Fixes for screen orientation changes

core/src/main/java/org/lucasr/twowayview/TwoWayLayoutManager.java

@@ -49,6 +49,8 @@ public static enum Direction {
         END
     }
 
+    private int mScreenOrientation;
+
     private RecyclerView mRecyclerView;
 
     private boolean mIsVertical = true;
@@ -63,9 +65,13 @@ public static enum Direction {
 
     public TwoWayLayoutManager(Context context, AttributeSet attrs) {
         this(context, attrs, 0);
+        this.mScreenOrientation = context.getResources().getConfiguration().orientation;
     }
 
     public TwoWayLayoutManager(Context context, AttributeSet attrs, int defStyle) {
+
+        this.mScreenOrientation = context.getResources().getConfiguration().orientation;
+
         final TypedArray a =
                 context.obtainStyledAttributes(attrs, R.styleable.twowayview_TwoWayLayoutManager, defStyle, 0);
 
@@ -88,6 +94,14 @@ public TwoWayLayoutManager(Orientation orientation) {
         mIsVertical = (orientation == Orientation.VERTICAL);
     }
 
+    public void setScreenOrientation(int orientation) {
+        this.mScreenOrientation = orientation;
+    }
+
+    public int getScreenOrientation() {
+        return mScreenOrientation;
+    }
+
     private int getTotalSpace() {
         if (mIsVertical) {
             return getHeight() - getPaddingBottom() - getPaddingTop();

layouts/src/main/java/org/lucasr/twowayview/widget/BaseLayoutManager.java

@@ -21,7 +21,6 @@
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.support.v7.widget.RecyclerView;
-import android.support.v7.widget.RecyclerView.Adapter;
 import android.support.v7.widget.RecyclerView.LayoutParams;
 import android.support.v7.widget.RecyclerView.Recycler;
 import android.support.v7.widget.RecyclerView.State;
@@ -36,6 +35,7 @@
 import static org.lucasr.twowayview.widget.Lanes.calculateLaneSize;
 
 public abstract class BaseLayoutManager extends TwoWayLayoutManager {
+
     private static final String LOGTAG = "BaseLayoutManager";
 
     protected static class ItemEntry implements Parcelable {
@@ -195,6 +195,11 @@ void getDecoratedChildFrame(View child, Rect childFrame) {
         childFrame.bottom = getDecoratedBottom(child);
     }
 
+    @Override
+    public void setScreenOrientation(int orientation) {
+        super.setScreenOrientation(orientation);
+    }
+
     boolean isVertical() {
         return (getOrientation() == Orientation.VERTICAL);
     }
@@ -217,6 +222,8 @@ void clearItemEntries() {
         if (mItemEntries != null) {
             mItemEntries.clear();
         }
+        invalidateItemLanesAfter(0);
+        ensureLayoutState();
     }
 
     void invalidateItemLanesAfter(int position) {
@@ -334,8 +341,11 @@ public void offsetChildrenVertical(int offset) {
 
     @Override
     public void onLayoutChildren(Recycler recycler, State state) {
+
         final boolean restoringLanes = (mLanesToRestore != null);
+
         if (restoringLanes) {
+
             mLanes = mLanesToRestore;
             mItemEntries = mItemEntriesToRestore;
 
@@ -353,10 +363,6 @@ public void onLayoutChildren(Recycler recycler, State state) {
 
         final int itemCount = state.getItemCount();
 
-        if (mItemEntries != null) {
-            mItemEntries.setAdapterSize(itemCount);
-        }
-
         final int anchorItemPosition = getAnchorItemPosition(state);
 
         // Only move layout if we're not restoring a layout state.
@@ -419,6 +425,7 @@ public Parcelable onSaveInstanceState() {
             state.lanes[i] = laneRect;
         }
 
