Android：如何为同一设备英寸使用不同的布局资源？

I have an app that I developed mainly for 10 inches. However, I need to code it for 7 inches. I have two 7 inches tablets: Samsung P1000 and Samsung Tab 2 P3100. They use different Android Versions - 2.x and 4.0 respectively. Using a layout from /res/layout-large, fits well for P1000, but gets very small for P3100.I have an app that I developed mainly for 10 in