Android不同分辨率launcher icon的适配

网上讲android适配不同分辨率的文章很多，但是很少有说明不同分辨率的屏幕应该对应多大分辨率的app icon，这里做一个说明：

To create alternative bitmap drawables for different densities, you should follow the 3:4:6:8:12:16 scaling ratio between the six generalized densities. For example, if you have a bitmap drawable that's 48x48 pixels for medium-density screens, all the different sizes should be:

36x36 (0.75x) for low-density
48x48 (1.0x baseline) for medium-density
72x72 (1.5x) for high-density
96x96 (2.0x) for extra-high-density
180x180 (3.0x) for extra-extra-high-density // 根据3:4:6:8:12:16的比例，这里应该是144，可能是官方文档的疏忽？
192x192 (4.0x) for extra-extra-extra-high-density (launcher icon only; see note above)

出处：http://developer.android.com/guide/practices/screens_support.html