Android编程之绘制文本（FontMetrics）实现方法

本文实例讲述了android编程之绘制文本（fontmetrics）实现方法。分享给大家供大家参考，具体如下：

canvas 作为绘制文本时，使用fontmetrics对象，计算位置的坐标。

它的思路和java.awt.fontmetrics的基本相同。

fontmetrics对象

它以四个基本坐标为基准，分别为：

fontmetrics.top
fontmetrics.ascent
fontmetrics.descent
fontmetrics.bottom

该图片将如下

代码如下：

paint textpaint = new paint( paint.anti_alias_flag); 
textpaint.settextsize( 35); 
textpaint.setcolor( color.white); 
// fontmetrics对象 
fontmetrics fontmetrics = textpaint.getfontmetrics(); 
string text = "abcdefghijklmnopqrstu"; 
// 计算每一个坐标 
float basex = 0; 
float basey = 100; 
float topy = basey + fontmetrics.top; 
float ascenty = basey + fontmetrics.ascent; 
float descenty = basey + fontmetrics.descent; 
float bottomy = basey + fontmetrics.bottom; 
// 绘制文本 
canvas.drawtext( text, basex, basey, textpaint); 
// baseline描画 
paint baselinepaint = new paint( paint.anti_alias_flag);> 
baselinepaint.setcolor( color.red); 
canvas.drawline(0, basey, getwidth(), basey, baselinepaint); 
// base描画 
canvas.drawcircle( basex, basey, 5, baselinepaint); 
// topline描画 
paint toplinepaint = new paint( paint.anti_alias_flag); 
toplinepaint.setcolor( color.ltgray); 
canvas.drawline(0, topy, getwidth(), topy, toplinepaint); 
// ascentline描画 
paint ascentlinepaint = new paint( paint.anti_alias_flag); 
ascentlinepaint.setcolor( color.green); 
canvas.drawline(0, ascenty, getwidth(), ascenty, ascentlinepaint); 
// descentline描画 
paint descentlinepaint = new paint( paint.anti_alias_flag); 
descentlinepaint.setcolor( color.yellow); 
canvas.drawline(0, descenty, getwidth(), descenty, descentlinepaint); 
// buttomline描画 
paint bottomlinepaint = new paint( paint.anti_alias_flag); 
bottomlinepaint.setcolor( color.magenta); 
canvas.drawline(0, bottomy, getwidth(), bottomy, bottomlinepaint); 

希望本文所述对大家android程序设计有所帮助。