然后准备实现一波，做之前在网上找了很久，并没有相似的效果，所以自己做了一个，已经上传到我的代码库里：

欢迎小伙伴们的start或者requests

下面简单说一下实现过程：

1.首先要讲传入的数据数组进行排序，因为是2d平面模拟3d，所以弧形的绘制要由内到外才不会出现错位的情况：

//计算出绘制顺序

private void computationOrder(){

ArrayList tempOrderList = new ArrayList<>();

leftAngle = 0;

rightAngle = 0;

for (int i = 0; i < max; i++) {

Collections.sort(mEntries, new MyCompare());

Entry tempEntry = mEntries.get(0);

float halfAngle = tempEntry.percent / 2;

/*

1.算法，先绘制最大的一块，居中

2.剩下的 优先记录左边和右边的坐标值

3.优先添加不会溢出的

*/

if (i == 0) {

leftAngle = 270f - halfAngle;

rightAngle = 270f + halfAngle;

if (rightAngle >= 360) {

rightAngle -= 360f;

}

tempEntry.tag = CENTER;

tempEntry.startAngle = leftAngle;

mEntries.remove(0);

} else {

//1.找到当前小的边

if (getDistanceToCenter(leftAngle, LEFT) > getDistanceToCenter(rightAngle, RIGHT)) {

//左边比右边大，取右边

tempEntry = getNextAngle(getDistanceToCenter(rightAngle, RIGHT));

tempEntry.tag = RIGHT;

rightAngle += tempEntry.percent;

if (rightAngle >= 360) {

rightAngle -= 360f;

}

tempEntry.startAngle = rightAngle;

} else {

//右边比左边大，取左边

tempEntry = getNextAngle(getDistanceToCenter(leftAngle, LEFT));

tempEntry.tag = LEFT;

leftAngle -= tempEntry.percent;

tempEntry.startAngle = leftAngle;

}

}

tempOrderList.add(tempEntry);

}

mEntrySourceList = tempOrderList;

}

2.然后是绘制部分，首先根据排列的顺序进行绘制，依次绘制各个弧形段，然后画轮廓线：

private void drawCylinder(Canvas canvas, Entry tempEntry, int thickness,boolean ifChangeThick){

mainPaint.setStyle(Paint.Style.FILL);

//绘制各个弧度

int perThickness =ifChangeThick? (int) ((tempEntry.percent / 360f) * thickness * (max * 0.5f)) : thickness;

float drawTempStartAngle = 0f;

RectF tempRectF;

float lineStartX = 0f;

float lineStartY = 0f;

float lineEndX = 0f;

float lineEndY = 0f;

float oX = centerX;

float oY = (area2DHeight + area3DHight) / 2;

float R = centerX;

//y轴2d3d缩放比例

float bilv = ((float) (area3DHight - area2DHeight)) / ((float) area2DHeight);

for (int j = 0; j <= perThickness; j++) {

tempRectF = new RectF(0, area2DHeight - j, area2DWidth, area3DHight - j);

switch (tempEntry.tag) {

case CENTER:

drawTempStartAngle = tempEntry.startAngle;

lineStartX = oX;

lineEndX = oX;

lineStartY = (area2DHeight + area3DHight) / 2;

lineEndY = oY - j;

break;

case LEFT:

drawTempStartAngle = tempEntry.startAngle;

/*

左边夹角tempAngle 0< tempAngle < 180

90

*/

if (drawTempStartAngle <= 180) {

//startAngle 90-180

lineStartX = oX - (float) (R * Math.sin(Math.toRadians(drawTempStartAngle - 90f)));

lineEndX = lineStartX;

lineStartY = oY + (float) (bilv * R * Math.cos(Math.toRadians(drawTempStartAngle - 90f)));

lineEndY = lineStartY - j;

} else {

//startAngle 180-270

lineStartX = oX - (float) (R * Math.cos(Math.toRadians(drawTempStartAngle - 180f)));

lineEndX = lineStartX;

lineStartY = oY - (float) (bilv * R * Math.sin(Math.toRadians(drawTempStartAngle - 180f)));

lineEndY = lineStartY - j;

}

break;

case RIGHT:

drawTempStartAngle = tempEntry.startAngle - tempEntry.percent;

/*

右边夹角tempAngle 0< tempAngle < 180

90

*/

if (drawTempStartAngle <= 360) {

//startAngle 270-360

lineStartX = oX + (float) (R * Math.cos(Math.toRadians(360f - drawTempStartAngle - tempEntry.percent)));

lineEndX = lineStartX;

lineStartY = oY - (float) (bilv * R * Math.sin(Math.toRadians(360f - drawTempStartAngle - tempEntry.percent)));

lineEndY = lineStartY - j;

} else {

//startAngle 0-90

lineStartX = oX + (float) (R * Math.cos(Math.toRadians(drawTempStartAngle)));

lineEndX = lineStartX;

lineStartY = oY - (float) (bilv * R * Math.sin(Math.toRadians(drawTempStartAngle)));

lineEndY = lineStartY - j;

}

break;

}

//弧形

mainPaint.setColor(tempEntry.color);

canvas.drawArc(tempRectF, drawTempStartAngle, tempEntry.percent, true, mainPaint);

if (j == perThickness) {

drawTopLine(canvas, tempRectF, drawTempStartAngle, tempEntry.percent);

}

//竖直线

mainPaint.setColor(Color.WHITE);

if (tempEntry.tag == CENTER) {

canvas.drawLine(lineStartX, lineStartY,

lineEndX, lineEndY,

mainPaint);

//还需要画左右两边的竖直线

float xOffset = (float) (R * Math.sin(Math.toRadians(tempEntry.percent / 2)));

float yOffset = (float) (bilv * R * Math.cos(Math.toRadians(tempEntry.percent / 2)));

canvas.drawLine(

oX - xOffset,

oY - yOffset,

oX - xOffset,

oY - yOffset - j,

mainPaint);

canvas.drawLine(

oX + xOffset,

oY - yOffset,

oX + xOffset,

oY - yOffset - j,

mainPaint);

} else {

canvas.drawLine(lineStartX, lineStartY,

lineEndX, lineEndY,

mainPaint);

}

}

}

3.两种不同的动画效果在ondraw里面分别进行判断：

@SuppressLint("DrawAllocation")

@Override

protected void onDraw(Canvas canvas){

super.onDraw(canvas);

switch (ANIM_STATE) {

case ANIM_STATE_ALL:

for (int i = 0; i < mEntrySourceList.size(); i++) {

Entry tempEntry = mEntrySourceList.get(i);

drawCylinder(canvas, tempEntry, thickness,true);

}

break;

case ANIM_STATE_SINGLE:

for (int i = 0; i < mEntrySourceList.size(); i++) {

Entry tempEntry = mEntrySourceList.get(i);

drawCylinder(canvas, tempEntry, 1,false);

}

for (int i = 0; i < singleAnimIndex; i++) {

if (i < mEntrySourceList.size()) {

Entry tempEntry = mEntrySourceList.get(i);

int tempThickNess = singleAnimValue - (i + 1) * 100;

LogUtils.INSTANCE.d("tempThickNess: " + tempThickNess);

tempThickNess = (int) ((tempEntry.percent / 360f) * tempThickNess * (max * 0.33f));

drawCylinder(canvas, tempEntry, tempThickNess,false);

}

}

break;

case ANIM_STATE_CHANGGE:

break;

}

}

至此就介绍得差不多了，具体的代码里面都有注释，希望喜欢的小伙伴们点个赞，有问题可以留言。