今天讲图表统计中比较常用的一个，像支付宝的月账单啥的，都是用圆饼图来做数据统计的，先看一下我最终实现的效果图：
image.png
该效果实际上是两个实心圆叠加后的效果。
image.png
image.png
《一》View实现思路分析：
（1）根据占比集合数据，计算所需绘制的角度，动态设置画笔颜色，drawArc()绘制外圆弧
（2）drawCircle()绘制内圆
（3）确定每块圆饼的小白点的位置
（4）绘制白点的沿线和占比文字
《二》具体实现：
（1）绘制不同颜色的圆饼
for (int i = 0; i < mRateList.size(); i++) {
mPaint.setStyle(Paint.Style.FILL);
mPaint.setColor(mColorList.get(i));
// Log.e("TAG", "startAngle=" + startAngle + "--sweepAngle=" + ((int) (mRateList.get(i) * (360)) - offset));
canvas.drawArc(rectF, startAngle, (int) (mRateList.get(i) * (360)) , true, mPaint);
startAngle = startAngle + (int) (mRateList.get(i) * 360);
}
(2)绘制内圆
mPaint.setColor(ContextCompat.getColor(mContext, R.color.color_081638));
canvas.drawCircle(radius + centerPointRadius + (xOffset + yOffset + textRect.width()), radius + centerPointRadius + (xOffset + yOffset + textRect.height()), radius / 1.5f, mPaint);
(3)确定每块圆饼的小白点的位置，通过每段圆饼的起始角度确定该段圆弧的中心点位置。
private void dealPoint(RectF rectF, float startAngle, float endAngle, List pointList) {
Path path = new Path();
//通过Path类画一个90度（180—270）的内切圆弧路径
path.addArc(rectF, startAngle, endAngle);
PathMeasure measure = new PathMeasure(path, false);
// Log.e("路径的测量长度:", "" + measure.getLength());
float[] coords = new float[]{0f, 0f};
//利用PathMeasure分别测量出各个点的坐标值coords
int divisor = 1;
measure.getPosTan(measure.getLength() / divisor, coords, null);
// Log.e("coords:", "x轴:" + coords[0] + " -- y轴:" + coords[1]);
float x = coords[0];
float y = coords[1];
Point point = new Point(Math.round(x), Math.round(y));
pointList.add(point);
}
（4）绘制以白点为起点的折线和占比文字。有个细节需要注意一下，绘制折线和比例文字时，每部分沿线和文字的绘制规则不一样，我是按下面的规则处理的：将圆分为四部分，每块区分显示。
image.png
//折线横向长度
private int xOffset;
//折线偏Y方向长度
private int yOffset;
private void dealRateText(Canvas canvas, Point point, int position, List pointList) {
if (position == 0) {
lastPoint = pointList.get(0);
} else {
lastPoint = pointList.get(position - 1);
}
float[] floats = new float[8];
floats[0] = point.x;
floats[1] = point.y;
//右半圆
if (point.x >= radius + centerPointRadius + (xOffset + yOffset + textRect.width())) {
mPaint.setTextAlign(Paint.Align.LEFT);
floats[6] = point.x + xOffset;
if (point.y <= radius + centerPointRadius + (xOffset + yOffset + textRect.height())) {
//右上角
floats[2] = point.x + yOffset;
floats[3] = point.y - yOffset;
floats[4] = point.x + yOffset;
floats[5] = point.y - yOffset;
floats[7] = point.y - yOffset;
} else {
//右下角
floats[2] = point.x + yOffset;
floats[3] = point.y + yOffset;
floats[4] = point.x + yOffset;
floats[5] = point.y + yOffset;
floats[7] = point.y + yOffset;
}
//左半圆
} else {
mPaint.setTextAlign(Paint.Align.RIGHT);
floats[6] = point.x - xOffset;
//防止相邻的圆饼绘制的文字重叠显示
if (point.y <= radius + centerPointRadius) {
//左上角
floats[2] = point.x - yOffset;
floats[3] = point.y - yOffset;
floats[4] = point.x - yOffset;
floats[5] = point.y - yOffset;
floats[7] = point.y - yOffset;
} else {
//左下角
floats[2] = point.x - yOffset;
floats[3] = point.y + yOffset;
floats[4] = point.x - yOffset;
floats[5] = point.y + yOffset;
floats[7] = point.y + yOffset;
}
}
//根据每块的颜色，绘制对应颜色的折线
// mPaint.setColor(mRes.getColor(colorList.get(position)));
mPaint.setColor(ContextCompat.getColor(mContext, R.color.color_b69b4f));
//画圆饼图每块边上的折线
canvas.drawLines(floats, mPaint);
mPaint.setStyle(Paint.Style.STROKE);
//绘制显示的文字,需要根据类型显示不同的文字
if (mRateList.size() > 0) {
//Y轴：+ textRect.height() / 2 ,相对沿线居中显示
canvas.drawText(getFormatPercentRate(mRateList.get(position) * 100) + "%", floats[6], floats[7] + textRect.height() / 2, mPaint);
}
}
完整代码：
package com.example.jojo.learn.customview;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PathMeasure;
import android.graphics.Point;
import android.graphics.Rect;
import android.graphics.RectF;
import android.support.annotation.Nullable;
import android.support.v4.content.ContextCompat;
import android.util.AttributeSet;
import android.view.View;
import com.example.jojo.learn.R;
import com.example.jojo.learn.utils.DP2PX;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.List;
/**
* Created by JoJo on 2018/8/6.
