ColorTypeEvaluatorView.java

package com.cui.trypro.widget;

import android.animation.AnimatorSet;
import android.animation.ObjectAnimator;
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.util.AttributeSet;
import android.util.Log;
import android.view.View;

import com.cui.trypro.bean.Point;
import com.cui.trypro.utils.ColorEvaluator;

/**
 * Created by cuiyang on 15/8/28.
 */
public class ColorTypeEvaluatorView extends View {
    public static final float RADIUS = 50f;

    private Point currentPoint;

    private Paint mPaint;

    private String color;

    private int mCurrentRed = -1;

    private int mCurrentGreen = -1;

    private int mCurrentBlue = -1;

    public ColorTypeEvaluatorView(Context context) {
        super(context);
        init();
    }

    public ColorTypeEvaluatorView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();

    }

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

    }

    private void init() {
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setColor(Color.BLUE);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        if (currentPoint == null) {
            currentPoint = new Point(RADIUS, RADIUS);
            drawCircle(canvas);
            startAnimation();
        } else {
            drawCircle(canvas);
        }

    }

    private void drawCircle(Canvas canvas) {
        float x = currentPoint.getX();
        float y = currentPoint.getY();
        canvas.drawCircle(x, y, RADIUS, mPaint);
    }

    private void startAnimation() {
        Point startPoint = new Point(RADIUS, RADIUS);
        Point endPoint = new Point(getWidth() - RADIUS, getHeight() - RADIUS);
        ValueAnimator anim = ValueAnimator.ofObject(new PointEvaluator(), startPoint, endPoint);
        anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                currentPoint = (Point) animation.getAnimatedValue();
                invalidate();
            }
        });


        /**
         * 以看到，我们并没有改动太多的代码，重点只是修改了startAnimation()方法中的部分内容。这里先是将颜色过
         * 度的代码逻辑移动到了startAnimation()方法当中，注意由于这段代码本身就是在MyAnimView当中执行的，因
         * 此ObjectAnimator.ofObject()的第一个参数直接传this就可以了。接着我们又创建了一个AnimatorSet，并
         * 把两个动画设置成同时播放，动画时长为五秒，最后启动动画。现在重新运行一下代码，效果如下图所示：

         * */
        ObjectAnimator anim2 = ObjectAnimator.ofObject(this, "color", new ColorEvaluator(),
                "#0000FF", "#FF0000");
        AnimatorSet animSet = new AnimatorSet();
        animSet.play(anim).with(anim2);
        animSet.setDuration(5000);
        animSet.start();
    }

    public void setColor(String color) {
        this.color = color;
        mPaint.setColor(Color.parseColor(color));
        invalidate();
    }

    public String getColor() {
        return color;
    }

    public class PointEvaluator implements TypeEvaluator {

        @Override
        public Object evaluate(float fraction, Object startValue, Object endValue) {
            Point startPoint = (Point) startValue;
            Point endPoint = (Point) endValue;
            float x = startPoint.getX() + fraction * (endPoint.getX() - startPoint.getX());
            float y = startPoint.getY() + fraction * (endPoint.getY() - startPoint.getY());
            Point point = new Point(x, y);
            return point;
        }
    }
}