If you want programming for Android on your mobile device (for example in the travels), you can use DroidDevelop.
DroidDevelop allows to create native Android application on your mobile device. You don't need to install Android SDK, Eclipce and an other desktop program for Windows or Linux to start programing for Android.
To works correctly, you need to install JavaIDEDroid for project compilation and OI FileManager for files choosing. After open or create new project (bsh script really) you can press "Compile..." and if success install and run your new androind application by "Run..." button without exit from DroidDevelop.
The program uses its own code editor with syntax highlighting, which practically does not slow down your working even on a fairly large files.
For convenience works on smartphones, there is an opportunity to rotate the screen, in addition, you can temporarily hide the button (from the menu "Project Options ...").
In the case of compilation errors, you can easily navigate to the file in which it occurred by selecting the desired item from the list. All errors are stored until the next re compilation, so you can fix several bugs without running every time a long process of compilation.
The project supports a fairly flexible plug-ins system. There are several groups of plug-ins that can be divided according to their purpose. The first group - plugins for refactoring. They can be used, for example, to comment the block of code, reformat code, in general, to write the functionality that is convenient for you.
The second type of plug-ins - a plug for new projects. It may be some educational projects for beginners (why not share their experience and help people who are just beginning to faster learn how to program), and a template for some of the same type of projects (for example, you release a series of books in its shell, then it would be convenient to automatically create an empty project book and then fill it with content.)
Well, the third type of plug-ins - the so-called universal plug-ins. Now the group is developing most rapidly. With their help, you can now create their own panel with programmable buttons directly into the DroidDevelop environment, the software is available to highlight text, display dialogs and more. If you decide to write a plugin and DroidDevelop plug-ins engine haven't enough functionality for your task (for example, I plan to finish the command to open the file in an editor) - write to email@example.com, together we will try to solve the problem.
There are three Open Source example of a plug-in which provides AsSoft: "DDRefactoringPluginExample", "DDNewProjectPluginExample", "DDPluginsCreation", you can see them at:
http://www.google.com/url?q=https://code.google.com/p/dd-refactoring-plugin-demo/source/browse/#svn%2Ftrunk&usg=AFQjCNEfFSsXZmUC8maPLCdmTjFPxu9ldg or download on the store (except for "DDPluginsCreation", but it can be compiled directly from DroidDevelop with the "DDNewProjectPluginExample" plug-in. See the video http://www.google.com/url?q=http://www.youtube.com/watch?v=U6ASfc5lOaY&feature=plcp&context=C3dbe209UDOEgsToPDskIstNOIceux7B_mp_TBBM6W)&usg=AFQjCNEChi-7Y4wK6jTUZzmKt1DjdS7qZw
Also, several floor demo plugins available from the "DDPluginsPack". It can be found at the store.