Android Webview将pdf，xlsm下载为html文件

Question

我将自己的网站转换为android webview应用。一切正常，但是当我尝试从我的网站下载任何文件时，文件正在以HTML格式下载。但是，当我尝试从PC或移动浏览器下载文件时，文件的下载格式正确。

webView.setDownloadListener(new DownloadListener() {
        @Override
        public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype, long contentLength) {
            DownloadManager.Request myRequest = new DownloadManager.Request(Uri.parse(url));
            myRequest.allowScanningByMediaScanner();
            myRequest.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);

            DownloadManager myManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
            Objects.requireNonNull(myManager).enqueue(myRequest);
            Toast.makeText(MainActivity.this,"Download Started....", Toast.LENGTH_SHORT).show();
        }
    }