如何在swift中居中popoverview [英] how to center a popoverview in swift

问题描述

我有以下代码来显示没有箭头的popoverview（对话框），它可以正常工作。唯一的问题是，对话框显示在左上角（IPad）。我想将视图集中在屏幕上。

I have the following code to show a popoverview (dialog) without an arrow, which works fine. The only problem is, that the dialog is shown in the top left (IPad). I would like to center the view on the screen.

在我的下面的代码中要更改或添加什么？ ：

What to change or add in my following code ? :

func show_help(){


    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    let controller = storyboard.instantiateViewControllerWithIdentifier("Help") as! UIViewController

    controller.modalPresentationStyle = UIModalPresentationStyle.Popover

    let popoverPresentationController = controller.popoverPresentationController

    // result is an optional (but should not be nil if modalPresentationStyle is popover)
    if let _popoverPresentationController = popoverPresentationController {

        // set the view from which to pop up
        _popoverPresentationController.sourceView = self.view;
        _popoverPresentationController.permittedArrowDirections = UIPopoverArrowDirection.allZeros;
        // present (id iPhone it is a modal automatic full screen)
        self.presentViewController(controller, animated: true, completion: nil)
    }

}

其他信息

在我的视图中，链接到我的viewcontroller我设置了这样的优先大小：

In my view, which is linked to my viewcontroller I set the preffered size like this:

override func viewDidLoad() {
        let dialogheigth:CGFloat = self.view.frame.height * 0.5;
        let dialogwidth:CGFloat = self.view.frame.width * 0.5;
        self.preferredContentSize = CGSizeMake(dialogwidth,dialogheigth);
}

推荐答案

您需要提供来源用于弹出的矩形。

You need to provide the source rect for the popover.

从苹果文档：源矩形是指定视图中用于锚定弹出窗口的矩形。将此属性与sourceView属性一起使用以指定弹出窗口的锚点位置。

在您的情况下，在

_popoverPresentationController.sourceView = self.view;

add：

_popoverPresentationController.sourceRect = CGRectMake(CGRectGetMidX(self.view.bounds), CGRectGetMidY(self.view.bounds),0,0)

它会起作用！

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