在Android View中，在外面画一个虚线圆圈

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.DashPathEffect;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.AttributeSet;
import android.view.View;

public class DottedCircleView extends View {
    private Paint paint;
    private Path path;

    public DottedCircleView(Context context) {
        super(context);
        init();
    }

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

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

    private void init() {
        paint = new Paint();
        paint.setStyle(Paint.Style.STROKE);
        paint.setColor(Color.BLACK);
        paint.setPathEffect(new DashPathEffect(new float[]{10, 10}, 0));
        paint.setStrokeWidth(2);

        path = new Path();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        int centerX = getWidth() / 2;
        int centerY = getHeight() / 2;
        int radius = Math.min(centerX, centerY) - 10;

        path.reset();
        path.addCircle(centerX, centerY, radius, Path.Direction.CW);

        canvas.drawPath(path, paint);
    }
}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <com.example.myapplication.DottedCircleView
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:layout_gravity="center" />

</LinearLayout>