* wechat:18510829974
* description: 饼状图
*/
public class PieView extends View {
private Context mContext;
private Paint mPaint;
//每块占比的绘制的颜色
private List mColorList = new ArrayList<>();
//圆弧占比的集合
private List mRateList = new ArrayList<>();
//是否展示文字
private boolean isShowRateText;
//圆弧半径
private float radius;
private int startAngle = 0;
//不同色块之间是否需要空隙offset
private int offset = 0;
//圆弧中心点小圆点的圆心半径
private int centerPointRadius;
private float showRateSize;
private Rect textRect;
//折线横向长度
private int xOffset;
//折线偏Y方向长度
private int yOffset;
private float mChangeAngle;
private boolean isAnimation;
private int sign = 0;
public PieView(Context context) {
this(context, null);
}
public PieView(Context context, @Nullable AttributeSet attrs) {
this(context, attrs, 0);
}
public PieView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
mContext = context;
init();
initData();
}
private void initData() {
float[] rate = {30f, 40f, 15f, 15f};
int[] colors = {Color.RED, Color.BLUE, Color.YELLOW, Color.GRAY};
for (int i = 0; i < rate.length; i++) {
mRateList.add(rate[i] / 100);
mColorList.add(colors[i]);
}
textRect = new Rect();
if (mRateList.size() > 0) {
mPaint.getTextBounds((mRateList.get(0) + "%"), 0, (mRateList.get(0) + "%").length(), textRect);
}
}
private void init() {
radius = DP2PX.dip2px(mContext, 80);
centerPointRadius = DP2PX.dip2px(mContext, 2);
xOffset = DP2PX.dip2px(mContext, 20);
yOffset = DP2PX.dip2px(mContext, 5);
showRateSize = DP2PX.dip2px(mContext, 10);
mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mPaint.setColor(Color.RED);
mPaint.setAntiAlias(true);
mPaint.setStyle(Paint.Style.FILL);
mPaint.setTextSize(showRateSize);
if (mRateList.size() > 0) {
textRect = new Rect();
mPaint.getTextBounds((mRateList.get(0) + "%"), 0, (mRateList.get(0) + "%").length(), textRect);
}
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int heightSize = MeasureSpec.getSize(heightMeasureSpec);
if (heightMode == MeasureSpec.AT_MOST) {
//边沿线和文字所占的长度：(xOffset + yOffset + textRect.width())
heightSize = (int) (radius * 2) + 2 * centerPointRadius + getPaddingLeft() + getPaddingRight() + (xOffset + yOffset + textRect.height()) * 2;
}
if (widthMode == MeasureSpec.AT_MOST) {
widthSize = (int) (radius * 2) + 2 * centerPointRadius + getPaddingLeft() + getPaddingRight() + (xOffset + yOffset + textRect.width()) * 2;
}
//保存测量结果
setMeasuredDimension(widthSize, heightSize);
}
private int paintPosition;
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
//(1)绘制圆饼
RectF rectF = new RectF(0 + centerPointRadius + (xOffset + yOffset + textRect.width()), 0 + centerPointRadius + (xOffset + yOffset + textRect.height()), 2 * radius + centerPointRadius + (xOffset + yOffset + textRect.width()), 2 * radius + centerPointRadius + (xOffset + yOffset + textRect.height()));
List mPointList = new ArrayList<>();
for (int i = 0; i < mRateList.size(); i++) {
mPaint.setStyle(Paint.Style.FILL);
mPaint.setColor(mColorList.get(i));
// Log.e("TAG", "startAngle=" + startAngle + "--sweepAngle=" + ((int) (mRateList.get(i) * (360)) - offset));
canvas.drawArc(rectF, startAngle, (int) (mRateList.get(i) * (360)) - offset, true, mPaint);
//(2)处理每块圆饼弧的中心点，绘制折线，显示对应的文字
if (isShowRateText) {
dealPoint(rectF, startAngle, (mRateList.get(i) * 360 - offset) / 2, mPointList);
Point point = mPointList.get(i);
mPaint.setColor(Color.WHITE);//点的绘制的颜色
canvas.drawCircle(point.x, point.y, centerPointRadius, mPaint);
dealRateText(canvas, point, i, mPointList);
}
startAngle = startAngle + (int) (mRateList.get(i) * 360);
}
//(3)绘制内部中空的圆
mPaint.setColor(ContextCompat.getColor(mContext, R.color.color_081638));
mPaint.setStyle(Paint.Style.FILL);
