Android实现支付宝AR扫描动画效果

支付宝AR扫描效果动画实现，具体内容如下

之前一个网友说想要一个支付宝扫描动画的效果demo,所以又花了点时间做了下这个东西,先看效果图

说一下实现的思路,如图中最外围的蓝色的是用两个相距180°的圆弧实现的,再往里又是两个红色的圆弧再往里面是一个红色的圆,最里面的白色的是由4个间隔的白色圆弧组成的,其实说明白的就是简单的图形的堆积.然后通过控制绘制圆弧的起始角度进行旋转的动画.扫描的红色线条是一张渐变的图片,通过平移动画实现扫描的效果.

这个自定义View 的代码如下:

package cn.com.hadon.scanner;

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

/**
 * Created by Mr.Wang on 2017/5/8.
 */

public class ScanView extends View {
 private Paint blueCirclePaint;//蓝色圈的画笔
 private Paint redCirclePaint;//红色圈的画笔
 private Paint whiteCirclePaint;//白色圈的画笔

 public static final int STATE_READY = 1;
 public static final int STATE_SCANING = 2;
 public static final int STATE_SUCCESS = 3;

 //定义圆弧的宽度
 private static final int BLUE_CIRCLE_BORDER_WIDTH = 8;
 private static final int INSIDER_RED_CIRCLE_BORDER_WIDTH = 20;
 private static final int OUTSIDER_CIRCLE_BORDER_WIDTH = 20;
 private static final int WHITE_CIRCLE_BORDER_WIDTH = 20;

 private int minLength;//中心最大圆的直径
 private int radius;//中心最大圆的半径
 private int centerX;//中心点X坐标
 private int centerY;//中心点Y坐标

 private Bitmap scanerbitmap;//条形扫描图片
 private int curState = STATE_SCANING;//初始状态

 public ScanView(Context context, @Nullable AttributeSet attrs) {
  super(context, attrs);
  //初始化一些变量
  scanerbitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.scaner);
  blueCirclePaint = new Paint();
  redCirclePaint = new Paint();
  whiteCirclePaint = new Paint();

  blueCirclePaint.setColor(Color.BLUE);
  blueCirclePaint.setAntiAlias(true);
  blueCirclePaint.setStyle(Paint.Style.STROKE);
  blueCirclePaint.setStrokeWidth(BLUE_CIRCLE_BORDER_WIDTH);

  redCirclePaint.setColor(Color.RED);
  redCirclePaint.setAntiAlias(true);
  redCirclePaint.setStyle(Paint.Style.STROKE);
  redCirclePaint.setStrokeWidth(INSIDER_RED_CIRCLE_BORDER_WIDTH);

  whiteCirclePaint.setColor(Color.WHITE);
  whiteCirclePaint.setAntiAlias(true);
  whiteCirclePaint.setStyle(Paint.Style.STROKE);
  whiteCirclePaint.setStrokeWidth(WHITE_CIRCLE_BORDER_WIDTH);

 }

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  super.onMeasure(widthMeasureSpec, heightMeasureSpec);
  int width = MeasureSpec.getSize(widthMeasureSpec);
  int height = MeasureSpec.getSize(heightMeasureSpec);
  centerX = width / 2;
  centerY = height / 2;
  //获取直径和半径以及中心带你坐标方便后面的计算
  minLength = Math.min(width, height);
  radius = minLength / 2;

 }

 /**
  * 公开方法设置当前的状态值
  * @param state
  */
 public void setState(int state) {
  this.curState = state;
 }

 @Override
 protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  canvas.drawColor(Color.TRANSPARENT);
  switch (curState) {
   case STATE_READY:
    drawWhiteCircle(canvas);
    drawInsiderRedCircle(canvas);
    drawOutsiderRedCircle(canvas);
    break;
   case STATE_SCANING:
    drawWhiteCircle(canvas);
    drawBlueCircle(canvas);
    drawInsiderRedCircle(canvas);
    drawOutsiderRedCircle(canvas);
    drawScaner(canvas);
    break;
   case STATE_SUCCESS:
    drawWhiteCircle(canvas);
    drawInsiderRedCircle(canvas);
    break;
  }
  updateValues();
  invalidate();
 }

 private int blueStartAngle = 0;//蓝色圆圈的开始角度
 private int blueCircleSpace = BLUE_CIRCLE_BORDER_WIDTH;//蓝色弧距离最短边的距离用于计算自身的半径用
 private static final int BLUE_CIRCLE_SWEP_ANGLE = 20;//蓝色弧扫过的角度

 /**
  * 绘制蓝色弧
  * @param canvas
  */
 private void drawBlueCircle(Canvas canvas) {
  canvas.drawArc(centerX - radius + blueCircleSpace, blueCircleSpace, centerX + radius - blueCircleSpace, minLength - blueCircleSpace, blueStartAngle, BLUE_CIRCLE_SWEP_ANGLE, false, blueCirclePaint);
  canvas.drawArc(centerX - radius + blueCircleSpace, blueCircleSpace, centerX + radius - blueCircleSpace, minLength - blueCircleSpace, blueStartAngle + 180, BLUE_CIRCLE_SWEP_ANGLE, false, blueCirclePaint);
 }

