分离 UIAppearence 代码 [英] Separating UIAppearence code

问题描述

我想为我正在创建的应用程序添加主题.只需在 2 种颜色之间切换，我希望导航栏、工具栏等以所选颜色显示.

I want to implement add themes to an app I'm creating. Simply just switching between 2 colors and I want the navigation bars, tool bars etc. to appear in the selected color.

当应用首次加载时，我在 AppDelegate 的 didFinishLaunchingWithOptions 方法中应用一种颜色.

When the app first loads, I apply one color to in the didFinishLaunchingWithOptions method in the AppDelegate.

UIColor *blueTheme = [UIColor colorWithRed:80/255.0f green:192/255.0f blue:224/255.0f alpha:1.0f];
UIColor *pinkTheme = [UIColor colorWithRed:225/255.0f green:87/255.0f blue:150/255.0f alpha:1.0f];

[[UINavigationBar appearance] setBarTintColor:pinkTheme];
[[UIToolbar appearance] setBarTintColor:pinkTheme];

[[UINavigationBar appearance] setTintColor:[UIColor whiteColor]];

在第一个视图控制器中，我放置了一个分段控件来切换颜色.

And in the first view controller I have put a segmented control to switch the colors.

- (IBAction)themeChosen:(UISegmentedControl *)sender
{
    if (sender.selectedSegmentIndex == 0) {
        UIColor *blueTheme = [UIColor colorWithRed:80/255.0f green:192/255.0f blue:224/255.0f alpha:1.0f];

        [[UINavigationBar appearance] setBarTintColor:blueTheme];
        [[UIToolbar appearance] setBarTintColor:blueTheme];
    } else {
        UIColor *pinkTheme = [UIColor colorWithRed:225/255.0f green:87/255.0f blue:150/255.0f alpha:1.0f];

        [[UINavigationBar appearance] setBarTintColor:pinkTheme];
        [[UIToolbar appearance] setBarTintColor:pinkTheme];
    }
    [[UINavigationBar appearance] setTintColor:[UIColor whiteColor]];
}

假设默认主题是粉红色.我从分段控件切换到蓝色并推送到下一个视图控制器，那里还有一个 UIToolBar.新选择的颜色(蓝色)仅应用于 UIToolBar 而不是 UINavigationBar.

Say the default theme is pink. I switch to blue from the segmented control and push to the next view controller where there is a UIToolBar as well. The newly chosen color(blue) is applied only to the UIToolBar but not to the UINavigationBar.

有没有更好的方法来解决这个问题?另外我想把与主题相关的代码放在一个单独的类中，因为它重复了很多代码.我该怎么做?

Is there a better way to go about this? Also I'd like to put the code related to themes in a separate class because it repeats a lot of code. How do I do that?

谢谢.

推荐答案

您遇到的问题是由于UIAppearance 仅在下一次生效创建了一个 UI 控件.你的新 UIToolbar 呈现出新的外观，因为当你推送一个新的视图控制器时，它有一个全新的工具栏.你的 UINavigationBar 没有改变，因为它是在你的导航控制器视图创建时创建的，不会更新它的外观.

The problem you're having is due to the fact that UIAppearance only takes effect the next time a UI control is created. Your new UIToolbar takes on the new appearance because when you push a new viewcontroller it has a brand new toolbar. Your UINavigationBar is not changing, because it was created when your navigationcontroller's view was created, and won't update its appearance.

您还必须直接在您的 navigationController 的 navigationBar 上更新该属性.例如:

You'll have to also update the property directly on your navigationController's navigationBar. e.g.:

self.navigationController.navigationBar.barTintColor = blueTheme;

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