XMLHttpRequest dosen't throw error but onload isn't called

Issue

I'm making an android app so that I can edit values on my server from my phone but when I try to send a get request to get the initial values I don't get any response.

I use android web view to be able to use javascript as I do not know java

It works when running it outside android (on an express server) so i suspect it has something to do with android web view

The MainActivity.java

public class MainActivity extends AppCompatActivity {

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

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

        WebSettings webSetting = WebViewWithCSS.getSettings();
        webSetting.setJavaScriptEnabled(true);

        WebViewWithCSS.setWebViewClient(new WebViewClient());
        WebViewWithCSS.loadUrl("file:///android_asset/www/index.html");
    }

    private class WebViewClient extends android.webkit.WebViewClient
    {
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url)
        {
            return super.shouldOverrideUrlLoading(view, url);
        }
    }
}

The javascript file

  var getJSON = function(url, callback) {
      var xhr = new XMLHttpRequest();
      xhr.open('GET', url, true);
      xhr.responseType = 'json';
      xhr.onload = function() {
        var status = xhr.status;
        if (status === 200) {
          callback(null, xhr.response);
        } else {
          callback(status, xhr.response);
        }
      };
      xhr.send()
  };

  getJSON('http://totalytherealdeal.url/get', function(err, data) {
    console.log(data)
    if (err !== null) {
      console.log(err)
    } else {
      console.log(data)
    }
  });

As I said it doesn't output any unexpected code in the debugger. It seems like something goes wrong when it tries xhr.send() as it doesn't run anyting afterwards inside xhr.onload or logs the data

English isn't my first language

Solution

Make sure you have permissions in your manifest:

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />

Also a note that for the protection of its users Android won't process an HTTP request to any server that doesn't have a valid SSL certificate.

Answered By - vasmos