iOS自定义后退按钮转换不良

Question

我想在viewController中自定义后退按钮的图像。 所以对于这个viewController我有：

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    navigationController?.navigationBar.backIndicatorImage = #customImage
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    navigationController?.navigationBar.backIndicatorImage = #restoreImage
}

但是当我显示前一个viewController（调用viewWillDissapear）时，这个前一个viewController会等到它显示为设置图像（如果我swippe这不会发生）：

Answer 1

这里，图像的变化（imageSize 40 * 40）工作正常。你可以试试这个。

SecondViewController：

override func viewWillAppear(_ animated: Bool) {
    var backButtonImage = UIImage(named: "lineBack.png")
    UIBarButtonItem.appearance().setBackButtonBackgroundImage(backButtonImage, for: .normal, barMetrics: .default)
}

ThirdViewController：

override func viewWillAppear(_ animated: Bool) {
    var backButtonImage = UIImage(named: "roundBack.png")
    UIBarButtonItem.appearance().setBackButtonBackgroundImage(backButtonImage, for: .normal, barMetrics: .default)
}