//  BouncingBallsAnimationActivity.java  by Kari Laitinen

//  http://www.naturalprogramming.com/

//  2012-09-13  File created.
//  2012-09-14  Last modification.


/*  This is a modified verion of BouncingBalls.java from the standard
    Android sample applications.


    More information related to animation in Android:
    http://developer.android.com/guide/topics/graphics/index.html
*/

package bouncing.balls.animation;

import android.graphics.drawable.ColorDrawable;

import android.animation.*;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.RadialGradient;
import android.graphics.Shader;
import android.graphics.drawable.ShapeDrawable;
import android.graphics.drawable.shapes.OvalShape;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.AccelerateInterpolator;
import android.view.animation.DecelerateInterpolator;
import android.widget.LinearLayout;

import java.util.ArrayList;


public class BouncingBallsAnimationActivity extends Activity
{
    /** Called when the activity is first created. */
    @Override
   public void onCreate(Bundle savedInstanceState)
   {
      super.onCreate(savedInstanceState);

      setContentView( new MyAnimationView( this ) ) ;

      //setContentView(R.layout.bouncing_balls);
      //LinearLayout container = (LinearLayout) findViewById(R.id.container);
      //container.addView(new MyAnimationView(this));
   }

   public class MyAnimationView extends View
   {
      private static final int RED = 0xffFF8080;
      private static final int BLUE = 0xff8080FF;
      private static final int CYAN = 0xff80ffff;
      private static final int GREEN = 0xff80ff80;

      public final ArrayList<ShapeHolder> balls = new ArrayList<ShapeHolder>();
      AnimatorSet animation = null;

      public MyAnimationView( Context context )
      {
         super(context);

         // The following animator will automatically generate calls to the
         // setBackgroundColor() method of this object.

         // Note that setting the background color will automatically invalidate the
         // view, so that the animated color, and the bouncing balls, get redisplayed on
         // every frame of the animation.

         ValueAnimator background_color_animator =
                    ObjectAnimator.ofInt( this, "backgroundColor", RED, BLUE ) ;
         background_color_animator.setDuration( 3000 ) ;
         background_color_animator.setEvaluator( new ArgbEvaluator() ) ;
         background_color_animator.setRepeatCount( ValueAnimator.INFINITE ) ;
         background_color_animator.setRepeatMode( ValueAnimator.REVERSE ) ;
         background_color_animator.start() ;
      }

      @Override
      public boolean onTouchEvent(MotionEvent event)
      {
         if (event.getAction() != MotionEvent.ACTION_DOWN &&
                 event.getAction() != MotionEvent.ACTION_MOVE) {
             return false;
         }

         ShapeHolder newBall = addBall(event.getX(), event.getY());

         // Bouncing animation with squash and stretch
         float startY = newBall.getY();
         float endY = getHeight() - 50f;
         float h = (float)getHeight();
         float eventY = event.getY();
         int duration = (int)(500 * ((h - eventY)/h));

         ValueAnimator bounceAnim = ObjectAnimator.ofFloat(newBall, "y", startY, endY);
         bounceAnim.setDuration(duration);
         bounceAnim.setInterpolator(new AccelerateInterpolator());

         ValueAnimator squashAnim1 = ObjectAnimator.ofFloat(newBall, "x", newBall.getX(),
                    newBall.getX() - 25f);
         squashAnim1.setDuration(duration/4);
         squashAnim1.setRepeatCount(1);
         squashAnim1.setRepeatMode(ValueAnimator.REVERSE);
         squashAnim1.setInterpolator(new DecelerateInterpolator());

         ValueAnimator squashAnim2 = ObjectAnimator.ofFloat(newBall, "width", newBall.getWidth(),
                    newBall.getWidth() + 50);
         squashAnim2.setDuration(duration/4);
         squashAnim2.setRepeatCount(1);
         squashAnim2.setRepeatMode(ValueAnimator.REVERSE);
         squashAnim2.setInterpolator(new DecelerateInterpolator());

         ValueAnimator stretchAnim1 = ObjectAnimator.ofFloat(newBall, "y", endY,
                    endY + 25f);
         stretchAnim1.setDuration(duration/4);
         stretchAnim1.setRepeatCount(1);
         stretchAnim1.setInterpolator(new DecelerateInterpolator());
         stretchAnim1.setRepeatMode(ValueAnimator.REVERSE);

         ValueAnimator stretchAnim2 = ObjectAnimator.ofFloat(newBall, "height",
                    newBall.getHeight(), newBall.getHeight() - 25);
         stretchAnim2.setDuration(duration/4);
         stretchAnim2.setRepeatCount(1);
         stretchAnim2.setInterpolator(new DecelerateInterpolator());
         stretchAnim2.setRepeatMode(ValueAnimator.REVERSE);

         ValueAnimator bounceBackAnim = ObjectAnimator.ofFloat(newBall, "y", endY,
                    startY);
         bounceBackAnim.setDuration(duration);
         bounceBackAnim.setInterpolator(new DecelerateInterpolator());

         // Sequence the down/squash&stretch/up animations

         AnimatorSet bouncer = new AnimatorSet() ;
         bouncer.play(bounceAnim).before(squashAnim1);
         bouncer.play(squashAnim1).with(squashAnim2);
         bouncer.play(squashAnim1).with(stretchAnim1);
         bouncer.play(squashAnim1).with(stretchAnim2);
         bouncer.play(bounceBackAnim).after(stretchAnim2);

         // Fading animation - remove the ball when the animation is done
         ValueAnimator final_fading_animator =
                           ObjectAnimator.ofFloat(newBall, "alpha", 1f, 0f);
         final_fading_animator.setDuration( 250 ) ;
         final_fading_animator.addListener( new AnimatorListenerAdapter()
         {
            @Override
            public void onAnimationEnd( Animator animation )
            {
               balls.remove( ((ObjectAnimator)animation).getTarget() ) ;

            }
         });

            // Sequence the two animations to play one after the other
         AnimatorSet animatorSet = new AnimatorSet();
         animatorSet.play(bouncer).before( final_fading_animator ) ;

         // Start the animation
         animatorSet.start();

         return true;
      }

      private ShapeHolder addBall(float x, float y)
      {
         OvalShape circle = new OvalShape();
         circle.resize(50f, 50f);
         ShapeDrawable drawable = new ShapeDrawable( circle ) ;
         ShapeHolder shapeHolder = new ShapeHolder(drawable);
         shapeHolder.setX(x - 25f);
         shapeHolder.setY(y - 25f);
         int red = (int)(Math.random() * 255);
         int green = (int)(Math.random() * 255);
         int blue = (int)(Math.random() * 255);
         int color = 0xff000000 | red << 16 | green << 8 | blue;
         Paint paint = drawable.getPaint(); //new Paint(Paint.ANTI_ALIAS_FLAG);
         int darkColor = 0xff000000 | red/4 << 16 | green/4 << 8 | blue/4;
         RadialGradient gradient = new RadialGradient(37.5f, 12.5f,
                    50f, color, darkColor, Shader.TileMode.CLAMP);
         paint.setShader(gradient);
         shapeHolder.setPaint(paint);
         balls.add(shapeHolder);
         return shapeHolder;
      }

      @Override
      protected void onDraw( Canvas canvas )
      {
         for (int i = 0; i < balls.size(); ++i) {
            ShapeHolder shapeHolder = balls.get(i);
            canvas.save();
            canvas.translate(shapeHolder.getX(), shapeHolder.getY());
            shapeHolder.getShape().draw(canvas);
            canvas.restore();
         }
      }
   }
}