自定義view 三角形路徑繪制

package com.sero.vk.signNow.ViewBezier;

import android.animation.ValueAnimator;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.DashPathEffect;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PathEffect;
import android.graphics.PathMeasure;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.LinearInterpolator;

/**
 * Created by Administrator on 2017/3/1.
 */

public class MyPathTracingView extends View implements View.OnClickListener {

    private Paint paint;
    private Path path;
    private PathMeasure pathMeasure;
    private float length;
    private float mAnimationValue;
    private PathEffect pathEffect;

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

    public MyPathTracingView(Context context, AttributeSet attrs) {
        super(context, attrs);
        paint = new Paint(Paint.ANTI_ALIAS_FLAG);
        paint.setStrokeWidth(3);
        paint.setStyle(Paint.Style.STROKE);
        paint.setColor(Color.RED);

        path = new Path();
        path.moveTo(100, 100);
        path.lineTo(100, 500);
        path.lineTo(400, 300);
        path.close();

        pathMeasure = new PathMeasure();
        pathMeasure.setPath(path,true);
        length = pathMeasure.getLength();

        ValueAnimator animator = ValueAnimator.ofFloat(1, 0);
        animator.setInterpolator(new LinearInterpolator());
        animator.setRepeatCount(ValueAnimator.INFINITE);
        animator.setDuration(2000);
        animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                mAnimationValue = (float) animation.getAnimatedValue();
                pathEffect = new DashPathEffect(new float[]{length, length}, 
                        length * mAnimationValue);
                paint.setPathEffect(pathEffect);
                invalidate();
            }
        });
        animator.start();

    }

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

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawPath(path, paint);

    }


    @Override
    public void onClick(View v) {

    }
}