How to download dynamically created file using android webview?

Question

Android

Good afternoon .
I'm trying to make an application on webview android (study). Test server part in php (I use PhpOffice - in response I just send the generated file via $writer->save('php://output'); ), the task is to save it on android using webview . Server logs show that the request is coming - how to save the response on the android side?
Here is the MainActivity.java code:
package com.example.b1;
import androidx.appcompat.app.AppCompatActivity;
import android.annotation.TargetApi;
import android.app.DownloadManager;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.os.environment;
import android.webkit.DownloadListener;
import android.webkit.WebChromeClient;
import android.webkit.WebResourceRequest;
import android.webkit.webview;
import android.webkit.WebViewClient;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
private WebView webView;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
webView = findViewById(R.id.webView);
webView.setWebChromeClient(new WebChromeClient());
webView.setWebViewClient(new MyWebViewClient());
// enable JavaScript support
webView.getSettings().setJavaScriptEnabled(true);
webView.getSettings().setDomStorageEnabled(true);
webView.setVerticalScrollBarEnabled(false);
webView.setHorizontalScrollBarEnabled(false);
//setContentView(webView);
// set the loading page
webView.loadUrl(" 192.168.57.97 ");
webView.setDownloadListener(new DownloadListener() {
@Override
public void onDownloadStart(String url, String userAgent,
String contentDisposition, String mimetype,
long contentLength) {
DownloadManager.Request request = new DownloadManager.Request( Uri.parse(url));
// request.allowScanningByMediaScanner();
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED); //Notify client once download is completed!
// request. setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "Name of your downloadble file goes here, example: Mathematics II ");
DownloadManager dm = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
dm enqueue(request);
Toast.makeText(getApplicationContext(), "Downloading File", //To notify the Client that the file is being downloaded
Toast.LENGTH_LONG).show();
}
});
}
final class JavaScriptInterface {
JavaScriptInterface () { }
public String getSomeString() {
return "string";
}
}
private class MyWebViewClient extends WebViewClient {
@TargetApi(Build.VERSION_CODES.N)
@Override
public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
view.loadUrl(request.getUrl().toString());
return true;
}
// For old devices
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
}
}