+        state.screenOrientation = getScreenOrientation();
         state.orientation = getOrientation();
         state.laneSize = (mLanes != null ? mLanes.getLaneSize() : 0);
         state.itemEntries = mItemEntries;
@@ -430,9 +437,14 @@ public Parcelable onSaveInstanceState() {
     public void onRestoreInstanceState(Parcelable state) {
         final LanedSavedState ss = (LanedSavedState) state;
 
-        if (ss.lanes != null && ss.laneSize > 0) {
+        if (ss.lanes != null && ss.laneSize > 0 && ss.screenOrientation == getScreenOrientation()) {
             mLanesToRestore = new Lanes(this, ss.orientation, ss.lanes, ss.laneSize);
             mItemEntriesToRestore = ss.itemEntries;
+        } else {
+            if(mItemEntries!=null) {
+                mItemEntries.clear();
+            }
+            invalidateItemLanesAfter(0);
         }
 
         super.onRestoreInstanceState(ss.getSuperState());
@@ -567,6 +579,7 @@ public LayoutParams generateLayoutParams(Context c, AttributeSet attrs) {
     abstract void moveLayoutToPosition(int position, int offset, Recycler recycler, State state);
 
     protected static class LanedSavedState extends SavedState {
+        private int screenOrientation;
         private Orientation orientation;
         private Rect[] lanes;
         private int laneSize;
@@ -579,6 +592,7 @@ protected LanedSavedState(Parcelable superState) {
         private LanedSavedState(Parcel in) {
             super(in);
 
+            screenOrientation = in.readInt();
             orientation = Orientation.values()[in.readInt()];
             laneSize = in.readInt();
 
@@ -606,6 +620,7 @@ private LanedSavedState(Parcel in) {
         public void writeToParcel(Parcel out, int flags) {
             super.writeToParcel(out, flags);
 
+            out.writeInt(screenOrientation);
             out.writeInt(orientation.ordinal());
             out.writeInt(laneSize);
 
@@ -637,4 +652,6 @@ public LanedSavedState[] newArray(int size) {
             }
         };
     }
+
+
 }

layouts/src/main/java/org/lucasr/twowayview/widget/ItemEntries.java

@@ -22,112 +22,83 @@
 package org.lucasr.twowayview.widget;
 
 import android.util.Log;
+import android.util.SparseArray;
 
 import java.util.Arrays;
 
 import org.lucasr.twowayview.widget.BaseLayoutManager.ItemEntry;
 
 class ItemEntries {
-    private static final int MIN_SIZE = 10;
 
-    private ItemEntry[] mItemEntries;
-    private int mAdapterSize;
-    private boolean mRestoringItem;
-
-    private int sizeForPosition(int position) {
-        int len = mItemEntries.length;
-        while (len <= position) {
-            len *= 2;
-        }
-
-        // We don't apply any constraints while restoring
-        // item entries.
-        if (!mRestoringItem && len > mAdapterSize) {
-            len = mAdapterSize;
-        }
-
-        return len;
-    }
-
-    private void ensureSize(int position) {
-        if (mItemEntries == null) {
-            mItemEntries = new ItemEntry[Math.max(position, MIN_SIZE) + 1];
-            Arrays.fill(mItemEntries, null);
-        } else if (position >= mItemEntries.length) {
-            ItemEntry[] oldItemEntries = mItemEntries;
-            mItemEntries = new ItemEntry[sizeForPosition(position)];
-            System.arraycopy(oldItemEntries, 0, mItemEntries, 0, oldItemEntries.length);
-            Arrays.fill(mItemEntries, oldItemEntries.length, mItemEntries.length, null);
-        }
-    }
+    private SparseArray<ItemEntry> mItemEntries = new SparseArray<ItemEntry>();
 
     public ItemEntry getItemEntry(int position) {
-        if (mItemEntries == null || position >= mItemEntries.length) {
-            return null;
-        }
-
-        return mItemEntries[position];
+        return mItemEntries.get(position);
     }
 
     public void putItemEntry(int position, ItemEntry entry) {
-        ensureSize(position);
-        mItemEntries[position] = entry;
+        mItemEntries.put(position,entry);
     }
 
     public void restoreItemEntry(int position, ItemEntry entry) {
-        mRestoringItem = true;
         putItemEntry(position, entry);
-        mRestoringItem = false;
     }
 
