Выяснение, какие метасы не решены в программе Agda.

Если вы хотите стрелку назад, поэтому следующий код помещается в AppDelegate файл в метод didFinishLaunchingWithOptions.

For Objective-C

 [[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60) forBarMetrics:UIBarMetricsDefault];

For Swift

let BarButtonItemAppearance = UIBarButtonItem.appearance()
BarButtonItemAppearance.setTitleTextAttributes([NSForegroundColorAttributeName: UIColor.clear], for: .normal)

Еще одна опция приведена ниже.

В Objective C

self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil];

В Swift

self.navigationItem.backBarButtonItem = UIBarButtonItem(title:"", style:.plain, target:nil, action:nil)

UPDATE:

    let BarButtonItemAppearance = UIBarButtonItem.appearance()

    let attributes: [NSAttributedStringKey: Any] = [
    BarButtonItemAppearance.setTitleTextAttributes([NSForegroundColorAttributeName: UIColor.clear], for: .normal)
            NSAttributedStringKey.font: UIFont.systemFont(ofSize: 0.1),
            NSAttributedStringKey.foregroundColor: UIColor.clear]

    BarButtonItemAppearance.setTitleTextAttributes(attributes, for: .normal)
    BarButtonItemAppearance.setTitleTextAttributes(attributes, for: .highlighted)

UPDATE SWIFT 4.1:

    let attributes = [NSAttributedStringKey.font:  UIFont(name: "Helvetica-Bold", size: 0.1)!, NSAttributedStringKey.foregroundColor: UIColor.clear]

    BarButtonItemAppearance.setTitleTextAttributes(attributes, for: .normal)
    BarButtonItemAppearance.setTitleTextAttributes(attributes, for: .highlighted)

Использование Offset

UIBarButtonItem.appearance().setBackButtonTitlePositionAdjustment(UIOffsetMake(-1000, 0), for:UIBarMetrics.default)

Возможно, ваша проблема была решена.

Счастливое кодирование.