问用iframe上传Nativescript Webview中的文件

EN

 let webview: WebView = this.webViewRef.nativeElement;
 let myWebChromeClient: MyWebChromeClient = new MyWebChromeClient();
 webview.android.setWebChromeClient(myWebChromeClient);

import * as imagepicker from "nativescript-imagepicker";
import * as fs from "file-system";

export class MyWebChromeClient extends android.webkit.WebChromeClient {
    file_path:string;
    constructor() {
        super();

        return global.__native(this);
    }

    onShowFileChooser(webView,filePathCallback,fileChooserParams) {

         this.filepathCallback(filePathCallback);

        return true;
    }

    filepathCallback(filePathCallback)
    {
        let context = imagepicker.create({
            mode: "single",
            mediaType: imagepicker.ImagePickerMediaType.Any
        });
       this.startSelection(context,filePathCallback);
    }

    startSelection(context,filePathCallback) {
        context.authorize().then(() => {
                                    return context.present();
                                  })
            .then((selection) => {
                selection.forEach((selected) => {
                    let path = selected.android;
                    let file = fs.File.fromPath(path);
                    this.file_path = file.path;
                    this.file_path = "file://" + this.file_path;
                    let results = Array.create(android.net.Uri, 1);
                    results[0] = android.net.Uri.parse(this.file_path);

                    filePathCallback.onReceiveValue(results);
                    return this.file_path;
                });
            }).catch(function (e) {
                console.log(e);
            });
    }
}