初始化
public class SpiderView extends View {
/*
* radar 美 [ˈredɑr] n.雷达
*/
private Paint radarPaint;//网格画笔
private Paint valuePaint;//结果点值画笔
private float radius;//网格最大半径
private int centerX;//中心X
private int centerY;//中心Y
public SpiderView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
private void init() {
//网格画笔，描边
radarPaint = new Paint();
radarPaint.setStyle(Paint.Style.STROKE);
radarPaint.setColor(Color.RED);
//结果点值画笔，填充
valuePaint = new Paint();
valuePaint.setColor(Color.BLUE);
valuePaint.setStyle(Paint.Style.FILL);
}
}
获得布局中心
在onSizeChanged()中，
根据View的长宽，
获取整个布局的中心坐标，
以及计算网状多边形的半径，
后续整个蜘蛛网都是从这个中心坐标开始绘制的：
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
//计算多边形半径
radius = Math.min(w, h)/ 2 * 0.9f;
//计算中心坐标
centerX = w/2;
centerY = h/2;
postInvalidate();
super.onSizeChanged(w, h, oldw, oldh);
}
- 当控件大小发生变化时，
都会通过onSizeChanged()通知当前控件的大小；
所以只要重写onSizeChanged(),
即可在其中计算得知控件的最新大小；
开始绘制
绘制的架构
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
//绘制蜘蛛网状图
drawPolygon(canvas);
//绘制网格中线
drawLines(canvas);
//绘制数据
drawRegion(canvas);
}
绘制蜘蛛网络
效果如下：
- 绘制思路：
利用Path的moveTo()和lineTo()，一圈圈画出来；
需要计算每个转折点的位置；
（下面angle即为以上所述夹角a）
float x = (float) (centerX + curR * Math.cos(angle * j));
float y = (float) (centerY + curR * Math.sin(angle * j));
-
因为我们共画了6个角，
count = 6;
则每个角的度数为360 / 6 = 60度，
不过这里注意不要写angle = 60;……
不然……悲剧如下：
-
众所周知，
三角函数以π为基数进行运算，
下面这行代码才是正解！
angle = (float) (Math.PI * 2 / count);
实际使用时候具体调整；
根据以上原理，绘制蜘蛛网圈代码如下：
private void drawPolygon(Canvas canvas) {
Path path = new Path();
float r = radius / count; //r 是网圈之间的间隔
//逐个绘制网的单圈，从第1圈（一个r距离）开始画，直到count个，
// 中心点（0个r距离）不用绘制
for(int i = 1; i<= count; i++){
float curR = r * i;//当前 半径 / 距离中心的偏移量
path.reset();//每一圈的开始，都要重置
//从 0度 开始，绘制到 （count-1）* angle 度
// < count ，即 （count-1）
for(int j = 0; j < count; j++) {
if(j == 0){
//绘制 0度 的点 ，都是 0度 ，同一直线， 同在centerY
path.moveTo(centerX + curR , centerY);
} else {
//根据半径，计算出蜘蛛网圈上的每一个点的坐标
float x = (float) (centerX + curR * Math.cos(angle * j));
float y = (float) (centerY + curR * Math.sin(angle * j));
path.lineTo(x, y);
}
}
//画完一圈点之后
path.close();
canvas.drawPath(path, radarPaint);//落实绘制路径
}
}
绘制网格中线
- 绘制原理与绘制蜘蛛网圈的原理差不多，
利用三角函数
以中心点为线段开始：path.moveTo(centerX, centerY); - 再找到各个末端点的坐标，
用for循环向数个末端点逐个连线即可：lineTo(x, y); - 注意每次画完一条线段，
需要重置一下路径：path.reset();
private void drawLines(Canvas canvas) {
Path path = new Path();
for(int i = 0; i < count; i++) {
//注意每次画完一条线段，需要重置一下路径
path.reset();
path.moveTo(centerX, centerY);//以中心点为线段开始
//找到各个末端点的坐标
float x = (float) (centerX + radius * Math.cos(angle * i));
float y = (float) (centerY + radius * Math.sin(angle * i));
path.lineTo(x, y);
canvas.drawPath(path, radarPaint);
}
}
绘制数据图
思路：
- 确定每个数据点的位置；
- 网状图的每一层网格都应该对应一个数值；
- 这里简单将最大值设置为6，
即每一层数值是按1,2,3,4,5,6分布的：
private void init() {
//网格画笔，描边
radarPaint = new Paint();
radarPaint.setStyle(Paint.Style.STROKE);