 /**
  * 根据当前的状态来更改变量达到动画的效果
  */
 private void updateValues() {
  switch (curState) {
   case STATE_READY:
    if (insideRedCircleSpace >= BLUE_CIRCLE_BORDER_WIDTH + INSIDER_RED_CIRCLE_BORDER_WIDTH+ OUTSIDER_CIRCLE_BORDER_WIDTH) {
     insideRedCircleSpace -= 2;
    }
    whiteStartAngle = 5 / 2;
    outsiderRedCircleStartAndle = -OUTSIDER_RED_CIRCLE_SWEP_ANGLE / 2;
    break;
   case STATE_SCANING:
    if (insideRedCircleSpace >= BLUE_CIRCLE_BORDER_WIDTH + INSIDER_RED_CIRCLE_BORDER_WIDTH+ OUTSIDER_CIRCLE_BORDER_WIDTH) {
     insideRedCircleSpace -= 2;
    }
    blueStartAngle += 4;
    outsiderRedCircleStartAndle += 2;
    if (is2Max) {
     if (whiteStartAngle == 30) {
      is2Max = false;
     } else {
      whiteStartAngle++;
     }
    } else {
     if (whiteStartAngle == -30) {
      is2Max = true;
     } else {
      whiteStartAngle--;
     }
    }
    scanerY += 6;
    if (scanerY > minLength) {
     scanerY = 0;
    }
    break;
   case STATE_SUCCESS:
    whiteStartAngle = 5 / 2;
    if (insideRedCircleSpace < whiteCircleSpace + INSIDER_RED_CIRCLE_BORDER_WIDTH) {
     insideRedCircleSpace += 2;
    }
    break;
  }
 }

 private int insideRedCircleSpace = BLUE_CIRCLE_BORDER_WIDTH + INSIDER_RED_CIRCLE_BORDER_WIDTH + OUTSIDER_CIRCLE_BORDER_WIDTH;
 private int outsiderRedCircleSpace = BLUE_CIRCLE_BORDER_WIDTH + INSIDER_RED_CIRCLE_BORDER_WIDTH + OUTSIDER_CIRCLE_BORDER_WIDTH / 2;
 private static final int OUTSIDER_RED_CIRCLE_SWEP_ANGLE = 30;
 private int outsiderRedCircleStartAndle = -OUTSIDER_RED_CIRCLE_SWEP_ANGLE / 2;

 /**
  * 绘制内部的红色圆圈
  * @param canvas
  */
 private void drawInsiderRedCircle(Canvas canvas) {
  canvas.drawCircle(centerX, centerY, radius - insideRedCircleSpace, redCirclePaint);
 }

 /**
  * 绘制外部红色的两个弧
  * @param canvas
  */
 private void drawOutsiderRedCircle(Canvas canvas) {
  canvas.drawArc(centerX - radius + outsiderRedCircleSpace, outsiderRedCircleSpace, centerX + radius - outsiderRedCircleSpace, minLength - outsiderRedCircleSpace, outsiderRedCircleStartAndle, OUTSIDER_RED_CIRCLE_SWEP_ANGLE, false, redCirclePaint);
  canvas.drawArc(centerX - radius + outsiderRedCircleSpace, outsiderRedCircleSpace, centerX + radius - outsiderRedCircleSpace, minLength - outsiderRedCircleSpace, outsiderRedCircleStartAndle + 180, OUTSIDER_RED_CIRCLE_SWEP_ANGLE, false, redCirclePaint);
 }

 private int whiteStartAngle = 0;
 private static final int WHITE_CIRCLE_SWEP_ANGLE = 85;
 private int whiteCircleSpace = BLUE_CIRCLE_BORDER_WIDTH + INSIDER_RED_CIRCLE_BORDER_WIDTH + OUTSIDER_CIRCLE_BORDER_WIDTH + WHITE_CIRCLE_BORDER_WIDTH;
 private RectF whiteCircleRect;
 private boolean is2Max = true;

 /**
  * 绘制白色的弧
  * @param canvas
  */
 private void drawWhiteCircle(Canvas canvas) {
  if (whiteCircleRect == null) {
   whiteCircleRect = new RectF(centerX - radius + whiteCircleSpace, whiteCircleSpace, centerX + radius - whiteCircleSpace, minLength - whiteCircleSpace);
  }

  canvas.drawArc(whiteCircleRect, whiteStartAngle, WHITE_CIRCLE_SWEP_ANGLE, false, whiteCirclePaint);
  canvas.drawArc(whiteCircleRect, whiteStartAngle + 90, WHITE_CIRCLE_SWEP_ANGLE, false, whiteCirclePaint);
  canvas.drawArc(whiteCircleRect, whiteStartAngle + 180, WHITE_CIRCLE_SWEP_ANGLE, false, whiteCirclePaint);
  canvas.drawArc(whiteCircleRect, whiteStartAngle + 270, WHITE_CIRCLE_SWEP_ANGLE, false, whiteCirclePaint);

 }

 private int scanerY = 0;

 /**
  * 绘制扫描图片
  * @param canvas
  */
 private void drawScaner(Canvas canvas) {

  int p1, p2, hw;
  if (scanerY >= radius) {
   p1 = (scanerY - radius) * (scanerY - radius);
  } else {
   p1 = (radius - scanerY) * (radius - scanerY);
  }
  p2 = radius * radius;
  hw = (int) Math.sqrt(p2 - p1);

  Rect rect = new Rect(centerX - hw, scanerY - 10, centerX + hw, scanerY + 10);
  canvas.drawBitmap(scanerbitmap, null, rect, null);

 }
}

下面是我偶读github地址

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