Open Android app with Webview by pressing deeplink URL from notifications

Background: * Full Stack developer training (recently finished studies). * Am not very (putting it mildly) Java savvy.

for the past couple of days I've been trying to make the tapping on a OneSignal notification open the app according to the URL stored in the notification payload.

What did work was: * If the app is showing on the screen and you press the notification it works fine and opens it accordingly.

It does ALMOST work in the way that if the app is in the background and you press the notification it either: 1. Launches the app but on the main page OR 2. Doesn't launch the app but when you actively go back to the app it shows the correct content (according to the URL of the notification)

Following is the code:

Thank you!

package app.web.hodaya;

import com.onesignal.OSNotificationOpenResult;
import com.onesignal.OneSignal;


import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.webkit.JavascriptInterface;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;

import org.json.JSONObject;

import static com.onesignal.OneSignal.sendTag;

import static com.onesignal.OneSignal.sendTags;

public class MainActivity extends AppCompatActivity {

    private WebView webView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            WebView.setWebContentsDebuggingEnabled(true);
        }

        CalculateObject calcObject = new CalculateObject();
        PassingStringThrough passString = new PassingStringThrough();
        ExampleNotificationOpenedHandler notificationOpened = new ExampleNotificationOpenedHandler();
        UpdateOneSignalSettingTags sendTag = new UpdateOneSignalSettingTags();
        super.onCreate(savedInstanceState);


        // OneSignal Initialization
        OneSignal.startInit(this)
                .inFocusDisplaying(OneSignal.OSInFocusDisplayOption.Notification)
                .unsubscribeWhenNotificationsAreDisabled(true)
                .setNotificationOpenedHandler(new ExampleNotificationOpenedHandler())
                .init();


        setContentView(R.layout.activity_main);

        webView = findViewById(R.id.webView);
        webView.setWebViewClient(new WebViewClient());
        webView.loadUrl("https://hodaya-app.firebaseapp.com/");
        WebSettings webSettings = webView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        webView.getSettings().setDomStorageEnabled(true);
        webView.addJavascriptInterface(passString, "ob1");


        try {
            this.getSupportActionBar().hide();
        } catch (NullPointerException e) {
        }

    }

    @Override
    public void onBackPressed() {
        if (webView.canGoBack()) {
            webView.goBack();
        } else {
            super.onBackPressed();
        }
    }



    class PassingStringThrough {
        @JavascriptInterface
        public void passString(
                String m, String m1, String n, String n1, String e, String e1,
                String name, String name1, String gender, String gender1) {
            sendTag(m, m1);
            sendTag(n, n1);
            sendTag(e, e1);
            sendTag(name, name1);
            sendTag(gender, gender1);

            /* alternatively*/
//            tags.put(m, m1);
//            tags.put(n, n1);
//            tags.put(e, e1);
//            OneSignal.sendTags(tags);

            Log.d("settingsPassedCorrectly", "I just got executed!" + m + m1 + n + n1 + e + e1 + name + name1 + gender + gender1);
        }
    }
    class ExampleNotificationOpenedHandler implements OneSignal.NotificationOpenedHandler {
        @Override
        public void notificationOpened(OSNotificationOpenResult result) {
            Log.i("OSNotificationPayload", "result.notification.payload.toJSONObject().toString(): " + result.notification.payload.toJSONObject().toString());

            JSONObject data = result.notification.payload.additionalData;
            String customKey;
            if (data != null) {
                customKey = data.optString("tryli", null);
//                if (customKey != null)
                Log.i("DeepLinkToCustomkey", "customkey set with value: " + customKey);


                WebView webView1;
//                setContentView(R.layout.activity_main);
                webView1 = findViewById(R.id.webView);
                webView1.setWebViewClient(new WebViewClient());
                webView1.loadUrl(customKey);

//                WebView webView = null;

}