I believe I've followed the instructions in the Android SDK, and I'm now trying to build the sample LunarLander (random one picked)
$ cd samples/android-11/LunarLander
$ ant debug
Buildfile: build.xml does not exist!
Build failed
I believe all PATHs are setup correctly. I've done this before in an older Android SDK release and I know I didn't encounter this error, so I'm pretty confused as to what's wrong.
Oh, one more piece of info -- I have only installed the 3.0 platform package, so I'm not sure if that is an error or not.
You need to execute this command:
android update project --target <your build target> --path <path to LunarLander example>
which will create the needed build.xml within the example directory, then the ant debug command should work.
Take a look here.
*You can use android list targets to choose what build target to use for your project.
You'll need to create the Ant build file, using the process described here.
Running the command-line update project (should) create the Ant dependencies files for you.
android updated project was remove in SDK tools 26.0.1
Don't use Ant. It is not properly supported anymore. For now, just use Android Studio GUI and create Gradle projects manually.
android update project was finally removed in SDK tools 26.0.1 after a long deprecation period, and fails for example wth:
The "android" command is deprecated.
For manual SDK, AVD, and project management, please use Android Studio.
For command-line tools, use tools/bin/sdkmanager and tools/bin/avdmanager
*************************************************************************
Invalid or unsupported command "update project -p ./bloom -t android-23"
So now I don't know a good way to create a project from the CLI without Android Studio. The best workaround I have so far is to create a template project with Android studio, and he copy it around with a helper script as described at: How to create android project with gradle from command line?
Also I haven't managed to easily import an existing Ant project to Gradle: Doing an Ant Build on Android Studio so I just copy the sources around for now.
Before 26.0.1
When starting a new project you can use:
android create project \
--target 1 \
--name MyName \
--path . \
--activity MyActivity \
--package com.yourdomain.yourproject
which creates the build.xml automatically.
Those demo projects contain only gradlew files: I wish Google could use only one of Ant or Gradle for everything.
Please install at ubuntu openjdk-7-jdk
sudo apt-get install openjdk-7-jdk
on Windows, try find find openjdk.
来源：https://stackoverflow.com/questions/5572304/how-to-build-the-android-sample-projects-using-ant-build-xml-does-not-exist