canvas.drawCircle(radius + centerPointRadius + (xOffset + yOffset + textRect.width()), radius + centerPointRadius + (xOffset + yOffset + textRect.height()), radius / 1.5f, mPaint);
}
private Point lastPoint;
private void dealRateText(Canvas canvas, Point point, int position, List pointList) {
if (position == 0) {
lastPoint = pointList.get(0);
} else {
lastPoint = pointList.get(position - 1);
}
float[] floats = new float[8];
floats[0] = point.x;
floats[1] = point.y;
//右半圆
if (point.x >= radius + centerPointRadius + (xOffset + yOffset + textRect.width())) {
mPaint.setTextAlign(Paint.Align.LEFT);
floats[6] = point.x + xOffset;
//防止相邻的圆饼绘制的文字重叠显示
// if (lastPoint != null) {
// int absX = Math.abs(point.x - lastPoint.x);
// int absY = Math.abs(point.y - lastPoint.y);
// if (absX > 0 && absX < 20 && absY > 0 && absY < 20) {
// floats[6] = point.x + xOffset - textRect.width() / 2;
// Log.e("TAG", "右半圆");
// } else {
// floats[6] = point.x + xOffset;
// }
// } else {
// floats[6] = point.x + xOffset;
// }
if (point.y <= radius + centerPointRadius + (xOffset + yOffset + textRect.height())) {
//右上角
floats[2] = point.x + yOffset;
floats[3] = point.y - yOffset;
floats[4] = point.x + yOffset;
floats[5] = point.y - yOffset;
floats[7] = point.y - yOffset;
} else {
//右下角
floats[2] = point.x + yOffset;
floats[3] = point.y + yOffset;
floats[4] = point.x + yOffset;
floats[5] = point.y + yOffset;
floats[7] = point.y + yOffset;
}
//左半圆
} else {
mPaint.setTextAlign(Paint.Align.RIGHT);
floats[6] = point.x - xOffset;
//防止相邻的圆饼绘制的文字重叠显示
// if (lastPoint != null) {
// int absX = Math.abs(point.x - lastPoint.x);
// int absY = Math.abs(point.y - lastPoint.y);
// if (absX > 0 && absX < 20 && absY > 0 && absY < 20) {
// floats[6] = point.x - xOffset - textRect.width() / 2;
// Log.e("TAG", "左半圆");
// } else {
// floats[6] = point.x - xOffset;
// }
// } else {
// floats[6] = point.x - xOffset;
// }
if (point.y <= radius + centerPointRadius) {
//左上角
floats[2] = point.x - yOffset;
floats[3] = point.y - yOffset;
floats[4] = point.x - yOffset;
floats[5] = point.y - yOffset;
floats[7] = point.y - yOffset;
} else {
//左下角
floats[2] = point.x - yOffset;
floats[3] = point.y + yOffset;
floats[4] = point.x - yOffset;
floats[5] = point.y + yOffset;
floats[7] = point.y + yOffset;
}
}
//根据每块的颜色，绘制对应颜色的折线
// mPaint.setColor(mRes.getColor(colorList.get(position)));
mPaint.setColor(ContextCompat.getColor(mContext, R.color.color_b69b4f));
//画圆饼图每块边上的折线
canvas.drawLines(floats, mPaint);
mPaint.setStyle(Paint.Style.STROKE);
//绘制显示的文字,需要根据类型显示不同的文字
if (mRateList.size() > 0) {
//Y轴：+ textRect.height() / 2 ,相对沿线居中显示
canvas.drawText(getFormatPercentRate(mRateList.get(position) * 100) + "%", floats[6], floats[7] + textRect.height() / 2, mPaint);
}
}
private void dealPoint(RectF rectF, float startAngle, float endAngle, List pointList) {
Path path = new Path();
//通过Path类画一个90度（180—270）的内切圆弧路径
path.addArc(rectF, startAngle, endAngle);
PathMeasure measure = new PathMeasure(path, false);
// Log.e("路径的测量长度:", "" + measure.getLength());
float[] coords = new float[]{0f, 0f};
//利用PathMeasure分别测量出各个点的坐标值coords
int divisor = 1;
measure.getPosTan(measure.getLength() / divisor, coords, null);
// Log.e("coords:", "x轴:" + coords[0] + " -- y轴:" + coords[1]);
float x = coords[0];
float y = coords[1];
Point point = new Point(Math.round(x), Math.round(y));
pointList.add(point);
}
public void updateDate(List rateList, List colorList, boolean isShowRateText) {
this.isShowRateText = isShowRateText;
this.mRateList = rateList;
this.mColorList = colorList;
init();
invalidate();
}
/**
* 获取格式化的保留两位数的数
*/
public String getFormatPercentRate(float dataValue) {
DecimalFormat decimalFormat = new DecimalFormat(".00");//构造方法的字符格式这里如果小数不足2位,会以0补足.
return decimalFormat.format(dataValue);
}
}