如何在Android中使用Canvas paint在弧顶上绘制直线路径

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

public class ArcLineView extends View {
    private Paint paint;

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

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

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

    private void init() {
        paint = new Paint();
        paint.setColor(Color.BLACK);
        paint.setStrokeWidth(5);
        paint.setStyle(Paint.Style.STROKE);
    }

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

        int centerX = getWidth() / 2;
        int centerY = getHeight() / 2;
        int radius = Math.min(centerX, centerY) - 50;

        // 绘制弧形路径
        canvas.drawArc(centerX - radius, centerY - radius, centerX + radius, centerY + radius, 180, 180, false, paint);

        // 绘制直线路径
        canvas.drawLine(centerX - radius, centerY, centerX + radius, centerY, paint);
    }
}

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ArcLineView arcLineView = new ArcLineView(this);
        setContentView(arcLineView);
    }
}