Maybe for some people still wonder how to develop android app, with the many has listing on android market by free or paid and you want you want to start developing Android apps then this article can help you to start Android application development.

Android mobile platforms from Google Inc has using by T-Mobile, Intel, HTC, Qualcomm, Motorola along with many other companies came under the umbrella of the Open Handset Alliance – a global alliance between technology and mobile industry leaders. Android came as an operating system for mobile devices such as Smartphone and tablet computers developed by the Open Handset Alliance led by Google.
The Android platform consists of an operating system, middleware, a user-friendly interface and powerful applications. This fully integrated bundle of software significantly lower the current costs of developing mobile devices and services.
Core Design of Android: Android consists of a kernel based on the Linux kernel, with middleware, libraries and APIs written in C and application software running on an application framework which includes Java-compatible libraries based on Apache Harmony. Android uses the Dalvik virtual machine with just-in-time compilation to run compiled Java code. Developers write primarily in Java.
Features of Android: Some of the basic features of Android are Application Framework for reuse and replacement of parts possible, Dalvik Virtual Machine for mobile devices Integrated browser, optimized graphics, SQLite for structured data storage, mobile telephony, Bluetooth, EDGE, 3G and Wi optimized camera-Fi, GPS, compass and accelerometer, rich development environment with device emulator, tools for debugging, memory and performance profiling, and a plug-in for the Eclipse IDE.
The development application for Android: Following the acquisition of basic knowledge about Android and its components, and if you want an Android phone of your own development, you must first install the various tools and IDE to start your project.
Here of the list :
SDK (software development Kit)
The Android Software Development Kit (SDK) contains a comprehensive set of development tools. These include a debugger, libraries, a handset emulator (based on QEMU), documentation, sample code and tutorials. Download from here
IDE (Integrated Development Environment)
After installing the SDK provided with the steps you need to install a suitable development environment like Eclipse, Eclipse 3.2, 3.3 (Europe), Android Development Tools plugin (optional).
Native Development Kit
The Android NDK is a companion tool to the Android SDK, you build performance-critical components of your application in native code allows. It provides headers and libraries on the business, handle user input, use of hardware sensors, access times, application resources and much more possible to program in C or C + +. If you write native code, your applications are still in one. Apk file, packaged, and they still run in a virtual machine on the device. The basic Android application model does not change. Download from here.
App Inventor for Android
App Inventor Android a web-based visual development environment for beginning programmers to create blocks MIT Java library and access to Android devices’ GPS, accelerometers and orientation data, functions of the phone, SMS open, speech-to-text conversion is based, contact, durable storage and Web services.
After installing these applications on your system, you are ready to develop an Android application to your Eclipse IDE. Basically, Java developers for writing.
Start your development: Android applications can use the same tools you already have installed. Android core libraries are you with the features needed for a high quality rich mobile applications to offer, while the development of tools for debugging, implementation and testing of your applications are much easier to build. More info here
Developer Toolbox
The developer toolbox module will guide you through how to help you write code that most of the systems makes android features, allowing you to create custom components and really coming to grips with the many API. More info here
For any further assistance you can take the reference Installing Android SDK here