iOS-替换的后退按钮太靠近边缘

我想全局更改导航栏的后退按钮，所以我需要这样做:

UIBarButtonItem.appearance().setBackButtonTitlePositionAdjustment(UIOffsetMake(-100, -5000), forBarMetrics: .Default)
        var backImage: UIImage = UIImage(named: "BackButton")!
        backImage = backImage.imageWithAlignmentRectInsets(UIEdgeInsetsMake(0, 0, 0, 20))
        UINavigationBar.appearance().backIndicatorImage = backImage
        UINavigationBar.appearance().backIndicatorTransitionMaskImage = backImage

但是背面图像太靠近屏幕左侧。如何将其向右移动？

最佳答案

只需调整实际图像即可。

extension UIImage {
    func imageWithInsets(insets: UIEdgeInsets) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(
        CGSizeMake(self.size.width + insets.left + insets.right,
                self.size.height + insets.top + insets.bottom), false, self.scale)
        let context = UIGraphicsGetCurrentContext()
        let origin = CGPoint(x: insets.left, y: insets.top)
        self.drawAtPoint(origin)
        let imageWithInsets = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return imageWithInsets
    }
}

对于Swift 4:

extension UIImage {
    func withInsets(_ insets: UIEdgeInsets) -> UIImage? {
        UIGraphicsBeginImageContextWithOptions(
            CGSize(width: size.width + insets.left + insets.right,
                   height: size.height + insets.top + insets.bottom),
            false,
            self.scale)

        let origin = CGPoint(x: insets.left, y: insets.top)
        self.draw(at: origin)
        let imageWithInsets = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return imageWithInsets
    }
}