Fix the ViewPager not always moving to new tabs. https://redmine.stoutner.com/issues/798

[PrivacyBrowserAndroid.git] / app / src / main / java / com / stoutner / privacybrowser / adapters / WebViewPagerAdapter.java

diff --git a/app/src/main/java/com/stoutner/privacybrowser/adapters/WebViewPagerAdapter.java b/app/src/main/java/com/stoutner/privacybrowser/adapters/WebViewPagerAdapter.java
index 510ac7396a1a63a6d813061652274ca696eb706a..52e7234536a22a244cc232b9788112d79c9f7d29 100644 (file)
--- a/app/src/main/java/com/stoutner/privacybrowser/adapters/WebViewPagerAdapter.java
+++ b/app/src/main/java/com/stoutner/privacybrowser/adapters/WebViewPagerAdapter.java
@@ -1,25 +1,27 @@
 /*
- * Copyright © 2019-2020 Soren Stoutner <soren@stoutner.com>.
+ * Copyright © 2019-2022 Soren Stoutner <soren@stoutner.com>.
  *
- * This file is part of Privacy Browser <https://www.stoutner.com/privacy-browser>.
+ * This file is part of Privacy Browser Android <https://www.stoutner.com/privacy-browser-android>.
  *
- * Privacy Browser is free software: you can redistribute it and/or modify
+ * Privacy Browser Android is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 3 of the License, or
  * (at your option) any later version.
  *
- * Privacy Browser is distributed in the hope that it will be useful,
+ * Privacy Browser Android is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with Privacy Browser.  If not, see <http://www.gnu.org/licenses/>.
+ * along with Privacy Browser Android.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 package com.stoutner.privacybrowser.adapters;
 
 import android.os.Bundle;
+import android.os.Handler;
+import android.widget.FrameLayout;
 
 import androidx.annotation.NonNull;
 import androidx.fragment.app.Fragment;
@@ -27,13 +29,15 @@ import androidx.fragment.app.FragmentManager;
 import androidx.fragment.app.FragmentPagerAdapter;
 import androidx.viewpager.widget.ViewPager;
 
+import com.stoutner.privacybrowser.R;
 import com.stoutner.privacybrowser.fragments.WebViewTabFragment;
+import com.stoutner.privacybrowser.views.NestedScrollWebView;
 
 import java.util.LinkedList;
 
 public class WebViewPagerAdapter extends FragmentPagerAdapter {
     // The WebView fragments list contains all the WebViews.
-    private LinkedList<WebViewTabFragment> webViewFragmentsList = new LinkedList<>();
+    private final LinkedList<WebViewTabFragment> webViewFragmentsList = new LinkedList<>();
 
     // Define the constructor.
     public WebViewPagerAdapter(FragmentManager fragmentManager) {
@@ -112,7 +116,7 @@ public class WebViewPagerAdapter extends FragmentPagerAdapter {
 
         // Move to the new page if indicated.
         if (moveToNewPage) {
-            webViewPager.setCurrentItem(pageNumber);
+            moveToNewPage(pageNumber, webViewPager);
         }
     }
 
@@ -125,17 +129,60 @@ public class WebViewPagerAdapter extends FragmentPagerAdapter {
     }
 
     public boolean deletePage(int pageNumber, ViewPager webViewPager) {
+        // Get the WebView tab fragment.
+        WebViewTabFragment webViewTabFragment = webViewFragmentsList.get(pageNumber);
+
+        // Get the WebView frame layout.
+        FrameLayout webViewFrameLayout = (FrameLayout) webViewTabFragment.getView();
+
+        // Remove the warning below that the WebView frame layout might be null.
+        assert webViewFrameLayout != null;
+
+        // Get a handle for the nested scroll WebView.
+        NestedScrollWebView nestedScrollWebView = webViewFrameLayout.findViewById(R.id.nestedscroll_webview);
+
+        // Pause the current WebView.
+        nestedScrollWebView.onPause();
+
+        // Remove all the views from the frame layout.
+        webViewFrameLayout.removeAllViews();
+
+        // Destroy the current WebView.
+        nestedScrollWebView.destroy();
+
         // Delete the page.
         webViewFragmentsList.remove(pageNumber);
 
         // Update the view pager.
         notifyDataSetChanged();
 
-        // Return true if the selected page number did not change after the delete.  This will cause the calling method to reset the current WebView to the new contents of this page number.
+        // Return true if the selected page number did not change after the delete (because the newly selected tab has has same number as the previously deleted tab).
+        // This will cause the calling method to reset the current WebView to the new contents of this page number.
         return (webViewPager.getCurrentItem() == pageNumber);
     }
 
     public WebViewTabFragment getPageFragment(int pageNumber) {
+        // Return the page fragment.
         return webViewFragmentsList.get(pageNumber);
     }
+
+    private void moveToNewPage(int pageNumber, ViewPager webViewPager) {
+        // Check to see if the new page has been populated.
+        if (webViewPager.getChildCount() >= pageNumber) {  // The new page is ready.
+            // Move to the new page.
+            webViewPager.setCurrentItem(pageNumber);
+        } else {  // The new page is not yet ready.
+            // Create a handler.
+            Handler moveToNewPageHandler = new Handler();
+
+            // Create a runnable.
+            Runnable moveToNewPageRunnable = () -> {
+                // Move to the new page.
+                webViewPager.setCurrentItem(pageNumber);
+            };
+
+            // Try again to move to the new page after 50 milliseconds.
+            moveToNewPageHandler.postDelayed(moveToNewPageRunnable, 50);
+        }
+    }
 }
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