3

- (void)viewDidLoad {

    [super viewDidLoad];

    

    [self.chineseBtn setTitle:NSLocalizedString(@"btn1", nil) forState:UIControlStateNormal];

    [self.englishBtn setTitle:NSLocalizedString(@"btn2", nil) forState:UIControlStateNormal];

}

- (IBAction)chineseBtnAction:(id)sender {

    [self changeLanguageTo:@"zh-Hans"];

}

- (IBAction)englishBtnAction:(id)sender {

    [self changeLanguageTo:@"en"];

}

- (void)changeLanguageTo:(NSString *)language {

    // 设置语言

    [NSBundle setLanguage:language];

    

    // 然后将设置好的语言存储好，下次进来直接加载

    [[NSUserDefaults standardUserDefaults] setObject:language forKey:@"myLanguage"];

    [[NSUserDefaults standardUserDefaults] synchronize];

    

    // 我们要把系统windown的rootViewController替换掉

    ZHTabBarController *tab = [[ZHTabBarController alloc] init];

    [UIApplication sharedApplication].keyWindow.rootViewController = tab;

    // 跳转到设置页

    tab.selectedIndex = 2;

}

appDelegate中的方法修改为：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    if ([[NSUserDefaults standardUserDefaults] objectForKey:@"myLanguage"] && ![[[NSUserDefaults standardUserDefaults] objectForKey:@"myLanguage"] isEqualToString:@""]) {
        [NSBundle setLanguage:[[NSUserDefaults standardUserDefaults] objectForKey:@"myLanguage"]];
    }

    // 创建主页面
    self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
    self.window.rootViewController = [[ZHTabBarController alloc] init];
    [self.window makeKeyAndVisible];

    return YES;
}