在TextView中的文本的特定部分后面绘制矩形

public class CustomBackgroundSpan extends ReplacementSpan {
    @Override
    public int getSize(Paint paint, CharSequence text, int start, int end, Paint.FontMetricsInt fm) {
        // 返回绘制内容的宽度
        return (int) paint.measureText(text, start, end);
    }

    @Override
    public void draw(Canvas canvas, CharSequence text, int start, int end, float x, int top, int y, int bottom, Paint paint) {
        // 绘制矩形
        Rect rect = new Rect((int) x, top, (int) (x + paint.measureText(text, start, end)), bottom);
        paint.setColor(Color.RED);
        canvas.drawRect(rect, paint);
    }
}

TextView textView = findViewById(R.id.textView);
String text = "这是一段示例文本";
SpannableString spannableString = new SpannableString(text);

// 将自定义的BackgroundSpan应用到特定位置
CustomBackgroundSpan backgroundSpan = new CustomBackgroundSpan();
spannableString.setSpan(backgroundSpan, 4, 6, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

textView.setText(spannableString);