Android自定义View仿支付宝芝麻信用分仪表盘

先看下iOS的芝麻信用分截图

这是我做的效果，还是有点差距的

支付宝9.9版本芝麻信用分的实现

首先初始化各种画笔,默认的size，padding，小圆点.

(因为实在找不到原版芝麻信用的带点模糊效果的小圆点,所以只好用这个代替)

//View的默认大小
defaultSize = dp2px(250);
//默认Padding大小
arcDistance = dp2px(14);

//外层圆环画笔
mMiddleArcPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mMiddleArcPaint.setStrokeWidth(8);
mMiddleArcPaint.setColor(Color.WHITE);
mMiddleArcPaint.setStyle(Paint.Style.STROKE);
mMiddleArcPaint.setAlpha(80);

//内层圆环画笔
mInnerArcPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mInnerArcPaint.setStrokeWidth(30);
mInnerArcPaint.setColor(Color.WHITE);
mInnerArcPaint.setAlpha(80);
mInnerArcPaint.setStyle(Paint.Style.STROKE);

//正中间字体画笔
mTextPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mTextPaint.setColor(Color.WHITE);
mTextPaint.setTextAlign(Paint.Align.CENTER);

//圆环大刻度画笔
mCalibrationPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mCalibrationPaint.setStrokeWidth(4);
mCalibrationPaint.setStyle(Paint.Style.STROKE);
mCalibrationPaint.setColor(Color.WHITE);
mCalibrationPaint.setAlpha(120);

//圆环小刻度画笔
mSmallCalibrationPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mSmallCalibrationPaint.setStrokeWidth(1);
mSmallCalibrationPaint.setStyle(Paint.Style.STROKE);
mSmallCalibrationPaint.setColor(Color.WHITE);
mSmallCalibrationPaint.setAlpha(130);

//圆环刻度文本画笔
mCalibrationTextPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mCalibrationTextPaint.setTextSize(30);
mCalibrationTextPaint.setColor(Color.WHITE);

//外层进度画笔
mArcProgressPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mArcProgressPaint.setStrokeWidth(8);
mArcProgressPaint.setColor(Color.WHITE);
mArcProgressPaint.setStyle(Paint.Style.STROKE);
mArcProgressPaint.setStrokeCap(Paint.Cap.ROUND);

//外层圆环上小圆点Bitmap画笔
mBitmapPaint = new Paint();
mBitmapPaint.setStyle(Paint.Style.FILL);
mBitmapPaint.setAntiAlias(true);

//初始化小圆点图片
bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_circle);
//当前点的实际位置
pos = new float[2];
//当前点的tangent值
tan = new float[2];
matrix = new Matrix();

代码很简单,就是各种初始化,往下看.

View的测量,主要在给设置warp_content时候给定一个默认宽高值.

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec){
setMeasuredDimension(resolveMeasure(widthMeasureSpec, defaultSize),
  resolveMeasure(heightMeasureSpec, defaultSize));}

//根据传入的值进行测量
public int resolveMeasure(int measureSpec, int defaultSize){
int result = 0;
int specSize = MeasureSpec.getSize(measureSpec);
switch (MeasureSpec.getMode(measureSpec))
 {
 case MeasureSpec.UNSPECIFIED:
 result = defaultSize;
 break;
 case MeasureSpec.AT_MOST:
 //设置warp_content时设置默认值
 result = Math.min(specSize, defaultSize);
 break;
 case MeasureSpec.EXACTLY:
 //设置math_parent 和设置了固定宽高值
 break;
 default:
 result = defaultSize;
 }
 return result;}

然后确定View的宽高后的回调方法.

