目录
1 思路：
2 实现：
3 效果：
查看RadarChart控件源码，找到绘制网线的相关源码，获取到各个顶点的坐标后，便可以在各个顶点绘制圆。
Step 1：既然圆点是在网线各个顶点，那便跟绘制网线相关联，我们可以从绘制网线的公开方法入手去查找，最先想到就是setDrawWeb方法，直接影响网线的绘制，这个方法也很简单只设置了mDrawWeb的值。
Step 2：接下来我们要查找变量mDrawWeb在绘制中的实际已应用，绘制便跟onDraw方法有关。可以看出绘制网线时，调用了mRenderer变量的drawExtras(canvas)。
Step 3：查找mRenderer变量的具体对象。
Step 4：查找RadarChartRenderer对象中drawExtras(canvas)方法到底做了什么事情。
Step 5：drawExtras(canvas)方法中如下这段代码是绘制每段网线的，从中可以获取到各个顶点的坐标。
Step 6：通过该坐标在里面进行圆点的绘制，由于我们无法直接编辑源码，我们还需要重写RadarChart和RadarChartRenderer这两个类。
Step 1：新建我们自己的RadarChartRenderer类继承RadarChartRenderer，重写drawWeb(Canvas c)方法，里面内容直接拷贝原方法代码后在指定加上如下这段代码。
for (int j = 0; j < labelCount; j++) { for (int i = 0; i < mChart.getData().getEntryCount(); i++) { float r = (mChart.getYAxis().mEntries[j] - mChart.getYChartMin()) * factor; Utils.getPosition(center, r, sliceangle * i + rotationangle, p1out); Utils.getPosition(center, r, sliceangle * (i + 1) + rotationangle, p2out); c.drawLine(p1out.x, p1out.y, p2out.x, p2out.y, mWebPaint); // start（加上下面这几行代码，用于绘制每个顶角上的圆） if (mDrawAngleCircle && j == labelCount - 1) { mAngleCirclePaint.setColor(mAngleCircleColors == null || mAngleCircleColors.length == 0 ? Color.BLACK : this.mAngleCircleColors[i % mAngleCircleColors.length]); c.drawCircle(p2out.x, p2out.y, mAngleCircleRadius, mAngleCirclePaint); } // end } }完整代码：
import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import com.github.mikephil.charting.animation.ChartAnimator; import com.github.mikephil.charting.charts.RadarChart; import com.github.mikephil.charting.utils.MPPointF; import com.github.mikephil.charting.utils.Utils; import com.github.mikephil.charting.utils.ViewPortHandler; public class RadarChartRenderer extends com.github.mikephil.charting.renderer.RadarChartRenderer { private Paint mAngleCirclePaint; private float mAngleCircleRadius = Utils.convertDpToPixel(5f); private int[] mAngleCircleColors; private boolean mDrawAngleCircle = false; public RadarChartRenderer(RadarChart chart, ChartAnimator animator, ViewPortHandler viewPortHandler) { super(chart, animator, viewPortHandler); mAngleCirclePaint = new Paint(); } @Override protected void drawWeb(Canvas c) { float sliceangle = mChart.getSliceAngle(); // calculate the factor that is needed for transforming the value to // pixels float factor = mChart.getFactor(); float rotationangle = mChart.getRotationAngle(); MPPointF center = mChart.getCenterOffsets(); // draw the web lines that come from the center mWebPaint.setStrokeWidth(mChart.getWebLineWidth()); mWebPaint.setColor(mChart.getWebColor()); mWebPaint.setAlpha(mChart.getWebAlpha()); final int xIncrements = 1 + mChart.getSkipWebLineCount(); int maxEntryCount = mChart.getData().getMaxEntryCountSet().getEntryCount(); MPPointF p = MPPointF.getInstance(0,0); for (int i = 0; i < maxEntryCount; i += xIncrements) { Utils.getPosition( center, mChart.getYRange() * factor, sliceangle * i + rotationangle, p); c.drawLine(center.x, center.y, p.x, p.y, mWebPaint); } MPPointF.recycleInstance(p); // draw the inner-web mWebPaint.setStrokeWidth(mChart.getWebLineWidthInner()); mWebPaint.setColor(mChart.getWebColorInner()); mWebPaint.setAlpha(mChart.getWebAlpha()); int labelCount = mChart.getYAxis().mEntryCount; MPPointF p1out = MPPointF.getInstance(0,0); MPPointF p2out = MPPointF.getInstance(0,0); for (int j = 0; j < labelCount; j++) { for (int i = 0; i < mChart.getData().getEntryCount(); i++) { float r = (mChart.getYAxis().mEntries[j] - mChart.getYChartMin()) * factor; Utils.getPosition(center, r, sliceangle * i + rotationangle, p1out); Utils.getPosition(center, r, sliceangle * (i + 1) + rotationangle, p2out); c.drawLine(p1out.x, p1out.y, p2out.x, p2out.y, mWebPaint); // start（加上下面这几行代码，用于绘制每个顶角上的圆） if (mDrawAngleCircle && j == labelCount - 1) { mAngleCirclePaint.setColor(mAngleCircleColors == null || mAngleCircleColors.length == 0 ? Color.BLACK : this.mAngleCircleColors[i % mAngleCircleColors.length]); c.drawCircle(p2out.x, p2out.y, mAngleCircleRadius, mAngleCirclePaint); } // end } } MPPointF.recycleInstance(p1out); MPPointF.recycleInstance(p2out); } /** * 顶角圆点颜色 * @param colors 颜色 */ public void setAngleCircleColor(int[] colors) { this.mAngleCircleColors = colors; } /** * 顶角圆点半径 * @param radius 半径 */ public void setAngleCircleRadius(float radius) { this.mAngleCircleRadius = Utils.convertDpToPixel(radius); } /** * 是否绘制顶角圆点 * @param draw */ public void setDrawAngleCircle(boolean draw) { this.mDrawAngleCircle = draw; } }Step 2：新建我们自己的RadarChart类继承RadarChart，重写init()方法。
@Override protected void init() { super.init(); this.mRenderer = new RadarChartRenderer(this, mAnimator, mViewPortHandler); }完整代码：
import android.content.Context; import android.util.AttributeSet; public class RadarChart extends com.github.mikephil.charting.charts.RadarChart { public RadarChart(Context context) { super(context); } public RadarChart(Context context, AttributeSet attrs) { super(context, attrs); } public RadarChart(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } @Override protected void init() { super.init(); this.mRenderer = new RadarChartRenderer(this, mAnimator, mViewPortHandler); } /** * 是否绘制顶角圆点 * @param draw */ public void setDrawAngleCircle(boolean draw) { ((RadarChartRenderer) this.mRenderer).setDrawAngleCircle(draw); } /** * 顶角圆点颜色 * @param colors 颜色 */ public void setAngleCircleColor(int[] colors) { ((RadarChartRenderer) this.mRenderer).setAngleCircleColor(colors); } /** * 顶角圆点半径 * @param radius 半径 */ public void setAngleCircleRadius(float radius) { ((RadarChartRenderer) this.mRenderer).setAngleCircleRadius(radius); } }Step 3：在界面中，使用我们自己RadarChart，再开启绘制顶点圆点，设置颜色。
rc.setDrawAngleCircle(true); rc.setAngleCircleColor(new int[] { Color.parseColor("#36a9ce"), Color.parseColor("#33ff66"), Color.parseColor("#ef5aa1"), Color.parseColor("#ff0000"), Color.parseColor("#6600ff") });
雷达图的使用教程：https://blog.csdn.net/Honiler/article/details/90407390