-    public int size() {
-        return (mItemEntries != null ? mItemEntries.length : 0);
-    }
 
-    public void setAdapterSize(int adapterSize) {
-        mAdapterSize = adapterSize;
+    /**
+     * From android.util.SparseArray:
+     *
+     * The keys corresponding to indices in ascending order are guaranteed to be in ascending
+     * order, e.g., keyAt(0) will return the smallest key and keyAt(size()-1) will return the
+     * largest key.
+     */
+
+    public int size() {
+        return (mItemEntries.size()==0 ? 0 : mItemEntries.keyAt(mItemEntries.size()-1));
     }
 
     public void invalidateItemLanesAfter(int position) {
-        if (mItemEntries == null || position >= mItemEntries.length) {
+        if (mItemEntries.size()==0 || position > mItemEntries.keyAt(mItemEntries.size()-1)) {
             return;
         }
 
-        for (int i = position; i < mItemEntries.length; i++) {
-            final ItemEntry entry = mItemEntries[i];
-            if (entry != null) {
-                entry.invalidateLane();
-            }
+        for (int i = position; i < mItemEntries.size(); i++) {
+            final ItemEntry entry = mItemEntries.valueAt(i);
+            entry.invalidateLane();
         }
     }
 
     public void clear() {
-        if (mItemEntries != null) {
-            Arrays.fill(mItemEntries, null);
-        }
+        mItemEntries.clear();
     }
 
     void offsetForRemoval(int positionStart, int itemCount) {
-        if (mItemEntries == null || positionStart >= mItemEntries.length) {
-            return;
-        }
 
-        ensureSize(positionStart + itemCount);
+        for(int n = 0; n < (mItemEntries.size() - positionStart - itemCount); n++) {
+
+            int actualPosition = positionStart+itemCount+n;
+            int movedPosition = positionStart+n;
+
+            ItemEntry temp = mItemEntries.get(actualPosition);
+            mItemEntries.remove(actualPosition);
+            mItemEntries.put(movedPosition, temp);
+
+        }
 
-        System.arraycopy(mItemEntries, positionStart + itemCount, mItemEntries, positionStart,
-                mItemEntries.length - positionStart - itemCount);
-        Arrays.fill(mItemEntries, mItemEntries.length - itemCount, mItemEntries.length, null);
     }
 
     void offsetForAddition(int positionStart, int itemCount) {
-        if (mItemEntries == null || positionStart >= mItemEntries.length) {
-            return;
-        }
 
-        ensureSize(positionStart + itemCount);
+        for(int n = 0; n < itemCount; n++) {
+
+            int actualPosition = positionStart+n;
+            int movedPosition = positionStart+itemCount+n;
+
+            ItemEntry temp = mItemEntries.get(actualPosition);
+            mItemEntries.remove(actualPosition);
+            mItemEntries.put(movedPosition, temp);
+
+        }
 
-        System.arraycopy(mItemEntries, positionStart, mItemEntries, positionStart + itemCount,
-                mItemEntries.length - positionStart - itemCount);
-        Arrays.fill(mItemEntries, positionStart, positionStart + itemCount, null);
     }
 }

layouts/src/main/java/org/lucasr/twowayview/widget/ItemSpacingOffsets.java

@@ -50,9 +50,11 @@ private boolean isSecondLane(BaseLayoutManager lm, int itemPosition, int lane) {
             previousPosition--;
         }
 
-        final int previousLaneSpan = lm.getLaneSpanForPosition(previousPosition);
-        if (previousLane == 0) {
-            return (lane == previousLane + previousLaneSpan);
+        if(previousPosition>=0) {
+            final int previousLaneSpan = lm.getLaneSpanForPosition(previousPosition);
+            if (previousLane == 0) {
+                return (lane == previousLane + previousLaneSpan);
+            }
         }
 
         return false;