iOS 7更改UINavigationBar titleView alpha [英] iOS 7 Changing UINavigationBar titleView alpha

问题描述

所以我使用的UINavigationBar组件的iOS7，但不是UINavigationController本身。当我使用自定义导航控制器推新视图时，我想将标题的alpha更改为0.0，然后返回，但我似乎无法使其工作。

So I am using the UINavigationBar component of iOS7, but not the UINavigationController itself. When I push a new view with my custom navigation controller, I want to change the title's alpha to 0.0 and then back, but I can't seem to get it work.

我试图这样做

vc1.navBar.topItem.titleView.alpha = 0.1;

它似乎没有任何效果。

It doesn't seem to have any effect. Am I missing something here, is there a correct way to achieve this?

推荐答案

这是我该怎么办：

• 在推送的viewController的 viewWillAppear： to 0 using：

• In viewWillAppear: of the pushed viewController, I would set it the alpha to 0 using:

[self.navigationBar setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
                                                            [[UIColor whiteColor] colorWithAlphaComponent:0],
                                                            NSForegroundColorAttributeName,
                                                            [UIFont fontWithName:@"Helvetica-Bold" size:16.0],
                                                            NSFontAttributeName,
                                                             nil]];

在 viewDidAppear：它的alpha返回到1.这里你真的不需要设置它的alpha为1，只要设置为简单 [UIColor whiteColor] 会做的伎俩。

In viewDidAppear:, set it's alpha back to 1. Here you don't really need to set it's alpha to 1, just setting it to plain [UIColor whiteColor] will do the trick.

您可以做的另一件事是，切换 HIDDEN 2方法。

One other thing you could do is, toggle HIDDEN property in the 2 methods.

设置titleView的alpha不适用于我的情况，所以我使用上面的代码。它隐藏标题。如果你想要一个类似的效果与后退按钮，你设置的backButton的alpha使用 self.navigationItem.backBarButtonItem.customView.alpha =

Setting the alpha of the titleView did not work in my case so I used the above code. It hides the title. In case you want a similar effect with the back button, you set the alpha of the backButton using self.navigationItem.backBarButtonItem.customView.alpha =

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