<condition property="sdk-folder"
value="E:\android\android-sdk\adt-bundle-windows-x86_64-20130219\sdk"
else="${env.ANDROID_SDK_HOME}" >
<or>
<equals arg1="${env.ANDROID_SDK_HOME}" arg2=""/>
<not>
<isset property="env.ANDROID_SDK_HOME"/>
</not>
</or>
</condition>
上述文本的逻辑就是
if(env.ANDROID_SDK_HOME==NULL || env.ANDROID_SDK_HOME == "")
{
sdk-folder = "E:\android\android-sdk\adt-bundle-windows-x86_64-20130219\sdk";
}else
{
sdk-folder = env.ANDROID_SDK_HOME
}