ChartViewportAnimatorV8.java

package lecho.lib.hellocharts.animation;

import android.os.Handler;
import android.os.SystemClock;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.view.animation.Interpolator;

import lecho.lib.hellocharts.model.Viewport;
import lecho.lib.hellocharts.view.Chart;

public class ChartViewportAnimatorV8 implements ChartViewportAnimator {

    final Chart chart;
    final Handler handler;
    final Interpolator interpolator = new AccelerateDecelerateInterpolator();
    long start;
    boolean isAnimationStarted = false;
    private Viewport startViewport = new Viewport();
    private Viewport targetViewport = new Viewport();
    private Viewport newViewport = new Viewport();
    private long duration;
    private ChartAnimationListener animationListener = new DummyChartAnimationListener();
    private final Runnable runnable = new Runnable() {

        @Override
        public void run() {
            long elapsed = SystemClock.uptimeMillis() - start;
            if (elapsed > duration) {
                isAnimationStarted = false;
                handler.removeCallbacks(runnable);
                chart.setCurrentViewport(targetViewport);
                animationListener.onAnimationFinished();
                return;
            }
            float scale = Math.min(interpolator.getInterpolation((float) elapsed / duration), 1);
            float diffLeft = (targetViewport.left - startViewport.left) * scale;
            float diffTop = (targetViewport.top - startViewport.top) * scale;
            float diffRight = (targetViewport.right - startViewport.right) * scale;
            float diffBottom = (targetViewport.bottom - startViewport.bottom) * scale;
            newViewport.set(startViewport.left + diffLeft, startViewport.top + diffTop,
                    startViewport.right + diffRight, startViewport.bottom + diffBottom);
            chart.setCurrentViewport(newViewport);

            handler.postDelayed(this, 16);
        }
    };

    public ChartViewportAnimatorV8(Chart chart) {
        this.chart = chart;
        this.duration = FAST_ANIMATION_DURATION;
        this.handler = new Handler();
    }

    @Override
    public void startAnimation(Viewport startViewport, Viewport targetViewport) {
        this.startViewport.set(startViewport);
        this.targetViewport.set(targetViewport);
        duration = FAST_ANIMATION_DURATION;
        isAnimationStarted = true;
        animationListener.onAnimationStarted();
        start = SystemClock.uptimeMillis();
        handler.post(runnable);
    }

    @Override
    public void startAnimation(Viewport startViewport, Viewport targetViewport, long duration) {
        this.startViewport.set(startViewport);
        this.targetViewport.set(targetViewport);
        this.duration = duration;
        isAnimationStarted = true;
        animationListener.onAnimationStarted();
        start = SystemClock.uptimeMillis();
        handler.post(runnable);
    }

    @Override
    public void cancelAnimation() {
        isAnimationStarted = false;
        handler.removeCallbacks(runnable);
        chart.setCurrentViewport(targetViewport);
        animationListener.onAnimationFinished();
    }

    @Override
    public boolean isAnimationStarted() {
        return isAnimationStarted;
    }

    @Override
    public void setChartAnimationListener(ChartAnimationListener animationListener) {
        if (null == animationListener) {
            this.animationListener = new DummyChartAnimationListener();
        } else {
            this.animationListener = animationListener;
        }
    }


}