refactor: generalize state storing for listview based viewpager pages

4 files changed, 60 insertions, 39 deletions

diff --git a/main/src/cgeo/geocaching/activity/AbstractViewPagerActivity.java b/main/src/cgeo/geocaching/activity/AbstractViewPagerActivity.java
index e6167fb..bb0273f 100644
--- a/main/src/cgeo/geocaching/activity/AbstractViewPagerActivity.java
+++ b/main/src/cgeo/geocaching/activity/AbstractViewPagerActivity.java
@@ -113,8 +113,10 @@ public abstract class AbstractViewPagerActivity<Page extends Enum<Page>> extends
 
             // Store the state of the view if the page supports it
             PageViewCreator creator = viewCreators.get(page);
-            Bundle state = creator.getViewState();
-            viewStates.put(page, state);
+            if (creator != null) {
+                Bundle state = creator.getViewState();
+                viewStates.put(page, state);
+            }
 
             container.removeView((View) object);
         }
diff --git a/main/src/cgeo/geocaching/ui/AbstractCachingListViewPageViewCreator.java b/main/src/cgeo/geocaching/ui/AbstractCachingListViewPageViewCreator.java
new file mode 100644
index 0000000..8588e21
--- /dev/null
+++ b/main/src/cgeo/geocaching/ui/AbstractCachingListViewPageViewCreator.java
@@ -0,0 +1,53 @@
+package cgeo.geocaching.ui;
+
+import cgeo.geocaching.activity.AbstractViewPagerActivity.PageViewCreator;
+
+import android.os.Bundle;
+import android.support.v4.view.ViewPager;
+import android.view.View;
+import android.widget.ListView;
+
+/**
+ * {@link PageViewCreator} for {@link ListView}, which can save scroll state on purging a page from the
+ * {@link ViewPager}, and restore the state on re-recreation.
+ * 
+ */
+public abstract class AbstractCachingListViewPageViewCreator extends AbstractCachingPageViewCreator<ListView> {
+    private static final String STATE_POSITION_FROM_TOP = "positionFromTop";
+    private static final String STATE_POSITION = "position";
+
+    /**
+     * 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(STATE_POSITION, position);
+        state.putInt(STATE_POSITION_FROM_TOP, 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(STATE_POSITION);
+        int logViewPositionFromTop = state.getInt(STATE_POSITION_FROM_TOP);
+        view.setSelectionFromTop(logViewPosition, logViewPositionFromTop);
+        return;
+    }
+
+}
diff --git a/main/src/cgeo/geocaching/ui/logs/CacheLogsViewCreator.java b/main/src/cgeo/geocaching/ui/logs/CacheLogsViewCreator.java
index 0a327f3..6311476 100644
--- a/main/src/cgeo/geocaching/ui/logs/CacheLogsViewCreator.java
+++ b/main/src/cgeo/geocaching/ui/logs/CacheLogsViewCreator.java
@@ -1,17 +1,16 @@
 package cgeo.geocaching.ui.logs;
 
 import cgeo.geocaching.CacheDetailActivity;
+import cgeo.geocaching.CgeoApplication;
 import cgeo.geocaching.Geocache;
 import cgeo.geocaching.LogEntry;
 import cgeo.geocaching.R;
-import cgeo.geocaching.CgeoApplication;
 import cgeo.geocaching.enumerations.LogType;
 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;
 
@@ -110,37 +109,4 @@ public class CacheLogsViewCreator extends LogsViewCreator {
         return new UserActionsClickListener(getCache());
     }
 
-    /**
-     * 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;
-    }
 }
diff --git a/main/src/cgeo/geocaching/ui/logs/LogsViewCreator.java b/main/src/cgeo/geocaching/ui/logs/LogsViewCreator.java
index 15634d3..fb72ee5 100644
--- a/main/src/cgeo/geocaching/ui/logs/LogsViewCreator.java
+++ b/main/src/cgeo/geocaching/ui/logs/LogsViewCreator.java
@@ -8,7 +8,7 @@ import cgeo.geocaching.activity.AbstractActivity;
 import cgeo.geocaching.activity.Progress;
 import cgeo.geocaching.list.StoredList;
 import cgeo.geocaching.network.HtmlImage;
-import cgeo.geocaching.ui.AbstractCachingPageViewCreator;
+import cgeo.geocaching.ui.AbstractCachingListViewPageViewCreator;
 import cgeo.geocaching.ui.AnchorAwareLinkMovementMethod;
 import cgeo.geocaching.ui.DecryptTextClickListener;
 import cgeo.geocaching.ui.Formatter;
@@ -30,7 +30,7 @@ import android.widget.TextView;
 import java.util.ArrayList;
 import java.util.List;
 
-public abstract class LogsViewCreator extends AbstractCachingPageViewCreator<ListView> {
+public abstract class LogsViewCreator extends AbstractCachingListViewPageViewCreator {
 
     protected final AbstractActivity activity;