Android 绘制饼图

抛物线大神绘制相关的文章https://hencoder.com/ui-1-1/
先放效果图：

未标题-2.gif

绘制思路：
绘制饼图，考虑到各饼块之间有间隔，先定义基准圆心，圆半径，普通饼图偏移量以及点击状态饼图偏移量。

private static final float COMMONPIARCSPACE = 2;//普通饼图偏移量
private static final float PUSHOUTPIARCSPACE = 15;//点击状态饼图偏移量
private static final Point point = new Point(300,300);//圆心
private static final float circleR = 200;//圆半径

饼图圆心的位置与饼图的中线的夹角相关,举个例子：

image.png

当饼图弧度为 PI/2时，中线夹角为 PI/4，圆心从O(0,0)移动4个偏移量的位置为O(2,2)，即圆心分别在X轴及Y轴移动2个位置。上代码：

    /**
 * 绘制每个百分比饼图
 * @param canvas
 * @param startDegree 圆弧开始的角度
 * @param degree 圆弧划过的角度
 * @param color 饼图颜色
 * @param drawDeltaValue 饼图与基准圆心的偏移量
 */
private void commonDrawPi(Canvas canvas,double startDegree,float degree,String color,float drawDeltaValue){
    double averageDegree = startDegree + degree/2;
    double deltaX = Math.cos(Math.toRadians(averageDegree));
    double deltaY = Math.sin(Math.toRadians(averageDegree));

    BigDecimal bigDeltaX = new BigDecimal(String.valueOf(deltaX)).setScale(16, BigDecimal.ROUND_HALF_UP);
    BigDecimal bigDeltaY = new BigDecimal(String.valueOf(deltaY)).setScale(16, BigDecimal.ROUND_HALF_UP);

    float changeX = bigDeltaX.floatValue() * drawDeltaValue;
    float changeY = bigDeltaY.floatValue() * drawDeltaValue;

    RectF rectF = new RectF(point.x - circleR + changeX
            ,point.y - circleR + changeY
            ,point.x + circleR + changeX
            ,point.y + circleR + changeY);
    paint.setColor(Color.parseColor(color));
    canvas.drawArc(rectF,BigDecimal.valueOf(startDegree).floatValue(),degree,true,paint);
}

判断点击事件所在饼图位置。
判断点击位置，只需要判断点击位置与基准圆心的夹角以及点击位置与基准圆心间距离即可。

private ListpercentValueList = Arrays.asList(12.9,15.0,18.0,16.0,38.1);//饼图所占百分比

/**
 * 计算点击位置
 * @param event
 * @return
 */
private int caculateShowPie(MotionEvent event){
    float pointX = event.getX();
    float pointY = event.getY();

    float deltaX = pointX - point.x;
    float deltaY = pointY - point.y;

    double deltaXPow = Math.pow(BigDecimal.valueOf(deltaX).doubleValue(),2);
    double deltaYPow = Math.pow(BigDecimal.valueOf(deltaY).doubleValue(),2);
    double rPow = deltaXPow + deltaYPow;

    if (rPow < Math.pow(COMMONPIARCSPACE,2) || rPow > Math.pow(circleR + COMMONPIARCSPACE,2)){
        return PINOTSELECTED;
    }
    
    double sinA = deltaY/Math.sqrt(rPow); ;

    double positionDegree = Math.toDegrees(Math.asin(sinA));
    double scrennDegree = turnDegreeToScreenNormal(deltaX,deltaY,positionDegree);
    float degree = 0;
    double startDegree = 0;

    for (int i = 0;i < percentValueList.size(); i++) {
        Double percent = percentValueList.get(i);
        degree = (float) (percent * CIRCLETOTALDEGREE / 100);

        if (scrennDegree > startDegree && scrennDegree < startDegree + degree){
            return i;
        }
        startDegree += degree;
    }
    return PINOTSELECTED;
}

因为绘制饼图角度为顺时针方向，而反正弦得到的角度范围为[-PI/2,PI/2]。因此需要进行转换。

/**
 * 由于是采用的顺时针绘制饼图，所以需要将角度调整
 * 计算角度所属象限，返回正确角度
 * @param deltaX
 * @param deltaY
 * @param degree
 * @return
 */
private double turnDegreeToScreenNormal(float deltaX,float deltaY,double degree){
    if (deltaX > 0 && deltaY < 0){
        //第一象限
        return 360 + degree;
    }else if (deltaX < 0 && deltaY < 0){
        //第二象限
        return 180 - degree;
    }else if (deltaX < 0 && deltaY > 0){
        //第三象限
        return 90 + degree;
    }else{
        return degree;
    }
}

