当我在 XCode 7.1 for iOS 9.1 上构建我的应用程序时出现空白屏幕

Question

我有用于构建应用程序的应用程序压缩包，但它们的文件非常过时。我已经修复了应用程序中的大部分问题，但有一个问题我不明白。问题在于以下代码：

- (NSUInteger)application:(UIApplication*)application supportedInterfaceOrientationsForWindow:(UIWindow*)window
{
    // iPhone doesn't support upside down by default, while the iPad does.  
    // Override to allow all orientations always, and let the root view     
    // controller decide what's allowed 
    //(the supported orientations mask gets intersected).
    NSUInteger supportedInterfaceOrientations = 
        (1 << UIInterfaceOrientationPortrait) | 
        (1 << UIInterfaceOrientationLandscapeLeft) | 
        (1 << UIInterfaceOrientationLandscapeRight) | 
        (1 << UIInterfaceOrientationPortraitUpsideDown);

    return supportedInterfaceOrientations;
}

我在构建它时遇到的错误是：

/Users/username/Desktop/Appfolder/platforms/ios/Appname/Classes/AppDelegate.m:138:1：'application:supportedInterfaceOrientationsForWindow:'的实现中的返回类型冲突：'UIInterfaceOrientationMask'（又名'enum UIInterfaceOrientationMask' ) vs 'NSUInteger' (又名'unsigned long')

Answer 1

尝试将第一行更改为：

- (UIInterfaceOrientationMask)application:(UIApplication*)application supportedInterfaceOrientationsForWindow:(UIWindow*)window

并查看是否可以修复警告。基本上唯一的改变是将返回值的类型从NSUInteger更改为UIInterfaceOrientationMask。

事实上，如果这样写，这个方法可能看起来更整洁：

- (UIInterfaceOrientationMask)application:(UIApplication*)application supportedInterfaceOrientationsForWindow:(UIWindow*)window
{
    // iPhone doesn't support upside down by default, while the iPad does.
    // Override to allow all orientations always, and let the root view
    // controller decide what's allowed
    //(the supported orientations mask gets intersected).
    NSUInteger supportedInterfaceOrientations =
        UIInterfaceOrientationMaskPortrait |
        UIInterfaceOrientationMaskLandscapeLeft |
        UIInterfaceOrientationMaskLandscapeRight |
        UIInterfaceOrientationMaskPortraitUpsideDown;

    return supportedInterfaceOrientations;
}