iOS: how to change Programmatically UI from LTR to RTL and viceversa

Question

I need to change language from English to arabic. All UI's in app developed programatically, I didn't used storyboard/xib for UI. I used localization string for converting language, but I am looking for UI view from LTR to RTL and vice versa.

what is the best way for language change and give me some ideas or samples

Answer 1

You can check the current language by this:

open class func isCurrentLanguageRTL(language:String) -> Bool {
        return Locale.characterDirection(forLanguage: language) == .rightToLeft
    }

Use this objective C code(Category) you can change your UI RTL:

#import <Foundation/Foundation.h>


@interface NSBundle (Language)

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

@end

Implement file :

#import "NSBundle+Language.h"
#import <UIKit/UIKit.h>
#import <objc/runtime.h>

static const char kBundleKey = 0;

@interface BundleEx : NSBundle

@end

@implementation BundleEx

- (NSString *)localizedStringForKey:(NSString *)key value:(NSString *)value table:(NSString *)tableName
{
    NSBundle *bundle = objc_getAssociatedObject(self, &kBundleKey);
    if (bundle) {
        return [bundle localizedStringForKey:key value:value table:tableName];
    }
    else {
        return [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]);
    });
    if ([self isCurrentLanguageRTL:language]) {
        if ([[[UIView alloc] init] respondsToSelector:@selector(setSemanticContentAttribute:)]) {
            [[UIView appearance] setSemanticContentAttribute:UISemanticContentAttributeForceRightToLeft];
            [[UITableView appearance] setSemanticContentAttribute:UISemanticContentAttributeForceRightToLeft];
            [[UINavigationBar appearance] setSemanticContentAttribute:UISemanticContentAttributeForceRightToLeft];
        }
    }else {
        if ([[[UIView alloc] init] respondsToSelector:@selector(setSemanticContentAttribute:)]) {
            [[UIView appearance] setSemanticContentAttribute:UISemanticContentAttributeForceLeftToRight];
            [[UITableView appearance] setSemanticContentAttribute:UISemanticContentAttributeForceLeftToRight];
            [[UINavigationBar appearance] setSemanticContentAttribute:UISemanticContentAttributeForceLeftToRight];
        }
    }
    [[NSUserDefaults standardUserDefaults] setBool:[self isCurrentLanguageRTL:language] forKey:@"AppleTextDirection"];
    [[NSUserDefaults standardUserDefaults] setBool:[self isCurrentLanguageRTL:language] forKey:@"NSForceRightToLeftWritingDirection"];
    [[NSUserDefaults standardUserDefaults] synchronize];

    id value = language ? [NSBundle bundleWithPath:[[NSBundle mainBundle] pathForResource:language ofType:@"lproj"]] : nil;
    objc_setAssociatedObject([NSBundle mainBundle], &kBundleKey, value, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

+ (BOOL)isCurrentLanguageRTL:(NSString *)code
{
    return ([NSLocale characterDirectionForLanguage:code] == NSLocaleLanguageDirectionRightToLeft);
}
@end

How to use:

Any type of language(like RTL, LTR) only call this bundle function in your code:

Bundle.setLanguage(<#Your Language code#>)

Note: You should add the #import "NSBundle+Language.h" in your bridging Header file.

If you use the left menu than in case of RTL you have to open the menu from right just checking the above swift function like:

<#YourClass#>.isCurrentLanguageRTL(<#Your Language Code#>) {
  //open your side menu from right
}