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh){
 super.onSizeChanged(w, h, oldw, oldh);
 width = w;
 height = h;
 radius = width / 2;
//外层圆环矩形
 mMiddleRect = new RectF(defaultPadding, defaultPadding,width - defaultPadding, height - defaultPadding);
//内层圆环矩形
 mInnerRect = new RectF(defaultPadding + arcDistance, defaultPadding + arcDistance,width - defaultPadding - arcDistance, height - defaultPadding - arcDistance);
// 外层进度矩形
 mMiddleProgressRect = new RectF(defaultPadding, defaultPadding,width - defaultPadding, height - defaultPadding);
}

这里就是初始化圆弧所需要的矩形实现,下边开始进行重点,绘制，

绘制外层的圆弧,很简单, 圆弧的起始角度,角度.

private void drawMiddleArc(Canvas canvas){
canvas.drawArc(mMiddleRect, mStartAngle, mEndAngle, false, mMiddleArcPaint);
}

绘制内层圆弧

private void drawInnerArc(Canvas canvas){
 canvas.drawArc(mInnerRect, mStartAngle, mEndAngle, false, mInnerArcPaint);
}

绘制内层圆弧上的小刻度,画布旋转到圆弧左下角起点,计算出每条刻度线的起始点后,整个圆弧是210度,

每6角度绘制一条刻度线.

private void drawSmallCalibration(Canvas canvas){
 //旋转画布
 canvas.save();
 canvas.rotate(-105, radius, radius);
 //计算刻度线的起点结束点
 int startDst = (int) (defaultPadding + arcDistance - mInnerArcPaint.getStrokeWidth() / 2 - 1);
 int endDst = (int) (startDst + mInnerArcPaint.getStrokeWidth());
 for (int i = 0; i <= 35; i++) {
 //每旋转6度绘制一个小刻度
 canvas.drawLine(radius, startDst, radius, endDst, mSmallCalibrationPaint);
 canvas.rotate(6, radius, radius);
}
canvas.restore();
}

绘制内层圆弧上的大刻度,350, 550, 600,650, 700, 950，对应的信用分值,

一样旋转画布,计算刻度线的起始点,计算出每次旋转的角度,每35度旋转一次,依次绘制对应的大刻度线,

然后绘制对应的文本内容,使用paint的measureText方法测量出文本的长度,依次绘制对应的文本内容.

private void drawCalibrationAndText(Canvas canvas){
 //旋转画布进行绘制对应的刻度
 canvas.save();
 canvas.rotate(-105, radius, radius);
 //计算刻度线的起点结束点
 int startDst = (int) (defaultPadding + arcDistance - mInnerArcPaint.getStrokeWidth() / 2 - 1);
 int endDst = (int) (startDst + mInnerArcPaint.getStrokeWidth());
 //刻度旋转的角度
 int rotateAngle = 210 / 10;
 for (int i = 1; i < 12; i++) {
 if (i % 2 != 0)
 {
 canvas.drawLine(radius, startDst, radius, endDst, mCalibrationPaint);
 }
 // 测量文本的长度
float textLen = mCalibrationTextPaint.measureText(sesameStr[i - 1]);
canvas.drawText(sesameStr[i - 1], radius - textLen / 2, endDst + 40, mCalibrationTextPaint);
canvas.rotate(rotateAngle, radius, radius);
}
canvas.restore();}

绘制中间的信用分值,信用等级,评估时间等文本,这个比较简单,直接drawText,依次高低排列绘制即可.

private void drawCenterText(Canvas canvas){
 //绘制Logo
 mTextPaint.setTextSize(30);
 canvas.drawText("BETA", radius, radius - 130, mTextPaint);
 //绘制信用分数
 mTextPaint.setTextSize(200);
 mTextPaint.setStyle(Paint.Style.STROKE);
 canvas.drawText(String.valueOf(mMinNum), radius, radius + 70, mTextPaint);
 //绘制信用级别
 mTextPaint.setTextSize(80);
 canvas.drawText(sesameLevel, radius, radius + 160, mTextPaint);
 //绘制评估时间
 mTextPaint.setTextSize(30);
 canvas.drawText(evaluationTime, radius, radius + 205, mTextPaint);
}

绘制最外层的进度,这里使用的Path添加要绘制的圆弧,因为需要去不断的计算坐标点,主要用到了PathMeasure这个类,将绘制的圆弧加入到path中,

当前点的实际位置

private float[] pos;

