Added looping feature.

Author: Alexander Mikhalevich

README.md

@@ -125,6 +125,8 @@ Currently SwipeStack implements the following callbacks:
 
 `disable_hw_acceleration` set to `true` disables hardware acceleration. *Default: false*
 
+`looped` set to `true` enables looping. *Default: false*
+
 ## Copyright Notice ##
 ``` 
 Copyright (C) 2016 Frederik Schweiger

build.gradle

@@ -5,7 +5,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.0.0-beta5'
+        classpath 'com.android.tools.build:gradle:2.1.0'
         classpath 'com.novoda:bintray-release:0.3.4'
     }
 }

library/src/main/java/link/fls/swipestack/SwipeStack.java

@@ -44,6 +44,7 @@ public class SwipeStack extends ViewGroup {
     public static final float DEFAULT_SWIPE_OPACITY = 1f;
     public static final float DEFAULT_SCALE_FACTOR = 1f;
     public static final boolean DEFAULT_DISABLE_HW_ACCELERATION = true;
+    public static final boolean DEFAULT_IS_LOOPED = false;
 
     private static final String KEY_SUPER_STATE = "superState";
     private static final String KEY_CURRENT_INDEX = "currentIndex";
@@ -53,7 +54,7 @@ public class SwipeStack extends ViewGroup {
 
     private int mAllowedSwipeDirections;
     private int mAnimationDuration;
-    private int mCurrentViewIndex;
+    private int mCurrentIndex;
     private int mNumberOfStackedViews;
     private int mViewSpacing;
     private int mViewRotation;
@@ -62,6 +63,7 @@ public class SwipeStack extends ViewGroup {
     private float mScaleFactor;
     private boolean mDisableHwAcceleration;
     private boolean mIsFirstLayout = true;
+    private boolean mIsLooped;
 
     private View mTopView;
     private SwipeHelper mSwipeHelper;
@@ -109,6 +111,9 @@ private void readAttributes(AttributeSet attributeSet) {
             mDisableHwAcceleration =
                     attrs.getBoolean(R.styleable.SwipeStack_disable_hw_acceleration,
                             DEFAULT_DISABLE_HW_ACCELERATION);
+            mIsLooped =
+                    attrs.getBoolean(R.styleable.SwipeStack_looped,
+                            DEFAULT_IS_LOOPED);
         } finally {
             attrs.recycle();
         }
@@ -139,32 +144,36 @@ public void onChanged() {
     public Parcelable onSaveInstanceState() {
         Bundle bundle = new Bundle();
         bundle.putParcelable(KEY_SUPER_STATE, super.onSaveInstanceState());
-        bundle.putInt(KEY_CURRENT_INDEX, mCurrentViewIndex - getChildCount());
+        bundle.putInt(KEY_CURRENT_INDEX, mCurrentIndex - getChildCount());
         return bundle;
     }
 
     @Override
     public void onRestoreInstanceState(Parcelable state) {
         if (state instanceof Bundle) {
             Bundle bundle = (Bundle) state;
-            mCurrentViewIndex = bundle.getInt(KEY_CURRENT_INDEX);
+            mCurrentIndex = bundle.getInt(KEY_CURRENT_INDEX);
             state = bundle.getParcelable(KEY_SUPER_STATE);
         }
 
         super.onRestoreInstanceState(state);
     }
 
+    private int getCurrentViewIndex() {
+        return mCurrentIndex % mAdapter.getCount();
+    }
+
     @Override
     protected void onLayout(boolean changed, int l, int t, int r, int b) {
 
         if (mAdapter == null || mAdapter.isEmpty()) {
-            mCurrentViewIndex = 0;
+            mCurrentIndex = 0;
             removeAllViewsInLayout();
             return;
         }
 
         for (int x = getChildCount();
-             x < mNumberOfStackedViews && mCurrentViewIndex < mAdapter.getCount();
+             x < mNumberOfStackedViews && (mIsLooped || mCurrentIndex < mAdapter.getCount());
              x++) {
             addNextView();
         }
@@ -175,8 +184,8 @@ protected void onLayout(boolean changed, int l, int t, int r, int b) {
     }
 
     private void addNextView() {
-        if (mCurrentViewIndex < mAdapter.getCount()) {
-            View bottomView = mAdapter.getView(mCurrentViewIndex, null, this);
+        if (getCurrentViewIndex() < mAdapter.getCount()) {
+            View bottomView = mAdapter.getView(getCurrentViewIndex(), null, this);
             bottomView.setTag(R.id.new_view, true);
 
             if (!mDisableHwAcceleration) {
@@ -211,7 +220,7 @@ private void addNextView() {
             bottomView.measure(measureSpecWidth | width, measureSpecHeight | height);
             addViewInLayout(bottomView, 0, params, true);
 
-            mCurrentViewIndex++;
+            mCurrentIndex++;
         }
     }
 
@@ -301,7 +310,7 @@ public void onSwipeEnd() {
     }
 
     public void onViewSwipedToLeft() {
-        if (mListener != null) mListener.onViewSwipedToLeft(getCurrentPosition());
+        if (mListener != null) mListener.onViewSwipedToRight(getCurrentPosition());
         removeTopView();
     }
 
@@ -316,7 +325,7 @@ public void onViewSwipedToRight() {
      * @return The current position.
      */
     public int getCurrentPosition() {
-        return mCurrentViewIndex - getChildCount();
+        return (mCurrentIndex - getChildCount()) % mAdapter.getCount();
     }
 
     /**
@@ -410,7 +419,7 @@ public void swipeTopViewToLeft() {
      * Resets the current adapter position and repopulates the stack.
      */
     public void resetStack() {
-        mCurrentViewIndex = 0;
+        mCurrentIndex = 0;
         removeAllViewsInLayout();
         requestLayout();
     }

library/src/main/res/values/attrs.xml

@@ -14,5 +14,6 @@
         <attr name="swipe_opacity" format="float"/>
         <attr name="scale_factor" format="float"/>
         <attr name="disable_hw_acceleration" format="boolean"/>
+        <attr name="looped" format="boolean"/>
     </declare-styleable>
 </resources>