实例 创建一个圆形: var c=document.getElementById("myCanvas"); var ctx=c.getContext("2d"); ctx.beginPath(); ctx.arc(100,75,50,0,2*Math.PI); ctx.stroke(); 浏览器支持 Internet Explorer 9.Firefox.Opera.Chrome 以及 Safari 支持 arc() 方法. 注释:Internet Explorer
protected void onAttachedToWindow() This is called when the view is attached to a window. At this point it has a Surface and will start drawing. Note that this function is guaranteed to be called before onDraw(android.graphics.Canvas), however it
一.模板方法模式定义 模板方法模式定义: defines the skeleton of an algorithm in a method, deferring some steps to subclasses. Template Method lets subclasses redefine certain steps of an algorithm without changing the algorithm's structure. 定义一个方法操作算法的框架(骨架结构),而将一些步骤延迟