package com.example.sdj.testfn.attributeAnimation;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.View;

/**
 * 项目名称：code
 * 类描述：
 * 创建人：sdj
 * 创建时间：2019/6/25 15:46
 * 修改人：sdj
 * 修改时间：2019/6/25 15:46
 * 修改备注：
 */
public class PercentageCircle extends View {
    private float sweepAngle;

    public float getSweepAngle() {
        return sweepAngle;
    }

    public void setSweepAngle(float sweepAngle) {
        this.sweepAngle = sweepAngle;
        invalidate();
    }

    public PercentageCircle(Context context) {
        super(context);
    }

    public PercentageCircle(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public PercentageCircle(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
       // canvas.drawColor(Color.parseColor("#f200ff00"));
        Paint p = new Paint();
        p.setAntiAlias(true);
        p.setStyle(Paint.Style.STROKE);
       // p.setStrokeWidth(4);
        p.setColor(Color.parseColor("#ff0000"));

        Paint textP = new Paint();
        textP.setAntiAlias(true);
        textP.setStyle(Paint.Style.STROKE);
        textP.setTextSize(16);
        textP.setColor(Color.parseColor("#ff0000"));

        Paint bg= new Paint();
        bg.setAntiAlias(true);
        bg.setStyle(Paint.Style.FILL);
        bg.setColor(Color.parseColor("#F100ff00"));
        
        canvas.drawArc(4,4,getWidth()-4,getHeight()-4,0,sweepAngle,false,p);

        int v = (int) (sweepAngle / 360 *100);
        String num = v+"%";


        float x = getWidth()/2-TextSizeUtils.getFontWeight(num,p)/2;
        int y = getHeight()/2+TextSizeUtils.getFontHeight(num,p)/2;
    
        canvas.drawText(num,x,y,textP);

      //  canvas.drawRect(0,0,getWidth(),getHeight(),bg);
    }
}

以百分比进度条为例

属性动画在自定义View中的应用

1，添加自定义属性

sweepAngle --代表加载的角度（0-360）

2，添加get,set方法

3，根据sweepAngle 绘制，完成属性动画自定义View部分的内容

4，开启动画：

ObjectAnimator.ofFloat(percentageCircle,"sweepAngle",0,360).setDuration(4000).start();

属性动画的操作流程大概就这样，接下来分析一下自定义Evaluator

默认情况下：

ofInt()---对应---IntEvaluator

ofFloat()---对应---FloatEvaluator

通过setEvaluator 设置自定义的Evaluator,继承TypeEvaluator

package com.example.sdj.testfn.attributeAnimation;

import android.animation.TypeEvaluator;
import android.graphics.Color;

/**
 * 项目名称：code
 * 类描述：
 * 创建人：sdj
 * 创建时间：2019/6/25 15:23
 * 修改人：sdj
 * 修改时间：2019/6/25 15:23
 * 修改备注：
 */
public class MyArgbEvaluator implements TypeEvaluator<Integer> {

    @Override
    public Integer evaluate(float fraction, Integer startValue, Integer endValue) {
        float [] startHsv = new float[3];
        float [] endHsv = new float[3];
        float [] outHsv = new float[3];
        Color.colorToHSV(startValue,startHsv);
        Color.colorToHSV(endValue,endHsv);

        outHsv[0] = startHsv[0]+(endHsv[0]-startHsv[0])*fraction;
        outHsv[1] = startHsv[1]+(endHsv[1]-startHsv[1])*fraction;
        outHsv[2] = startHsv[2]+(endHsv[2]-startHsv[2])*fraction;
        int alpha = 0x99;
        return Color.HSVToColor(alpha,outHsv);
    }
}

重写evaluate方法，编写估值算法，泛型可以为Point,或者其他自定义类型