radarPaint.setColor(Color.RED);
//结果点值画笔，填充
valuePaint = new Paint();
valuePaint.setColor(Color.BLUE);
valuePaint.setStyle(Paint.Style.FILL);
//初始化数据
data = new double[]{1, 2, 3, 4, 5, 6};
maxValue = 6;
}
具体实现代码：
private void drawRegion(Canvas canvas) {
Path path = new Path();
valuePaint.setAlpha(127);
for (int i = 0; i < count; i++) {
float percent = (float) data[i] / maxValue;
tempR = radius * percent;//按比例归一化取值
float x = (float) (centerX + tempR * Math.cos(angle * i));
float y = (float) (centerY + tempR * Math.sin(angle * i));
if (i == 0) {
path.moveTo(x, centerY);
}else{
path.lineTo(x, y);
}
//绘制小圆点
canvas.drawCircle(x, y, 10, valuePaint);
}
//绘制填充区域
valuePaint.setStyle(Paint.Style.FILL_AND_STROKE);
canvas.drawPath(path, valuePaint);
}
调节网图大小，增加末端标题文本
private void drawTexts(Canvas canvas) {
for (int i = 0; i < count; i++) {
tempR = radius * 1.1f;//按比例归一化取值
float x = (float) (centerX + tempR * Math.cos(angle * i));
float y = (float) (centerY + tempR * Math.sin(angle * i));
if (i == 0) {
canvas.drawText(titles[i], x - 0.1f*tempR , centerY, textPaint);
}else{
canvas.drawText(titles[i], x , y, textPaint);
}
}
}
- 定义与初始化变量这部分就不赘述了，文末附上全文代码，敬请小伙伴们指教观看
附上全文代码：
public class SpiderView extends View {
/*
* radar 美 [ˈredɑr] n.雷达
*/
private Paint radarPaint;//网格画笔
private Paint valuePaint;//结果点值画笔
private Paint textPaint;//末端标题画笔
private float radius;//网格最大半径
private float tempR;//用于计算和设置UI的临时变量
private int centerX;//中心X
private int centerY;//中心Y
private int count;
private float angle;
private String[] titles;//某端点标题文本
private double[] data;//各角数据
private float maxValue;//最大值
public SpiderView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
private void init() {
//网格画笔，描边
radarPaint = new Paint();
radarPaint.setStyle(Paint.Style.STROKE);
radarPaint.setColor(Color.RED);
radarPaint.setAntiAlias(true);
//结果点值画笔，填充
valuePaint = new Paint();
valuePaint.setColor(Color.BLUE);
valuePaint.setStyle(Paint.Style.FILL);
valuePaint.setAntiAlias(true);
textPaint = new Paint();
textPaint.setColor(Color.BLACK);
textPaint.setTextSize(30);
textPaint.setStyle(Paint.Style.FILL);
textPaint.setAntiAlias(true);
//初始化数据
data = new double[]{0.5, 1.5, 0.3, 6, 15, 6};
maxValue = 6;
titles = new String[]{"王者农药", "吃鸡", "剁手", "读书", "书法", "民乐"};
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
//计算多边形半径
radius = (float) Math.min(w, h) / 2 * 0.7f;
//计算中心坐标
centerX = w / 2;
centerY = h / 2;
//边数与角度
count = 6;
// angle = 60; //The bad operation!!!!!!——别干傻事
angle = (float) (Math.PI * 2 / count);
postInvalidate();
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
//绘制蜘蛛网状图
drawPolygon(canvas);
//绘制网格中线
drawLines(canvas);
//绘制数据
drawRegion(canvas);
//绘制末端文本
drawTexts(canvas);
}
private void drawTexts(Canvas canvas) {
for (int i = 0; i < count; i++) {
tempR = radius * 1.1f;//按比例归一化取值
float x = (float) (centerX + tempR * Math.cos(angle * i));
