Android ApiDemos示例解析(73):Graphics->Points

本例对应的例子为DrawPoints.java,介绍如何使用Canvas来绘制点。

Canvas 提供3个重载函数来绘制点（单个点或是一组点）

public void drawPoint(float x, float y, Paint paint)public void drawPoints(float[] pts, Paint paint)public void drawPoints(float[] pts, int offset, int count, Paint paint)

绘制点的中心由点的坐标给定，点的宽度由Paint的Stroke宽度指定（并受当前Canvas的Matrix影响）。stroke width为0比较特殊，点的宽度总为1个像素（打开Antialiasing支持时为4个像素）。

本例绘制一组点和由点连接的直线:

Paint paint = mPaint; canvas.translate(10, 10); canvas.drawColor(Color.WHITE); paint.setColor(Color.RED);paint.setStrokeWidth(0);canvas.drawLines(mPts, paint); paint.setColor(Color.BLUE);paint.setStrokeWidth(3);canvas.drawPoints(mPts, paint);