错误！在安装的Android SDK中找不到API版本：2.1

我正在使用Rhomobile框架在Ruby中开始Android开发。我试图运行Android的错误！在安装的Android SDK中找不到API版本：2.1

rake run:android

rake命令，但我发现了以下错误

ERROR!!! API version is not found in installed Android SDK: 2.1

如何解决它的任何暗示？

也是我rhobuild.yml文件看起来像

env: 
app: /Users/bhushan/rhodes_learn/employee_app 
paths: 
android-ndk: /Users/bhushan/android-ndk-r7 
java: /Library/Java/Home/bin 
android: /Users/bhushan/android-sdk-macosx 
4.6: 
    jde: 
    sim: 9000 
    mds: 
cabwiz: 
4.2: 
    jde: 
    sim: 8100 
    mds: 
excludedirs: 
bb: 
- public/js/iui 
- public/js/jquery* 
- public/jqtouch* 
- public/js/prototype* 
- public/css/iphone* 
- public/iwebkit 
- public/themes 
- "**/jquery*.js" 
- "**/*.db" 
- public/images/android 
- public/images/iphone 
all: 
- "**/.*.swo" 
- "**/.*.swn" 
- "**/.DS_Store" 
android: 
build: 
symbianpath: platform/symbian 
bb: 
bbsignpwd: somepasswordhere 
bbpath: platform/bb 
wmpath: platform/wm 
androidpath: platform/android 
wppath: platform/wp7 
iphonepath: platform/iphone

来源

2012-01-03 Bhushan Lodha