从QLPreviewController中删除不需要的顶部空间
从QLPreviewController中删除不需要的顶部空间
提问于 2019-06-11 16:49:42
在我的应用程序中，我使用QLPreviewController来显示一些pdf文件。一切都很好，但是QLPreviewController的内容顶部有一个不需要的空间，无法找到删除它的方法。
我就是这么写的。(请注意，我是Xamarin.iOS和QLPreviewController的新手)
public partial class ReportsViewController : UIViewController
{
public override void ViewDidLoad()
{
base.ViewDidLoad();
//Customize navigation bar for QLPreviewController
if(UIDevice.CurrentDevice.CheckSystemVersion(11, 0)) // There is a bug with barTintColor on QLPreviewController for iOS 11 if you are showing it via presentViewController: animated:
{
var color = UIColor.FromRGB(red: 23, green: 61, blue: 86).CGColor;
var rect = new CGRect(x: 0.0, y: 0.0, width: 1.0, height: 1.0);
var alpha = color.Alpha;
var opaque = alpha == 1;
UIGraphics.BeginImageContextWithOptions(rect.Size, opaque, 0);
var context = UIGraphics.GetCurrentContext();
context.SetFillColor(color);
context.FillRect(rect);
var image = UIGraphics.GetImageFromCurrentImageContext();
UIGraphics.EndImageContext();
UINavigationBar.AppearanceWhenContainedIn(typeof(QLPreviewController)).SetBackgroundImage(image, UIBarMetrics.Default);
}
else // If iOS version is below 11.0
{
UINavigationBar.AppearanceWhenContainedIn(typeof(QLPreviewController)).BarTintColor = UIColor.FromRGBA(red: 255, green: 0, blue: 0, alpha: 1.0f);
}
UINavigationBar.AppearanceWhenContainedIn(typeof(QLPreviewController)).BarStyle = UIBarStyle.Black;
UINavigationBar.AppearanceWhenContainedIn(typeof(QLPreviewController)).TintColor = UIColor.White;
var reportSavedPath = "path to pdf file";
var reportName = "Report name";
var previewController = new QLPreviewController();
var url = new NSUrl(reportSavedPath, true);
var _dataSource = new PreviewControllerSource(this, url, reportName);
previewController.DataSource = _dataSource;
PresentViewController(previewController, true, completionHandler: null);
}
}
public partial class ReportsViewController : UIViewController
{
class PreviewControllerSource : QLPreviewControllerDataSource
{
ReportsViewController _parentClass = null;
NSUrl _url = null;
string _title = null;
public PreviewControllerSource(ReportsViewController parentClass, NSUrl url, string title)
{
_parentClass = parentClass;
_url = url;
_title = title;
}
public override nint PreviewItemCount(QLPreviewController controller)
{
return 1;
}
public override IQLPreviewItem GetPreviewItem(QLPreviewController controller, nint index)
{
return new PreviewItem { title = _title, url = _url };
}
}
public class PreviewItem : QLPreviewItem
{
public string title { get; set; }
public NSUrl url { get; set; }
public override string ItemTitle { get { return title; } }
public override NSUrl ItemUrl { get { return url; } }
}
}--这就是当pdf被加载时的样子，
有人能帮我把这个多余的空间移走吗？
回答 1
Stack Overflow用户
发布于 2019-06-12 02:58:41
不知道为什么要在代码中使用Customize navigation bar for QLPreviewController。我把它拿掉了，效果很好。
我想给你两种方法来摆脱那些不想要的笨蛋：
1.删除守则：
//UINavigationBar.AppearanceWhenContainedIn(typeof(QLPreviewController)).SetBackgroundImage(image, UIBarMetrics.Default);2.如果您确实需要代码来自定义导航栏，请在PresentViewController之前添加这一行代码
//Add this line before PresentViewController
UINavigationBar.AppearanceWhenContainedIn(typeof(QLPreviewController)).SetBackgroundImage(null, UIBarMetrics.Default);
PresentViewController(previewController, true, completionHandler: null);更新：
花了整个下午，只找到了一个不太完美的解决方案。首先，我想说，navigationBar of your viewController和navigationBar of QLPreviewController是两个不同的酒吧。
若要设置导航栏颜色，只需在AppDelegate中设置它，这将影响项目中的整个navigationBar颜色。
public override bool FinishedLaunching(UIApplication application, NSDictionary launchOptions)
{
// Override point for customization after application launch.
// If not required for your application you can safely delete this method
UINavigationBar.Appearance.BarTintColor = UIColor.FromRGBA(red: 255, green: 0, blue: 0, alpha: 1.0f);
UINavigationBar.Appearance.BarStyle = UIBarStyle.BlackOpaque;
UINavigationBar.Appearance.TintColor = UIColor.White;
return true;
}要更改navigationbarColor of QLPreviewControl，可以使用test函数中的代码：
public partial class ViewController : UIViewController
{
QLPreviewController previewController;
public ViewController(IntPtr handle) : base(handle)
{
}
public override void ViewDidLoad()
{
base.ViewDidLoad();
this.AutomaticallyAdjustsScrollViewInsets = false;
this.ExtendedLayoutIncludesOpaqueBars = false;
this.EdgesForExtendedLayout = UIRectEdge.None;
string path = NSBundle.MainBundle.PathForResource("myPdf.pdf","");
var reportName = "Report name";
previewController = new QLPreviewController();
var url = new NSUrl(path, true);
var _dataSource = new PreviewControllerSource(this, url, reportName);
previewController.DataSource = _dataSource;
this.NavigationController.PresentViewController(previewController, true, test);
}
public void test() {
var firstChild = previewController.ChildViewControllers[0];
if (firstChild is UINavigationController)
{
var naviVc = firstChild as UINavigationController;
naviVc.NavigationBar.BarTintColor = UIColor.Red ;
}
}
}唯一不太完美的是，test函数将调用，直到呈现完成，因此您将看到navigationBar的默认颜色，然后它将更改为您想要的颜色。
如果使用推送操作而不是模式，则可以在test中调用WillShowViewController(UINavigationController navigationController, [Transient] UIViewController viewController, bool animated)函数。
public class naviDeleagte : UINavigationControllerDelegate {
public override void WillShowViewController(UINavigationController navigationController, [Transient] UIViewController viewController, bool animated)
{
//call test here if you use a push instead of modal
}
}我把我的样本上传到这里，你可以查看它：navigationBar-color-xamarin.forms
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/56548405
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