点击饼图动画，通过ValueAnimator改变偏移量达到动画效果。

ValueAnimator mValueAnimator;//点击动画
float mAnimatedValue = 0f;//动画瞬时值
float mTotalAnimateValue = 0f;//动画总值

public void startAnim() {
    stopAnim();
    startAnimation(0f, 1f, ANIMATIONTIME);
}

public void stopAnim() {
    if (mValueAnimator != null) {
        clearAnimation();
        mAnimatedValue = 0f;
        mValueAnimator.end();
    }
}

private ValueAnimator startAnimation(float startF, final float endF, long time){
    mValueAnimator = ValueAnimator.ofFloat(startF, endF);
    mTotalAnimateValue = endF - startF;
    mValueAnimator.setDuration(time);
    mValueAnimator.setInterpolator(new LinearInterpolator());
    mValueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator valueAnimator) {
            mAnimatedValue = (float) valueAnimator.getAnimatedValue();
            postInvalidate();
        }
    });

    if (!mValueAnimator.isRunning()) {
        mValueAnimator.start();

    }
    return mValueAnimator;
}

最后贴上完整代码：

public class DrawPieCircleView  extends View{
String[] mColors = {"#FF1EBC71","#FFF55253","#FFDAA520"
        ,"#FF90EE90","#FB4E09","#AA49D2CC","#00A0E9"};

private static final int ANIMATIONTIME = 300;
private static final float CIRCLETOTALDEGREE = 360.0f;

private static final float COMMONPIARCSPACE = 2;//普通饼图偏移量
private static final float PUSHOUTPIARCSPACE = 15;//点击状态饼图偏移量

private static final Point point = new Point(300,300);//圆心
private static final float circleR = 200;//圆半径

ValueAnimator mValueAnimator;//点击动画
float mAnimatedValue = 0f;//动画瞬时值
float mTotalAnimateValue = 0f;//动画总值

Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);

public static final int PINOTSELECTED = -1;
private int piSelectedPosition = PINOTSELECTED;//当前点击的饼图
private int prePiSelectedPosition = PINOTSELECTED;//上一个点击的饼图
private boolean hasPieNeedPushOutShow = false;//是否有点击状态的饼图需要展示

private ListpercentValueList = Arrays.asList(12.9,15.0,18.0,16.0,38.1);//饼图所占百分比

public void setPercentValueList(List percentValueList) {
    this.percentValueList = percentValueList;
    postInvalidate();
}

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

public DrawPieCircleView(Context context, AttributeSet attrs){
    super(context, attrs);
}

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

@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
    super.onLayout(changed, left, top, right, bottom);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
    if (event.getAction() == MotionEvent.ACTION_DOWN){
        int nowSelectedPi  = caculateShowPie(event);
        if (nowSelectedPi == PINOTSELECTED) return super.onTouchEvent(event);
        if (hasPieNeedPushOutShow){
            if (piSelectedPosition == nowSelectedPi){
                hasPieNeedPushOutShow = false;
                prePiSelectedPosition = piSelectedPosition;
                piSelectedPosition = PINOTSELECTED;
            }else{
                prePiSelectedPosition = piSelectedPosition;
                piSelectedPosition = nowSelectedPi;
            }
        }else{
            hasPieNeedPushOutShow = true;
            prePiSelectedPosition = PINOTSELECTED;
            piSelectedPosition = nowSelectedPi;
        }
        startAnim();
        return true;
    }

    return super.onTouchEvent(event);
}

/**
 * 计算点击位置
 * @param event
 * @return
 */
private int caculateShowPie(MotionEvent event){
    float pointX = event.getX();
    float pointY = event.getY();

    float deltaX = pointX - point.x;
    float deltaY = pointY - point.y;

    double deltaXPow = Math.pow(BigDecimal.valueOf(deltaX).doubleValue(),2);
    double deltaYPow = Math.pow(BigDecimal.valueOf(deltaY).doubleValue(),2);
    double rPow = deltaXPow + deltaYPow;

    if (rPow < Math.pow(COMMONPIARCSPACE,2) || rPow > Math.pow(circleR + COMMONPIARCSPACE,2)){
        return PINOTSELECTED;
    }

    double sinA = deltaY/Math.sqrt(rPow); ;

    double positionDegree = Math.toDegrees(Math.asin(sinA));
    double scrennDegree = turnDegreeToScreenNormal(deltaX,deltaY,positionDegree);
    float degree = 0;
    double startDegree = 0;

    for (int i = 0;i < percentValueList.size(); i++) {
        Double percent = percentValueList.get(i);
        degree = (float) (percent * CIRCLETOTALDEGREE / 100);

        if (scrennDegree > startDegree && scrennDegree < startDegree + degree){
            return i;
        }
        startDegree += degree;
    }
    return PINOTSELECTED;
}

