要實(shí)現(xiàn)這樣的效果：

屏幕快照 2018-04-29 下午2.49.01.png

用UnderlineSpan、Html實(shí)現(xiàn)的效果不是很好，決定繼承LineBackgroundSpan逐行畫(huà)線，效果不錯(cuò)。記錄下：

/**
 * 自定義的UnderlineSpan，用于給TextView底部畫(huà)直線
 *
 * 建議在layout里給textView設(shè)置includeFontPadding=false，并且設(shè)置lineSpacingMultiplier/lineSpacingExtra
 * 和paddingBottom以留出底部空間畫(huà)線
 */
public class CustomUnderlineSpan implements LineBackgroundSpan {
    private Paint paint;
    private TextView textView;
    private float offsetY;

    /**
     *
     * @param textView 被畫(huà)線的textview
     * @param color 底部畫(huà)線的顏色
     * @param lineHeight 畫(huà)線的高度（像素值）
     * @param offsetY 畫(huà)線相對(duì)于textView行高從上往下的偏移距離（像素值）
     */
    public CustomUnderlineSpan(TextView textView, int color, float lineHeight, float offsetY) {
        paint = new Paint();
        paint.setColor(color);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeWidth(lineHeight);
        this.textView = textView;
        this.offsetY = offsetY;
    }

    @Override
    public void drawBackground(Canvas canvas, Paint p, int left, int right, int top, int baseline,
                               int bottom, CharSequence text, int start, int end, int lnum) {
        int lineNum = textView.getLineCount();
        Layout layout = textView.getLayout();
        float y;
        for (int i = 0; i < lineNum; i++) {
            y = layout.getLineTop(i) + offsetY;
            canvas.drawLine(layout.getLineLeft(i), y, layout.getLineRight(i), y, paint);
        }
    }
}

調(diào)起來(lái)：

SpannableString ss = new SpannableString(text);
ss.setSpan(new CustomUnderlineSpan(binding.title,
                            Color.parseColor("#C7FFE921"),
                            UIUtil.INSTANCE.dipToPixels(8),
                            UIUtil.INSTANCE.dipToPixels(22)),
                    0, intSpannableStringBuilderLength,
                    Spanned.SPAN_INCLUSIVE_INCLUSIVE);
title.setText(ss);