ios 在主窗口上创建一个新的 UIWindow

To create a new UIWindow over the main window

提问by bohan

In my app I want to create a new UIWindowover the main UIWindow, And I wrote as following, but it don't works. first, i create a UIWindowas the main window, and then make it key and visible, and then create a new UIWindowoverlay, but nothing happens.

在我的应用程序中，我想UIWindow在主 UIWindow上创建一个新的，我写如下，但它不起作用。首先，我创建一个UIWindow作为主窗口，然后使它成为关键和可见，然后创建一个新的UIWindow覆盖，但没有任何反应。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.window.backgroundColor = [UIColor redColor];
    ViewController *vc = [[ViewController alloc]initWithNibName:@"ViewController" bundle:nil];
    self.window.rootViewController = vc;
    [self.window makeKeyAndVisible];
    UIWindow *window1 = [[UIWindow alloc] initWithFrame:CGRectMake(0, 0, 320, 320)];
    window1.backgroundColor = [UIColor redColor];
    window1.windowLevel = UIWindowLevelAlert;
    [window1 makeKeyAndVisible];
    return YES;
}

回答by bohan

UIWindow *window1 = [[UIWindow alloc] initWithFrame:CGRectMake(0, 0, 320, 320)];
window1.backgroundColor = [UIColor redColor];
window1.windowLevel = UIWindowLevelAlert;
[window1 makeKeyAndVisible];

Finally I know why it doesn't work, because window1 is a method var, and it will lost after the method executed. So I declare a new @property for it, as

终于知道为什么不行了，因为window1是一个方法var，执行完方法就会丢失。所以我为它声明一个新的@property，作为

@property (strong, nonatomic) UIWindow *window2;

and change the code like

并更改代码，如

UIWindow *window2 = [[UIWindow alloc] initWithFrame:CGRectMake(0, 80, 320, 320)];
window2.backgroundColor = [UIColor redColor];
window2.windowLevel = UIWindowLevelAlert;
self.window2 = window2;
[window2 makeKeyAndVisible];

it works!

有用！

回答by SwiftArchitect

Xcode 8 + Swift

Xcode 8 + 斯威夫特

class ViewController: UIViewController {
    var coveringWindow: UIWindow?

    func coverEverything() {
        coveringWindow = UIWindow(frame: (view.window?.frame)!)

        if let coveringWindow = coveringWindow {
            coveringWindow.windowLevel = UIWindowLevelAlert + 1
            coveringWindow.isHidden = false
        }
    }
}

According to the documentation, to receive events that do not have a relevant coordinate value, such as keyboard entry, make it keyinstead of merely !isHidden:

根据文档，要接收没有相关坐标值的事件，例如键盘输入，请使其key而不是仅仅!isHidden：

coveringWindow.makeKeyAndVisible()

You can even control the transparency of its background, for a smoke effect:

您甚至可以控制其背景的透明度，以获得烟雾效果：

coveringWindow.backgroundColor = UIColor(white: 0, alpha: 0.5)

Note that such window needs to handle orientation changes.

请注意，此类窗口需要处理方向更改。

回答by YuLong Xiao

Your window1object is a local variable, when the code runs out of this method, this object does not exist any more. Any UIWindowobject we created will be add to the [[UIApplication sharedApplication] windows], but this array only keep a week reference to any UIWindowobject, so it's up to your own code to keep the window object exist.Why apple achieved like this, I guess, is [UIApplication sharedApplication]object exists as long as the app runs, doing so to avoid keeping the UIWindowobjects which only need to be exist for a while living in the memory "forever".

你的window1对象是一个局部变量，当代码用完这个方法时，这个对象就不再存在了。UIWindow我们创建的任何对象都将被添加到 中[[UIApplication sharedApplication] windows]，但是这个数组只保留对任何UIWindow对象的一周引用，因此保持窗口[UIApplication sharedApplication]对象存在取决于您自己的代码。在应用程序运行时，这样做是为了避免将UIWindow只需要存在一段时间的对象“永远”留在内存中。

What's more, your code could run with MRC.

更重要的是，您的代码可以与 MRC 一起运行。

回答by user6618855

Swift 4

斯威夫特 4

To avoid memory leak, I prefer to initialise my custom window in this way, as proposed by Apple :

为了避免内存泄漏，我更喜欢按照 Apple 的建议以这种方式初始化我的自定义窗口：

If you want to provide a custom window for your app, you must implement the getter method of this property and use it to create and return your custom window.

如果您想为您的应用程序提供自定义窗口，则必须实现此属性的 getter 方法并使用它来创建和返回您的自定义窗口。

Example:

例子：

var myCustomWindow: UIWindow? = CustomWindow(frame: UIScreen.main.bounds)

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

    let mainController: MainViewController = UIStoryboard(name: "Main", bundle: nil).instantiateInitialViewController() as! MainViewController
    self.myCustomWindow?.rootViewController = mainController
    self.myCustomWindow?.makeKeyAndVisible()
}

回答by Mohamed Shaban

if you just need to change shared window ViewController in swift 5

如果您只需要在 swift 5 中更改共享窗口 ViewController

UIApplication.shared.keyWindow?.rootViewController = UINavigationController(rootViewController: yourViewController)

回答by Nirav Gadhiya

try adding a UIViewon mainWindow not another UIWindowlike...

尝试UIView在 mainWindow 上添加一个而不是另一个UIWindow像...

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.window.backgroundColor = [UIColor redColor];
    ViewController *vc = [[ViewController alloc]initWithNibName:@"ViewController" bundle:nil];
    self.window.rootViewController = vc;
    [self.window makeKeyAndVisible];
    UIView * viewAlert = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 320)];
    viewAlert.backgroundColor = [UIColor redColor];
    [self.window.rootViewController.view addSubView:viewAlert];
    /* or you can use following..
    [self.window addSubView:viewAlert];
    */
    [viewAlert release]; //FOR NON ARC
    return YES;
}

回答by Ajith K Jose

In swift a new UIWindowcan be added as follows..

在 swiftUIWindow中可以添加一个新的，如下所示..

class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?
    var viewController: ViewController?
    var navigationController: UINavigationController?

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        self.window = UIWindow(frame: UIScreen.mainScreen().bounds)
        self.viewController = ViewController(nibName: "ViewController", bundle:NSBundle.mainBundle())
        self.navigationController = UINavigationController(rootViewController: self.viewController!)
        self.window!.rootViewController = self.navigationController
        //  self.window!.addSubview(self.viewController!.view)
        self.window!.makeKeyAndVisible()
        return true
    }

    //Other methods..
}