为什么我的下载链接在 Android WebView 中不起作用？

Question

在我的 Angular 2 应用程序中，用户可以单击文件进行下载。这将从经过身份验证的 Web 服务调用中获取链接，并将其下载到浏览器中。

在浏览器（PC、Android 上的 Chrome 等）上一切正常。

它在带有 WebView 的混合 Android 应用程序中不起作用，尽管我认为我做了任何需要的事情。似乎从来没有为生成的链接调用 WebViewClient::onLoadResource 。

这是我的 angular 2 组件中的相关部分：

onPathClicked(path:Path) {
    if (path.directory) {
        var newPathEntries = this.appendToPath(this.pathEntries, path.fileName);
        this.searchContents(newPathEntries);
    } else {
        var fileName = path.fileName;
        var pathEntries = this.pathEntries.push(fileName);
        var fullPath = this.buildFullPath(pathEntries);
        this.fileService.getFileDownloadUrl(fullPath)
            .then((url)=> {
                var fileInput:HTMLAnchorElement = <HTMLAnchorElement>document.getElementById('downloadFileLink');
                fileInput.href = url;
                fileInput.setAttribute('download', path.fileName);
                fileInput.click();
            })
            .catch((error)=> {
                this.errorService.showError('Impossible de télécharger le fichier', error);
            });
    }
}

这里是安卓部分：

import android.app.Activity;
import android.app.AlertDialog;
import android.app.DownloadManager;
import android.app.DownloadManager.Request;
import android.content.DialogInterface;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.view.Menu;
import android.view.MenuInflater;
import android.webkit.DownloadListener;
import android.webkit.WebChromeClient;
import android.webkit.WebResourceError;
import android.webkit.WebResourceRequest;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;

public class BlablaActivity extends Activity {

    private WebView webView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_xyz_mobile);

        webView = (WebView) findViewById(R.id.webView);

        WebSettings webSettings = webView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        webSettings.setDomStorageEnabled(true);
        webSettings.setDatabaseEnabled(true);

        WebChromeClient webChromeClient = new WebChromeClient() {
        };
        webView.setWebChromeClient(webChromeClient);

        final DownloadListener downloadListener = new DownloadListener() {
            public void onDownloadStart(String url, String userAgent,
                                        String contentDisposition, String mimetype,
                                        long contentLength) {
                Request request = new Request(Uri.parse(url));
                request.allowScanningByMediaScanner();
                request.setNotificationVisibility(Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
                request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "download");

                DownloadManager downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
                downloadManager.enqueue(request);

                Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT); //This is important!
                intent.addCategory(Intent.CATEGORY_OPENABLE); //CATEGORY.OPENABLE
                intent.setType("*/*");//any application,any extension
                Toast.makeText(getApplicationContext(), "Téléchargement", //To notify the Client that the file is being downloaded
                        Toast.LENGTH_LONG).show();
            }
        };
        webView.setDownloadListener(downloadListener);

        WebViewClient webViewClient = new WebViewClient() {
            @Override
            public void onPageStarted(WebView view, String url, Bitmap favicon) {
                super.onPageStarted(view, url, favicon);
            }

            @Override
            public void onLoadResource(WebView view, String url) {
                super.onLoadResource(view, url);
            }

            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                view.loadUrl(url);
                webView.setDownloadListener(downloadListener);
                return true;
            }

            @Override
            public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) {
//                view.loadUrl("file:///android_asset/load_error.html");
//                view.loadData("Erreur : " + error + ". Veuillez vous connecter pour utiliser l'application.", "text/plain", "utf-8");
                showDefaultError();
            }
        };
        webView.setWebViewClient(webViewClient);

        loadJsApp();
    }

    private void loadJsApp() {
        webView.loadUrl("https://www.mymobileapp.com");
    }

    private void showDefaultError() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Erreur");
        builder.setMessage("Désolé, une erreur s'est produite. Veuillez vérifier votre connexion Internet.");

        builder.setIcon(android.R.drawable.ic_dialog_alert);

        AlertDialog dialog = builder.create();
        builder.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
                loadJsApp();
            }
        });

        dialog.show();

        //Toast.makeText(this, "Réseau indisponible !", Toast.LENGTH_LONG).show();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        MenuInflater menuInflater = getMenuInflater();
        menuInflater.inflate(R.menu.menu_xyz_mobile, menu);
        return true;
    }

}

Answer 1

奇怪的是，在 Android WebView 中似乎没有正确处理 HTML 锚元素上的“下载”属性。 删除该属性应该会按预期触发文件下载。