Animate an Object With a Custom Interpolator in Xamarin.Android



Today we're gonna make a simple scale animation with a Custom Interpolator, look the code

using System;
using Android.App;
using Android.Content;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;
using Android.Animation;
using Android.Views.Animations;

namespace HeartBeat
{
 [Activity (Label = "HeartBeat", MainLauncher = true)]
 public class MainActivity : Activity
 {
  protected override void OnCreate (Bundle bundle)
  {
   base.OnCreate (bundle);
   // Set our view from the "main" layout resource
   //SetContentView (Resource.Layout.Main);
   ImageView img = new ImageView (this);
   //set heart image to imageview
   img.SetImageResource (Resource.Drawable.Heart);
   //Set the imageview as a content view
   SetContentView (img);

   //Create an action
   Action act = new Action (() => {
    //Create an instance of our custom interpolator
    customInterpolator i = new customInterpolator ();
    //Create an Scale Animation(fromX,toX,fromY,toY,pivotX,pivotY)
    ScaleAnimation anim = new ScaleAnimation (1, 1.2f, 1, 1.2f, img.Width / 2, img.Height / 2);
    //Set repeat count to infinite
    anim.RepeatCount = Animation.Infinite;
    //Set the animation duration
    anim.Duration = 750;
    //Set the animation custom interpolator
    anim.Interpolator = i;
    //Attach our Custom Scale Animation to the imageview
    img.StartAnimation (anim);
   });
   //Post the action to the imageview
   img.Post (act);
  }
 }

 //Custom interpolator implementing Java Object class and IInterpolator interface
 public class customInterpolator:Java.Lang.Object, IInterpolator
 {
  //implement the GetInterpolation Method from IInterpolator Interface
  public float GetInterpolation (float input)
  {
   float x = input < 1/3f? 2 * input : (1 + input) / 2;
   return (float) Math.Sin(x * Math.PI);
  }
 }
}

Now you can see the result


Full Code at GitHub: https://github.com/AlejandroRuiz/Mono/tree/master/HeartBeat

If you have a question feel free to ask me


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