PageScrollView

PageScrollView widget that is a customized ViewGroup having function like ScrollView & ViewPager .

the sample using interaction image,both use a simple PageScrollView without nest another ViewGroup:

support basic function as below listed:

• layout orientation either Horizontal and Vertical .
• scroll any child to its start and end position to be fixed .
• interface PageTransformer , OnPageChangeListener and OnScrollChangeListener ;
• maxWidth&maxHeight,content gravity and all of its child layout_gravity .
• smooth scroll any child to its start or centre with a optional offset and anim duration.

Why to Usage

1. when you want use a simple ScrollView with some child ceiling top or bottom , or you don't like to nest a LinearLayout in it as usually,and your want a specified max width or height.
2. when you need use a ViewPager to display different width and height child and can make any selected item center parent,or need add a header or footer view to its edge.

so don't hesitate to use PageScrollView , it can support all above interaction requirement.

How to Usage

For a working implementation of this project see the app/com.rexy folder.

1. Edit layout xml file , add attr properties to PageScrollView,then include any child widgets in it just like in LinearLayout.

   <com.rexy.widget.PageScrollView                        
          android:id="@+id/pageScrollView"                
          android:layout_width="wrap_content"             
          android:layout_height="wrap_content" 
          android:layout_gravity="center" 
          android:minWidth="100dp"
          android:maxWidth="400dp"
          android:minHeight="100dp"
          android:maxHeight="900dp"
          android:orientation="horizontal" 
          android:gravity="center"                        
          rexy:childCenter="true"                         
          rexy:floatViewEndIndex="-1"                          
          rexy:floatViewStartIndex="-1"                        
          rexy:middleMargin="10dp"                        
          rexy:overFlingDistance="0dp"                    
          rexy:viewPagerStyle="true"                       
          rexy:sizeFixedPercent="0">                      
          <include layout="@layout/merge_childs_layout" />
   </com.rexy.widget.PageScrollView>                      

2. (Optional) In your onCreate method (or onCreateView for a fragment), set support properties as above attr do.

   //set PageScrollView as you need to overwriting the attr properities.
   PageScrollView scrollView = (PageScrollView)findViewById(R.id.pageScrollView);
   //layout orientation HORIZONTAL or VERTICAL.
   scrollView.setOrientation(PageScrollView.VERTICAL); 
   
   //only ViewPager style it will scroll as ViewPager and OnPageChangeListener can be efficient
   scrollView.setViewPagerStyle(false);
   
   //each item measure fixed size for percent of parent width or height.
   scrollView.setSizeFixedPercent(0);
   
   //which item to fixed scroll to start or end [0,pageScrollView.getItemCount()-1],-1 to ignore.
   scrollView.setFloatViewStartIndex(0);
   scrollView.setFloatViewEndIndex(pageScrollView.getItemCount()-1);
   
   //force layout all its childs gravity as Gravity.CENTER.
   scrollView.setChildCenter(true);
   
   //set layout margin for each item between at the layout orientation.
   scrollView.setMiddleMargin(30);
   
   //set max width or height for this container.
   scrollview.setMaxWidth(400);
   scrollview.setMaxHeigh(800);

3. (Optional) bind event for PageScrollView.

   //continued from above 
   scrollView.setPageHeadView(headerView);
   scrollView.setPageFooterView(footerView);
   scrollView.setPageTransformer(new PageScrollView.PageTransformer() {
       @Override
       public void transformPage(View view, float position, boolean horizontal) {
           //realized your transform animation for this view.
       }
       @Override
       public void recoverTransformPage(View view, boolean horizontal) {
           //clean your transform animation for this view.
       }
   });
   PageScrollView.OnPageChangeListener pagerScrollListener = new PageScrollView.OnPageChangeListener() {
       @Override
       public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
           //when selected item scroll from its center.
       }
       @Override
       public void onPageSelected(int position, int oldPosition) {
           // position current selected item ,oldPosition previous selected item
       }
       @Override
       public void onScrollChanged(int scrollX, int scrollY, int oldScrollX, int oldScrollY) {
           //when content scrolled,see View.onScrollChanged
       }
       @Override
       public void onScrollStateChanged(int state, int oldState) {
           // SCROLL_STATE_IDLE = 0; //scroll stopped .
           // SCROLL_STATE_DRAGGING = 1;//dragged scroll started .
           // SCROLL_STATE_SETTLING = 2;//fling scroll started .
       }
   };
   scrollView.setOnScrollChangeListener(pagerScrollListener);
   scrollView.setOnPageChangeListener(pagerScrollListener);