转自：http://www.cnblogs.com/plokmju/p/android_Canvas.html
http://blog.csdn.net/hzc543806053/article/details/7672965
http://blog.csdn.net/andyhuabing/article/details/12653183
android: 使用Canvas 绘图,布布扣,bubuko.com
原文：http://www.cnblogs.com/lomomiao/p/3629605.html