如何在Android画布中绘制带有文本的矩形按钮？

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

public class CustomButton extends View {
    private String buttonText;
    private Paint buttonPaint;
    private Paint textPaint;

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

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

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

    private void init() {
        buttonText = "Button";
        buttonPaint = new Paint();
        buttonPaint.setColor(Color.BLUE);

        textPaint = new Paint();
        textPaint.setColor(Color.WHITE);
        textPaint.setTextSize(40);
    }

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

        int width = getWidth();
        int height = getHeight();

        // 绘制矩形按钮
        canvas.drawRect(0, 0, width, height, buttonPaint);

        // 绘制文本
        Rect textBounds = new Rect();
        textPaint.getTextBounds(buttonText, 0, buttonText.length(), textBounds);
        int textWidth = textBounds.width();
        int textHeight = textBounds.height();
        int x = (width - textWidth) / 2;
        int y = (height + textHeight) / 2;
        canvas.drawText(buttonText, x, y, textPaint);
    }
}

<com.example.CustomButton
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />