CubicToSample

CubicToSample.java

import android.animation.TypeEvaluator;
import android.animation.ValueAnimator;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.AccelerateDecelerateInterpolator;

/**
 * Created by amyu on 15/05/20
 */
public class CubicToSample extends View {

    private Paint mPaint;

    private int mWidth;

    private Path mWavePath;

    private static final float[][] WAVE_CURRENT_POINT_1 = {
            {0.0f, 0.0f},
            {0.125f, 0.1f},
            {0.25f, 0.25f},
            {0.5f, 0.1f},
            {0.75f, 0.25f},
            {0.875f, 0.1f},
            {1.0f, 0.0f}
    };

    private static final float[][] WAVE_CURRENT_POINT_2 = {
            {0.0f, 0.0f},
            {0.125f, 0.1f},
            {0.3f, 0.02f},
            {0.5f, 0.2f},
            {0.7f, 0.02f},
            {0.875f, 0.1f},
            {1.0f, 0.0f}
    };

    private static final float[][] WAVE_CONTROL_POINT1_1 = {
            {0.0602f, 0.0f},
            {0.1718f, 0.1771f},
            {0.316f, 0.2476f},
            {0.5631f, 0.0976f},
            {0.8101f, 0.2523f},
            {0.9029f, 0.0491f}
    };

    private static final float[][] WAVE_CONTROL_POINT1_2 = {
            {0.0602f, 0.0f},
            {0.1718f, 0.1771f},
            {0.3631f, 0.02f},
            {0.5691f, 0.204f},
            {0.7631f, 0.02f},
            {0.9029f, 0.0491f}
    };

    private static final float[][] WAVE_CONTROL_POINT2_1 = {
            {0.0941f, 0.0491f},
            {0.1869f, 0.2523f},
            {0.434f, 0.0976f},
            {0.681f, 0.2476f},
            {0.8252f, 0.1771f},
            {0.9368f, 0.0f}
    };

    private static final float[][] WAVE_CONTROL_POINT2_2 = {
            {0.0941f, 0.0491f},
            {0.2369f, 0.02f},
            {0.4311f, 0.204f},
            {0.6369f, 0.02f},
            {0.8252f, 0.1771f},
            {0.9368f, 0.0f}
    };

    public CubicToSample(Context context) {
        this(context, null, 0);
    }

    public CubicToSample(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public CubicToSample(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        initView();
    }

    private void initView() {
        setUpPaint();
        setUpPath();
        setUpAnimator();
    }

    private void setUpAnimator() {
        mWaveControl1Animator = ValueAnimator.ofObject(new WaveTypeEvaluator(), WAVE_CONTROL_POINT1_1, WAVE_CONTROL_POINT1_1);
        mWaveControl1Animator.start();

        mWaveControl2Animator = ValueAnimator.ofObject(new WaveTypeEvaluator(), WAVE_CONTROL_POINT2_1, WAVE_CONTROL_POINT2_1);
        mWaveControl2Animator.start();

        mWavePositionAnimator = ValueAnimator.ofObject(new WaveTypeEvaluator(), WAVE_CURRENT_POINT_1, WAVE_CURRENT_POINT_1);
        mWavePositionAnimator.start();
    }

    private void setUpPaint() {
        mPaint = new Paint();
        mPaint.setColor(Color.RED);
        mPaint.setAntiAlias(true);
        mPaint.setStyle(Paint.Style.FILL);
    }

    private void setUpPath() {
        mWavePath = new Path();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        mWavePath.reset();
        mWavePath.moveTo(WAVE_CURRENT_POINT_2[0][0], WAVE_CURRENT_POINT_2[0][1]);
        float[][] controlPoint1 = (float[][]) mWaveControl1Animator.getAnimatedValue();
        float[][] controlPoint2 = (float[][]) mWaveControl2Animator.getAnimatedValue();

        float[][] endPoint = (float[][]) mWavePositionAnimator.getAnimatedValue();
        for (int i = 0; i < 6; i++) {
            mWavePath.cubicTo(
                    controlPoint1[i][0] * mWidth, controlPoint1[i][1] * 1000,
                    controlPoint2[i][0] * mWidth, controlPoint2[i][1] * 1000,
                    endPoint[i + 1][0] * mWidth, endPoint[i + 1][1] * 1000
            );
        }
        canvas.drawPath(mWavePath, mPaint);
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        mWidth = w;
        super.onSizeChanged(w, h, oldw, oldh);
    }


    private ValueAnimator mWaveControl1Animator;

    private ValueAnimator mWaveControl2Animator;

    private ValueAnimator mWavePositionAnimator;

    public void startWaveAnimation() {
        mWaveControl1Animator = ValueAnimator.ofObject(new WaveTypeEvaluator(), WAVE_CONTROL_POINT1_1, WAVE_CONTROL_POINT1_2);
        mWaveControl1Animator.setDuration(500);
        mWaveControl1Animator.addUpdateListener(mAnimatorUpdateListener);
        mWaveControl1Animator.start();

        mWaveControl2Animator = ValueAnimator.ofObject(new WaveTypeEvaluator(), WAVE_CONTROL_POINT2_1, WAVE_CONTROL_POINT2_2);
        mWaveControl2Animator.setDuration(500);
        mWaveControl2Animator.addUpdateListener(mAnimatorUpdateListener);
        mWaveControl2Animator.start();

        mWavePositionAnimator = ValueAnimator.ofObject(new WaveTypeEvaluator(), WAVE_CURRENT_POINT_1, WAVE_CURRENT_POINT_2);
        mWavePositionAnimator.setDuration(500);
        mWavePositionAnimator.addUpdateListener(mAnimatorUpdateListener);
        mWavePositionAnimator.setInterpolator(new AccelerateDecelerateInterpolator());
        mWavePositionAnimator.start();

    }

    private ValueAnimator.AnimatorUpdateListener mAnimatorUpdateListener = new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator valueAnimator) {
            invalidate();
        }
    };

    public static class WaveTypeEvaluator implements TypeEvaluator<float[][]> {

        @Override
        public float[][] evaluate(float v, float[][] start, float[][] end) {
            float[][] newValue = new float[start.length][start[0].length];

            for (int i = 0; i < start.length; i++) {
                for (int j = 0; j < start[i].length; j++) {
                    newValue[i][j] = start[i][j] + (end[i][j] - start[i][j]) * v;
                }
            }
            return newValue;
        }
    }
}