当前的tangent值

private float[] tan;

获取路径的终点的正切值和坐标，然后根据坐标点绘制小圆点

PathMeasure pathMeasure = new PathMeasure(path, false);
pathMeasure.getPosTan(pathMeasure.getLength() * 1, pos, tan);

private void drawRingProgress(Canvas canvas){ 

 Path path = new Path();
 path.addArc(mMiddleProgressRect, mStartAngle, mCurrentAngle);
 PathMeasure pathMeasure = new PathMeasure(path, false);
 pathMeasure.getPosTan(pathMeasure.getLength() * 1, pos, tan);
 matrix.reset();
 matrix.postTranslate(pos[0] - bitmap.getWidth() / 2, pos[1] - bitmap.getHeight() / 2);
 canvas.drawPath(path, mArcProgressPaint);
 //起始角度不为0时候才进行绘制小圆点
 if (mCurrentAngle == 0)
  return;
 canvas.drawBitmap(bitmap, matrix, mBitmapPaint);
 mBitmapPaint.setColor(Color.WHITE);
 canvas.drawCircle(pos[0], pos[1], 8, mBitmapPaint);
}

好了,到这里所有绘制完毕了,接下来让圆弧进度条动起来吧,使用ValueAnimator,进度条动画定义了圆弧进度条的开始角度mCurrentAngle,圆弧角度mTotalAngle,数值动画定义了初始化minNum=0，maxNum根据传入的数值进行计算.

public void startAnim(){
 ValueAnimator mAngleAnim = ValueAnimator.ofFloat(mCurrentAngle, mTotalAngle);
 mAngleAnim.setInterpolator(new AccelerateDecelerateInterpolator());
 mAngleAnim.setDuration(3000);
 mAngleAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener(){
 @Override
 public void onAnimationUpdate(ValueAnimator valueAnimator){
 mCurrentAngle = (float) valueAnimator.getAnimatedValue();
 postInvalidate();  

}
});
 mAngleAnim.start(); 

 ValueAnimator mNumAnim = ValueAnimator.ofInt(mMinNum, mMaxNum);
 mNumAnim.setDuration(3000);
 mNumAnim.setInterpolator(new LinearInterpolator());
 mNumAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
 @Override
 public void onAnimationUpdate(ValueAnimator valueAnimator){
 mMinNum = (int) valueAnimator.getAnimatedValue();
 postInvalidate();  

}
});
 mNumAnim.start();}

最后根据传入的信用分值计算圆弧进度条所到的角度.

public void setSesameValues(int values){
 if (values <= 350){
 mMaxNum = values;
 mTotalAngle = 0f;
 sesameLevel = "信用较差";
 evaluationTime = "评估时间:" + getCurrentTime();
 } else if (values <= 550){
 mMaxNum = values;
 mTotalAngle = (values - 350) * 80 / 400f + 2;
 sesameLevel = "信用较差";
 evaluationTime = "评估时间:" + getCurrentTime();
 } else if (values <= 700)
 {
 mMaxNum = values;
 if (values > 550 && values <= 600){
 sesameLevel = "信用中等";
 } else if (values > 600 && values <= 650){
 sesameLevel = "信用良好";
 } else {
 sesameLevel = "信用优秀";
 }
 mTotalAngle = (values - 550) * 120 / 150f + 43;
 evaluationTime = "评估时间:" + getCurrentTime();
 } else if (values <= 950){
 mMaxNum = values;
 mTotalAngle = (values - 700) * 40 / 250f + 170;
 sesameLevel = "信用极好";
 evaluationTime = "评估时间:" + getCurrentTime();
 } else{
 mTotalAngle = 240f;
 }
 startAnim();
}

总结

这篇文章只分析了新版的实现过程，旧版的的实现思路也差不多，代码也不复杂。希望这篇文章对大家开发Android能有所帮助，如果有疑问可以留言交流。