All required tools to develop Android applications are freely available and can be download from the Web.
Android Studio provides the fastest tools for building apps on every type of Android device. Android Studio is official IDE of android. Android application can be developed on either of the following operating systems...
To download and install Android Studio go to https://developer.android.com/studio/index.html and download appropriate installer for your system.
Linux, suppose JDK is installed in /usr/local/jdk1.6.0_15. Use C shell and put following code into your .cshrc file.
setenv PATH /usr/local/jdk1.7.0_75/bin:$PATH
setenv JAVA_HOME /usr/local/jdk1.7.0_75