Merge remote-tracking branch 'KiwiStone/issue-3354'

3 files changed, 89 insertions, 2 deletions

diff --git a/main/src/cgeo/geocaching/activity/AbstractViewPagerActivity.java b/main/src/cgeo/geocaching/activity/AbstractViewPagerActivity.java
index 952726e..e6167fb 100644
--- a/main/src/cgeo/geocaching/activity/AbstractViewPagerActivity.java
+++ b/main/src/cgeo/geocaching/activity/AbstractViewPagerActivity.java
@@ -9,6 +9,7 @@ import com.viewpagerindicator.TitleProvider;
 import org.apache.commons.lang3.tuple.Pair;
 
 import android.app.Activity;
+import android.os.Bundle;
 import android.os.Parcelable;
 import android.support.v4.view.PagerAdapter;
 import android.support.v4.view.ViewPager;
@@ -43,6 +44,10 @@ public abstract class AbstractViewPagerActivity<Page extends Enum<Page>> extends
     private final Map<Page, PageViewCreator> viewCreators = new HashMap<Page, PageViewCreator>();
 
     /**
+     * Store the states of the page views to be able to persist them when destroyed and reinstantiated again
+     */
+    private final Map<Page, Bundle> viewStates = new HashMap<Page, Bundle>();
+    /**
      * The {@link ViewPager} for this activity.
      */
     private ViewPager viewPager;
@@ -76,6 +81,16 @@ public abstract class AbstractViewPagerActivity<Page extends Enum<Page>> extends
          * Handles changed data-sets.
          */
         public void notifyDataSetChanged();
+
+        /**
+         * Gets state of the view
+         */
+        public Bundle getViewState();
+
+        /**
+         * Set the state of the view
+         */
+        public void setViewState(Bundle state);
     }
 
     /**
@@ -93,6 +108,14 @@ public abstract class AbstractViewPagerActivity<Page extends Enum<Page>> extends
 
         @Override
         public void destroyItem(ViewGroup container, int position, Object object) {
+
+            final Page page = pageOrder.get(position);
+
+            // Store the state of the view if the page supports it
+            PageViewCreator creator = viewCreators.get(page);
+            Bundle state = creator.getViewState();
+            viewStates.put(page, state);
+
             container.removeView((View) object);
         }
 
@@ -107,6 +130,7 @@ public abstract class AbstractViewPagerActivity<Page extends Enum<Page>> extends
 
         @Override
         public Object instantiateItem(ViewGroup container, int position) {
+
             final Page page = pageOrder.get(position);
 
             PageViewCreator creator = viewCreators.get(page);
@@ -114,6 +138,7 @@ public abstract class AbstractViewPagerActivity<Page extends Enum<Page>> extends
             if (null == creator && null != page) {
                 creator = AbstractViewPagerActivity.this.createViewCreator(page);
                 viewCreators.put(page, creator);
+                viewStates.put(page, new Bundle());
             }
 
             View view = null;
@@ -123,12 +148,16 @@ public abstract class AbstractViewPagerActivity<Page extends Enum<Page>> extends
                     // Result from getView() is maybe cached, but it should be valid because the
                     // creator should be informed about data-changes with notifyDataSetChanged()
                     view = creator.getView();
+
+                    // Restore the state of the view if the page supports it
+                    Bundle state = viewStates.get(page);
+                    creator.setViewState(state);
+
                     container.addView(view, 0);
                 }
             } catch (Exception e) {
                 Log.e("ViewPagerAdapter.instantiateItem ", e);
             }
-
             return view;
         }
 
@@ -225,10 +254,15 @@ public abstract class AbstractViewPagerActivity<Page extends Enum<Page>> extends
     protected abstract String getTitle(Page page);
 
     protected final void reinitializeViewPager() {
+
         // notify all creators that the data has changed
         for (PageViewCreator creator : viewCreators.values()) {
             creator.notifyDataSetChanged();
         }
+        // reset the stored view states of all pages
+        for (Bundle state : viewStates.values()) {
+            state.clear();
+        }
 
         pageOrder.clear();
         final Pair<List<? extends Page>, Integer> pagesAndIndex = getOrderedPages();
diff --git a/main/src/cgeo/geocaching/ui/AbstractCachingPageViewCreator.java b/main/src/cgeo/geocaching/ui/AbstractCachingPageViewCreator.java
index 333ef11..55b153b 100644
--- a/main/src/cgeo/geocaching/ui/AbstractCachingPageViewCreator.java
+++ b/main/src/cgeo/geocaching/ui/AbstractCachingPageViewCreator.java
@@ -2,6 +2,7 @@ package cgeo.geocaching.ui;
 
 import cgeo.geocaching.activity.AbstractViewPagerActivity.PageViewCreator;
 
+import android.os.Bundle;
 import android.view.View;
 
 /**
@@ -29,4 +30,22 @@ public abstract class AbstractCachingPageViewCreator<ViewClass extends View> imp
 
     @Override
     public abstract ViewClass getDispatchedView();
+
+    /**
+     * Gets the state of the view but returns an empty state if not overridden
+     *
+     * @return empty bundle
+     */
+    @Override
+    public Bundle getViewState() {
+        return new Bundle();
+    }
+
+    /**
+     * Restores the state of the view but just returns if not overridden.
+     */
+    @Override
+    public void setViewState(Bundle state) {
+        return;
+    }
 }
diff --git a/main/src/cgeo/geocaching/ui/logs/CacheLogsViewCreator.java b/main/src/cgeo/geocaching/ui/logs/CacheLogsViewCreator.java
index 8fe3866..0a327f3 100644
--- a/main/src/cgeo/geocaching/ui/logs/CacheLogsViewCreator.java
+++ b/main/src/cgeo/geocaching/ui/logs/CacheLogsViewCreator.java
@@ -11,6 +11,7 @@ import cgeo.geocaching.ui.UserActionsClickListener;
 import org.apache.commons.lang3.StringUtils;
 
 import android.content.res.Resources;
+import android.os.Bundle;
 import android.view.View;
 import android.widget.TextView;
 
@@ -109,4 +110,37 @@ public class CacheLogsViewCreator extends LogsViewCreator {
         return new UserActionsClickListener(getCache());
     }
 
-}
\ No newline at end of file
+    /**
+     * Get the state of the current view
+     *
+     * @return the state encapsulated in a bundle
+     */
+    @Override
+    public Bundle getViewState() {
+        if (view == null) {
+            return null;
+        }
+        int position = view.getFirstVisiblePosition();
+        View child = view.getChildAt(0);
+        int positionFromTop = (child == null) ? 0 : child.getTop();
+        Bundle state = new Bundle();
+        state.putInt("position", position);
+        state.putInt("positionFromTop", positionFromTop);
+        return state;
+    }
+
+    /**
+     * Restore a previously stored state of the view
+     *
+     */
+    @Override
+    public void setViewState(Bundle state) {
+        if (view == null) {
+            return;
+        }
+        int logViewPosition = state.getInt("position");
+        int logViewPositionFromTop = state.getInt("positionFromTop");
+        view.setSelectionFromTop(logViewPosition, logViewPositionFromTop);
+        return;
+    }
+}