FontMetrics對(duì)象 它以四個(gè)基本坐標(biāo)為基準(zhǔn)，分別為：
?FontMetrics.top
?FontMetrics.ascent
?FontMetrics.descent
?FontMetrics.bottom
//獲取文字的寬高
Rect rect = new Rect();
wordsPaint.getTextBounds(string, 0, 1, rect);
Paint.FontMetrics fontMetrics = wordsPaint.getFontMetrics();
int wordWidth = rect.width();
//繪制字母
float wordX = itemWidth / 2 - wordWidth / 2;
// float wordY = i * itemHeight+1/2 * itemHeight + 1/2 * (fontMetrics.descent- fontMetrics.ascent) - fontMetrics.bottom;
float wordY = i * itemHeight + itemHeight / 2 +
((fontMetrics.bottom - fontMetrics.top) / 2 - fontMetrics.bottom);
