Added code to save the current screen to handle orientation changes o…

…r any other behaviors where the activity would be destroyed.

src/com/github/ysamlan/horizontalpager/HorizontalPager.java

@@ -138,6 +138,22 @@ private void init() {
         mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
     }
 
+    @Override
+    protected Parcelable onSaveInstanceState() {
+        final SavedState state = new SavedState(super.onSaveInstanceState());
+        state.mCurrentScreen = mCurrentScreen;
+        return state;
+    }
+    
+    @Override
+    protected void onRestoreInstanceState(Parcelable state) {
+        SavedState savedState = (SavedState) state;
+        super.onRestoreInstanceState(savedState.getSuperState());
+        if (savedState.mCurrentScreen != -1) {
+        	mCurrentScreen = savedState.mCurrentScreen;
+        }
+    }
+
     @Override
     protected void onMeasure(final int widthMeasureSpec, final int heightMeasureSpec) {
         super.onMeasure(widthMeasureSpec, heightMeasureSpec);
@@ -501,4 +517,36 @@ private void snapToScreen(final int whichScreen, final int duration) {
          */
         void onScreenSwitched(int screen);
     }
+
+    /**
+     * A parcelable so we can save our current screen and return to it after an activity destroy.
+     */
+    public static class SavedState extends BaseSavedState {
+        int mCurrentScreen = -1;
+
+        SavedState(Parcelable superState) {
+            super(superState);
+        }
+
+        private SavedState(Parcel in) {
+            super(in);
+            mCurrentScreen = in.readInt();
+        }
+
+        @Override
+        public void writeToParcel(Parcel out, int flags) {
+            super.writeToParcel(out, flags);
+            out.writeInt(mCurrentScreen);
+        }
+
+        public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() {
+            public SavedState createFromParcel(Parcel in) {
+                return new SavedState(in);
+            }
+
+            public SavedState[] newArray(int size) {
+                return new SavedState[size];
+            }
+        };
+    }
 }