fix crash which caused by wrong position calculation

README.md

@@ -13,14 +13,14 @@ ViewPager-Layout-Manager
 如果想要自定义效果请在build.gradle文件中引入：
 
 ```Java
-compile 'rouchuan.viewpagerlayoutmanager:viewpagerlayoutmanager-core:1.2.1'
+compile 'rouchuan.viewpagerlayoutmanager:viewpagerlayoutmanager-core:1.3.0'
 ```
 [自定义教程](http://www.jianshu.com/p/b193319d35cf)
 
 如果你想用上面提供的效果，请引入（不需要再引用core）：
 
 ```groovy
-compile 'rouchuan.viewpagerlayoutmanager:viewpagerlayoutmanager-support:1.0.3'
+compile 'rouchuan.viewpagerlayoutmanager:viewpagerlayoutmanager-support:1.3.0'
 ```
 
 ### 注意!!!

README_EN.md

@@ -16,12 +16,12 @@ All you need to concern about is which the property you want to change and how i
 if you want custom your own layout manager please add code below:
 
 ```Java
-compile 'rouchuan.viewpagerlayoutmanager:viewpagerlayoutmanager-core:1.2.1'
+compile 'rouchuan.viewpagerlayoutmanager:viewpagerlayoutmanager-core:1.3.0'
 ```
 or if you want use the effect above please import(No need to import core):
 
 ```groovy
-compile 'rouchuan.viewpagerlayoutmanager:viewpagerlayoutmanager-support:1.0.3'
+compile 'rouchuan.viewpagerlayoutmanager:viewpagerlayoutmanager-support:1.3.0'
 ```
 
 ### Attention!!!

viewpagerlayoutmanager-core/build.gradle

@@ -2,7 +2,7 @@ apply plugin: 'com.android.library'
 apply plugin: 'com.github.dcendents.android-maven'
 apply plugin: 'com.jfrog.bintray'
 
-version = "1.2.1"
+version = "1.3.0"
 
 android {
     compileSdkVersion 25

viewpagerlayoutmanager-core/src/main/java/rouchuan/customlayoutmanager/ViewPagerLayoutManager.java

@@ -42,7 +42,6 @@ public abstract class ViewPagerLayoutManager extends RecyclerView.LayoutManager
     private boolean enableEndlessScroll = false;
 
     /**
-     *
      * @return the interval of each item's offset
      */
     protected abstract float setInterval();
@@ -293,7 +292,9 @@ private void layoutItems(RecyclerView.Recycler recycler,
                 if (i >= itemCount) {
                     realIndex %= itemCount;
                 } else if (i < 0) {
-                    realIndex += itemCount - (-realIndex) % itemCount;
+                    int delta = (-realIndex) % itemCount;
+                    if (delta == 0) delta = itemCount;
+                    realIndex = itemCount - delta;
                 }
                 if (findViewByPosition(i) == null) {
                     View scrap = recycler.getViewForPosition(realIndex);

viewpagerlayoutmanager-support/build.gradle

@@ -25,7 +25,7 @@ dependencies {
     compile project(path: ':viewpagerlayoutmanager-core')
 }
 
-version = "1.0.3"
+version = "1.3.0"
 
 apply plugin: 'com.github.dcendents.android-maven'
 apply plugin: 'com.jfrog.bintray'