float y = (float) (centerY + tempR * Math.sin(angle * i));
if (i == 0) {
canvas.drawText(titles[i], x - 0.1f*tempR , centerY, textPaint);
}else{
canvas.drawText(titles[i], x , y, textPaint);
}
}
}
private void drawRegion(Canvas canvas) {
Path path = new Path();
valuePaint.setAlpha(127);
for (int i = 0; i < count; i++) {
float percent = (float) data[i] / maxValue;
tempR = radius * percent;//按比例归一化取值
float x = (float) (centerX + tempR * Math.cos(angle * i));
float y = (float) (centerY + tempR * Math.sin(angle * i));
if (i == 0) {
path.moveTo(x, centerY);
}else{
path.lineTo(x, y);
}
//绘制小圆点
canvas.drawCircle(x, y, 10, valuePaint);
}
//绘制填充区域
valuePaint.setStyle(Paint.Style.FILL_AND_STROKE);
canvas.drawPath(path, valuePaint);
}
private void drawLines(Canvas canvas) {
Path path = new Path();
for (int i = 0; i < count; i++) {
//注意每次画完一条线段，需要重置一下路径
path.reset();
path.moveTo(centerX, centerY);//以中心点为线段开始
//找到各个末端点的坐标
float x = (float) (centerX + radius * Math.cos(angle * i));
float y = (float) (centerY + radius * Math.sin(angle * i));
path.lineTo(x, y);
canvas.drawPath(path, radarPaint);
}
}
//！！！！！！
//排查之后发现问题不在这里，重点是angle的取值！！！！！！！！！！
//！！！！！！
private void drawPolygon(Canvas canvas) {
Path path = new Path();
float r = radius / count; //r 是网圈之间的间隔
//逐个绘制网的单圈，从第1圈（一个r距离）开始画，直到count个，
// 中心点（0个r距离）不用绘制
for (int i = 1; i <= count; i++) {
float curR = r * i;//当前 半径 / 距离中心的偏移量
path.reset();//每一圈的开始，都要重置
//从 0度 开始，绘制到 （count-1）* angle 度
// < count ，即 （count-1）
for (int j = 0; j < count; j++) {
if (j == 0) {
//绘制 0度 的点 ，都是 0度 ，同一直线， 同在centerY
path.moveTo(centerX + curR, centerY);
} else {
//根据半径，计算出蜘蛛网圈上的每一个点的坐标
float x = (float) (centerX + curR * Math.cos(angle * j));
float y = (float) (centerY + curR * Math.sin(angle * j));
path.lineTo(x, y);
}
}
//画完一圈点之后
path.close();
canvas.drawPath(path, radarPaint);//落实绘制路径
}
}
//设置标题
public void setTitles(String[] titles) {
this.titles = titles;
}
//设置数值
public void setData(double[] data) {
this.data = data;
}
//设置最大数值
public void setMaxValue(float maxValue) {
this.maxValue = maxValue;
}
//设置蜘蛛网颜色
public void setMainPaintColor(int color) {
radarPaint.setColor(color);
}
//设置覆盖局域颜色
public void setValuePaintColor(int color) {
valuePaint.setColor(color);
}
//设置边数
public void setCount(int count) {
this.count = count;
}
public void setRadarPaint(Paint radarPaint) {
this.radarPaint = radarPaint;
}
public void setValuePaint(Paint valuePaint) {
this.valuePaint = valuePaint;
}
public void setTextPaint(Paint textPaint) {
this.textPaint = textPaint;
}
public void setRadius(float radius) {
this.radius = radius;
}
public void setCenterX(int centerX) {
this.centerX = centerX;
}
public void setCenterY(int centerY) {
this.centerY = centerY;
}
public void setAngle(float angle) {
this.angle = angle;
}
}
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