TextView:Layout、TextPaint、FontMe

附件已上传github：TextLocationHelper.java

1.获取文字高度：

Paint.FontMetrics fm = textPaint.getFontMetrics();
textHeight = (int) (fm.bottom+fm.top);

2.测量文字宽度：
textPaint.measureText(mText);

代码示例：

TextPaint textPaint = new TextPaint(Paint.ANTI_ALIAS_FLAG); 
textPaint.setTextSize(12);
textPaint.setColor(Color.BLUE);

//PorterDuffColorFilter  lastPicWithMpore =
//new PorterDuffColorFilter(Color.parseColor("#7f000000"), PorterDuff.Mode.SRC_ATOP);//灰色遮罩

Paint.FontMetrics fm = textPaint.getFontMetrics();
//获取文字高度
textHeight = (int) (fm.bottom+fm.top);

//测量文字宽度
float textWidth = textPaint.measureText(mText); 
int x_offset = (int) (getWidth()-textWidth)/2;
if(x_offset<0){
    x_offset = 0;
}
int y_offset = (getHeight()-textHeight)/2;
canvas.drawText(mText,x_offset,y_offset,textPaint);

3. 根据坐标获取文字的offset：

//x,y
int line = layout.getLineForVertical(y);                  //根据纵坐标获取所对应的行
int ofset = layout.getOffsetForHorizontal(line, x);  //根据行和横坐标获取文字的offset
float lineRight = layout.getLineRight(line);            //获取该行最有边的距离（也就是横坐标）

4.根据文字offset获取该文字处的坐标

//根据字符所在位置的偏移量计算该字符左下角的坐标，坐标是相对于该TextView的
private static int[] getFixXYByTextviewOffset(TextView tv, int offset) {
    Layout layout = tv.getLayout();
    if (layout != null) {
        int line = layout.getLineForOffset(offset);    //根据文字offset获取所在的行
        int base = layout.getLineBottom(line);    
        //修正纵坐标用，暂未使用
        int lineYxiuZheng = layout.getLineDescent(line);

        int relativeX = (int) layout.getPrimaryHorizontal(offset) - tv.getScrollX(); // x
        int relativeY  = base - tv.getScrollY(); // y
        return new int[]{relativeX,relativeY};
    }
    return null;
}

5. 判断offset是否在行的结尾

/**返回该offset是否在行的结尾*/
private static boolean isEndOfLineOffset(TextView tv,int offset) {
    if (offset > 0) {
        return tv.getLayout().getLineForOffset(offset) ==
                tv.getLayout().getLineForOffset(offset - 1) + 1;
    }
    return false;
}