Go page back in webview instead closing app (#7)

Author: divadsn

app/src/main/java/de/codebucket/mkkm/KKMWebviewClient.java

@@ -4,17 +4,20 @@
 import android.content.res.AssetManager;
 import android.graphics.Bitmap;
 import android.util.Log;
+import android.view.MenuItem;
 import android.webkit.JavascriptInterface;
 import android.webkit.WebView;
 import android.webkit.WebViewClient;
 
-import com.google.android.material.navigation.NavigationView;
-
 import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
 
+import com.google.android.material.navigation.NavigationView;
+
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.HashMap;
+import java.util.Map;
 
 import de.codebucket.mkkm.ui.MainActivity;
 
@@ -28,6 +31,17 @@ public class KKMWebviewClient extends WebViewClient {
     private NavigationView mNavigationView;
 
     private boolean hasInjected = false;
+    private Map<String, Integer> navIds = new HashMap<String, Integer>(){{
+        // R.id.nav_tickets
+        put("home", R.id.nav_tickets);
+        put("control", R.id.nav_tickets);
+
+        // R.id.nav_purchase
+        put("ticket", R.id.nav_purchase);
+
+        // R.id.nav_account
+        put("account", R.id.nav_account);
+    }};
 
     public KKMWebviewClient(MainActivity context) {
         mContext = context;
@@ -40,6 +54,11 @@ public void onPageStarted(WebView view, String url, Bitmap favicon) {
         super.onPageStarted(view, url, favicon);
         mSwipeLayout.setEnabled(true);
         mSwipeLayout.setRefreshing(true);
+
+        // Reset injection if url is webapp
+        if (url.startsWith(WEBAPP_URL)) {
+            hasInjected = false;
+        }
     }
 
     @Override
@@ -75,6 +94,16 @@ public void onPageFinished(WebView view, String url) {
             view.addJavascriptInterface(new ScriptInjectorCallback(), "ScriptInjector");
             view.evaluateJavascript(inject, null);
         }
+
+        // Set navigation item if page has changed
+        String key = url.substring(WEBAPP_URL.length() + 4).split("/")[0];
+        if (navIds.containsKey(key)) {
+            MenuItem item = mNavigationView.getMenu().findItem(navIds.get(key));
+            if (item != null && !item.isChecked()) {
+                ((MainActivity) mContext).setTitle(item.getTitle());
+                mNavigationView.setCheckedItem(item);
+            }
+        }
     }
 
     public static String getPageUrl(String page) {

app/src/main/java/de/codebucket/mkkm/ui/MainActivity.java

@@ -123,6 +123,11 @@ public void onBackPressed() {
             return;
         }
 
+        if (mWebview.canGoBack()) {
+            mWebview.goBack();
+            return;
+        }
+
         if (mBackPressed + TIME_INTERVAL < System.currentTimeMillis()) {
             Toast.makeText(this, R.string.press_back_again, Toast.LENGTH_SHORT).show();
             mBackPressed = System.currentTimeMillis();