/**
 * 由于是采用的顺时针绘制饼图，所以需要将角度调整
 * 计算角度所属象限，返回正确角度
 * @param deltaX
 * @param deltaY
 * @param degree
 * @return
 */
private double turnDegreeToScreenNormal(float deltaX,float deltaY,double degree){
    if (deltaX > 0 && deltaY < 0){
        //第一象限
        return 360 + degree;
    }else if (deltaX < 0 && deltaY < 0){
        //第二象限
        return 180 - degree;
    }else if (deltaX < 0 && deltaY > 0){
        //第三象限
        return 90 + degree;
    }else{
        return degree;
    }
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    float degree = 0;
    double startDegree = 0;
    double totalDegre = CIRCLETOTALDEGREE;

    for (int i = 0;i < percentValueList.size(); i++){
        Double percent = percentValueList.get(i);
        degree = (float)(percent*totalDegre/100);
        float animatDistance = 0;
        if ( i != prePiSelectedPosition  && i != piSelectedPosition){
            animatDistance = COMMONPIARCSPACE;
        }else{
            if (i == prePiSelectedPosition){
                animatDistance = (mTotalAnimateValue - mAnimatedValue)/mTotalAnimateValue * (PUSHOUTPIARCSPACE - COMMONPIARCSPACE) + COMMONPIARCSPACE;
            }else{
                animatDistance = mAnimatedValue/mTotalAnimateValue * (PUSHOUTPIARCSPACE - COMMONPIARCSPACE) + COMMONPIARCSPACE;
            }
        }

        commonDrawPi(canvas,startDegree,degree,mColors[i],animatDistance);
        startDegree += degree;
    }

    if (mAnimatedValue == 1f){
        if (hasPieNeedPushOutShow) {
            prePiSelectedPosition = PINOTSELECTED;
        } else {
            prePiSelectedPosition = PINOTSELECTED;
            piSelectedPosition = PINOTSELECTED;
        }
    }
}

/**
 * 绘制每个百分比饼图
 * @param canvas
 * @param startDegree 圆弧开始的角度
 * @param degree 圆弧划过的角度
 * @param color 饼图颜色
 * @param drawDeltaValue 饼图与基准圆心的偏移量
 */
private void commonDrawPi(Canvas canvas,double startDegree,float degree,String color,float drawDeltaValue){
    double averageDegree = startDegree + degree/2;
    double deltaX = Math.cos(Math.toRadians(averageDegree));
    double deltaY = Math.sin(Math.toRadians(averageDegree));

    BigDecimal bigDeltaX = new BigDecimal(String.valueOf(deltaX)).setScale(16, BigDecimal.ROUND_HALF_UP);
    BigDecimal bigDeltaY = new BigDecimal(String.valueOf(deltaY)).setScale(16, BigDecimal.ROUND_HALF_UP);

    float changeX = bigDeltaX.floatValue() * drawDeltaValue;
    float changeY = bigDeltaY.floatValue() * drawDeltaValue;

    RectF rectF = new RectF(point.x - circleR + changeX
            ,point.y - circleR + changeY
            ,point.x + circleR + changeX
            ,point.y + circleR + changeY);
    paint.setColor(Color.parseColor(color));
    canvas.drawArc(rectF,BigDecimal.valueOf(startDegree).floatValue(),degree,true,paint);
}

public void startAnim() {
    stopAnim();
    startAnimation(0f, 1f, ANIMATIONTIME);
}

public void stopAnim() {
    if (mValueAnimator != null) {
        clearAnimation();
        mAnimatedValue = 0f;
        mValueAnimator.end();
    }
}

private ValueAnimator startAnimation(float startF, final float endF, long time){
    mValueAnimator = ValueAnimator.ofFloat(startF, endF);
    mTotalAnimateValue = endF - startF;
    mValueAnimator.setDuration(time);
    mValueAnimator.setInterpolator(new LinearInterpolator());
    mValueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator valueAnimator) {
            mAnimatedValue = (float) valueAnimator.getAnimatedValue();
            postInvalidate();
        }
    });

    if (!mValueAnimator.isRunning()) {
        mValueAnimator.start();

    }
    return mValueAnimator;
  }
}

Android 绘制饼图

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