CenterVerticalTextSpan

/**
 * 使TextView中不同大小字体垂直居中
 * Created by Robin on 2018/11/8.
 * Email: robinxdroid@gmail.com
 * Blog: http://robinx.net/
 */
public class CenterVerticalTextSpan extends ReplacementSpan {
    private int fontSizePx;    //字体大小px

    public CenterVerticalTextSpan(int fontSizePx) {
        this.fontSizePx = fontSizePx;
    }

    @Override
    public int getSize(Paint paint, CharSequence text, int start, int end, Paint.FontMetricsInt fm) {
        text = text.subSequence(start, end);
        Paint p = getCustomTextPaint(paint);
        return (int) p.measureText(text.toString());
    }

    @Override
    public void draw(Canvas canvas, CharSequence text, int start, int end, float x, int top, int y, int bottom, Paint paint) {
        text = text.subSequence(start, end);
        Paint p = getCustomTextPaint(paint);
        Paint.FontMetricsInt fm = p.getFontMetricsInt();
        canvas.drawText(text.toString(), x, y - ((y + fm.descent + y + fm.ascent) / 2 - (bottom + top) / 2), p);    //此处重新计算y坐标，使字体居中
    }

    private TextPaint getCustomTextPaint(Paint srcPaint) {
        TextPaint paint = new TextPaint(srcPaint);
        paint.setTextSize(fontSizePx);   //设定字体大小, sp转换为px
        return paint;
    }
}

转载请指明出处RobinBlog：http://robinx.net/2018/11/12/CenterVerticalTextSpan/