UIDocumentPicker导航栏按钮在iOS 11中隐藏

Question

我在iOS 11的UIDocumentPicker导航栏中发现问题，完成，取消或编辑按钮是不可见的，当用户触摸它时，它会出现，即正常状态下的颜色是白色，甚至是更改UINavigationBar.appearnce().tintColor时，颜色仅在触摸时更改。

Answer 1

我不是在import matplotlib.pyplot as plt from mpl_toolkits.axes_grid1 import ImageGrid import numpy as np numberOfPlots = 3 data = [] for i in range(numberOfPlots): mean = i data.append(np.random.normal(mean, size=(100,100))) fig = plt.figure() grid = ImageGrid(fig, 111, nrows_ncols=(1,numberOfPlots), cbar_mode='single') ims = [] for i in range(numberOfPlots): ims.append(grid[i].imshow(data[i])) grid[i].set_title("Mean = " + str(i)) clims = [im.get_clim() for im in ims] vmin = min([clim[0] for clim in clims]) vmax = max([clim[1] for clim in clims]) for im in ims: im.set_clim(vmin=np.floor(vmin),vmax=np.ceil(vmax)) grid[0].cax.colorbar(ims[0]) # with cbar_mode="single", cax attribute of all axes are identical fig.show() 和viewWillAppear之间设置全局外观的忠实粉丝。外观API应仅在应用程序启动时使用。您可以通过将此代码放在viewWillDisappear中来重置UIDocumentPickerViewController的外观而不进行子类化，条形按钮将返回原始蓝色：

application:didFinishLaunchingWithOptions:

Answer 2

For unknown reason I figured out that if you make a subclass of UIDocumentPicker using Objective-C and set the [UINavigationBar appearance].tintColor = [UIColor black]; in viewWillAppear func, and reset it to your defaults in the viewWillDisappear, it works well.

But if you do the same steps using swift it wont.

Answer 3

对appearance使用带有黑色UINavigationBar的CustomDocumentPickerViewController和UIBarButtonItem

import UIKit

class CustomDocumentPickerViewController: UIDocumentPickerViewController {

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        UINavigationBar.appearance().tintColor = UIColor.black
        UIBarButtonItem.appearance().setTitleTextAttributes([NSForegroundColorAttributeName : UIColor.black], for: .normal)
    }

    override func viewWillDisappear(_ animated: Bool) {

        UINavigationBar.appearance().tintColor = UIColor.white // your color
        UIBarButtonItem.appearance().setTitleTextAttributes(nil, for: .normal)
        super.viewWillDisappear(animated)

    }

}