如何在Xamarin表单中加载PDF [英] How to load PDF in Xamarin Forms

问题描述

我有一个Xamarin Forms应用程序，我想在其中打开本地存储的PDF.我不需要将它们加载到应用程序中，可以使用设备的默认PDF查看器浏览器.我该怎么办?

I have a Xamarin Forms app where I want to open a locally stored PDF. I don't need to load them within the app, I'm fine with shelling out to the device's default document viewer for PDFs. How can I do this?

我尝试将WebView发送到PDF，但这没有用，我只有一个空白页.

I tried sending a WebView to the PDF, but that didn't work, I just got a blank page.

推荐答案

我最近在我自己的项目中使用自定义渲染器进行了此操作.首先实现一个空的Xamarin表单视图，例如(我已经包含了一个可绑定的FilePath属性):

I've recently done this in my own project using a custom renderer. First implement an empty Xamarin forms view such as (I've included a bindable FilePath attribute):

    public class PdfViewer : View
{
    public static readonly BindableProperty FilePathProperty =
        BindableProperty.Create<DocumentViewer, string>(p => p.FilePath, null);

    public string FilePath
    {
        get
        {
            return (string)this.GetValue(FilePathProperty);
        }

        set
        {
            this.SetValue(FilePathProperty, value);
        }
    }
}

然后创建将为此控件注册的iOS渲染器.该渲染器可以在iOS项目中使用委派给内置的iOS pdf查看器:

Then create an iOS Renderer that will be registered for this control. This renderer can, as it is within an iOS project, use the Quick Look Preview Controller to delegate to the built in iOS pdf viewer:

[assembly: ExportRenderer(typeof(PdfViewer), typeof(DocumentViewRenderer))]

public class DocumentViewRenderer 
        : ViewRenderer<PdfViewer, UIView>
{
    private QLPreviewController controller;

    protected override void OnElementChanged(ElementChangedEventArgs<DocumentViewer> e)
    {
        base.OnElementChanged(e);

        this.controller = new QLPreviewController();
        this.controller.DataSource = new DocumentQLPreviewControllerDataSource(e.NewElement.FilePath);

        SetNativeControl(this.controller.View);
    }

    private class DocumentQLPreviewControllerDataSource : QLPreviewControllerDataSource 
    {
        private string fileName;
        public DocumentQLPreviewControllerDataSource(string fileName)
        {
            this.fileName = fileName;
        }

        public override int PreviewItemCount(QLPreviewController controller) 
        {
            return 1;
        }

        public override QLPreviewItem GetPreviewItem(QLPreviewController controller, int index)
        {
            var documents = NSBundle.MainBundle.BundlePath;
            var library = Path.Combine(documents, this.fileName);
            NSUrl url = NSUrl.FromFilename(library);

            return new QlItem(string.Empty, url);
        }

        private class QlItem : QLPreviewItem 
        { 
            public QlItem(string title, NSUrl uri) 
            { 
                this.ItemTitle = title; 
                this.ItemUrl = uri; 
            } 

            public override string ItemTitle { get; private set; }

            public override NSUrl ItemUrl { get; private set; }
        }
    }
}

当我从较大的项目中提取它时，我还没有编译并运行它，但是总的来说这应该可以工作.

I haven't compiled and run this as I've extracted it from my larger project but in general this should work.

这篇关于如何在Xamarin表单中加载PDF的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！