android测量文字的宽高

获取文字高度：

int textHeight = (int) (mPaint.descent()-mPaint.ascent());

1.基准线是baseline
2.ascent：字体在baseline上方被推荐的距离（一些字体制作商需要参考这个）
3.descent：字体在是baseline下方被推荐的距离（一些字体制作商需要参考这个）
4.top：ascent的最大值
5.bottom：descent的最大值

//四个值的源码：

public static class FontMetrics {
/** * The maximum distance above the baseline for the tallest glyph in * the font at a given text size. */
public float   top;
/** * The recommended distance above the baseline for singled spaced text. */
public float   ascent;
/** * The recommended distance below the baseline for singled spaced text. */
public float   descent;
/** * The maximum distance below the baseline for the lowest glyph in * the font at a given text size. */
public float   bottom;  
}

获取文字宽度：

Paint提供了下面4个重载方法，返回文本的宽度，类型是float

public float measureText(String text)
public float measureText(char[] text, int index, int count)
public float measureText(String text, int start, int end)
public float measureText(CharSequence text, int start, int end)

或者使用Paint.getTextBounds方法直接获取宽高：

 public void getTextBounds(String text, int start, int end, Rect bounds) {
        throw new RuntimeException("Stub!");
    }

String test = "QinShiMingYue";
Rect rect = new Rect();
mPaint.getTextBounds(text, 0, test.length(), rect);
int width = rect.width();//文字宽
int height = rect.height();//文字高