android - ReyclerView - programmatically scroll with predefined time -

i need dragging similar action on recyclerview , when reach top or bottom end of recyclerview want scroll smoothly...

i following: post runnable scroll until user not near enough start/end of recyclerview anymore.

mscroll = new runnable() {         @override         public void run() {             rvimages.smoothscrollby(0, mscrolldist.get());             mhandler.postdelayed(mscroll, 100);         }     }; 

the problem, need define, scrolling desired distance should done in 100ms, overall scrolling smooth.

how can achieve that?

use custom linearlayoutmanager

     public class mycustomlayoutmanager extends linearlayoutmanager {             //we need mcontext create our linearsmoothscroller             private context mcontext;              public mycustomlayoutmanager(context context) {                 super(context);                 mcontext = context;             }              //override method? check.             @override             public void smoothscrolltoposition(recyclerview recyclerview,                 recyclerview.state state, int position) {                  //create recyclerview.smoothscroller instance? check.                 linearsmoothscroller smoothscroller =                      new linearsmoothscroller(mcontext) {                      //automatically implements method on instantiation.                     @override     public pointf computescrollvectorforposition(int targetposition) {         //what pointf? class holds 2 float coordinates.         //accepts (x , y)         //for y: use -1 direction, 1 down direction.         //for x (did not test): use -1 left direction, 1 right         //direction.         //we let our custom linearlayoutmanager calculate pointf         return mycustomlayoutmanager.this.computescrollvectorforposition             (targetposition);     } };                  //docs not tell this,                 //but need set position want scroll to.                 smoothscroller.settargetposition(position);                  //call startsmoothscroll(smoothscroller)? check.                 startsmoothscroll(smoothscroller);             }         } 

customizing scrool speed

//make instance variable @ top of custom layoutmanager private static final float milliseconds_per_inch = 50f;     .     .     .     linearsmoothscroller smoothscroller =          new linearsmoothscroller(mcontext) {         .         .         .         //the holy grail of smooth scrolling         //returns milliseconds takes scroll 1 pixel.         @override         protected float calculatespeedperpixel             (displaymetrics displaymetrics) {             return milliseconds_per_inch / displaymetrics.densitydpi;         }     }; 

in activity:

mlayoutmanager = new mycustomlayoutmanager(getactivity()); mrecyclerview.setlayoutmanager(mlayoutmanager); mrecyclerview.smoothscrolltoposition(position); 

source code