Simulation is a very powerful tool to understand how the device will work .Before start any project, it is a good practice to simulate it and virtually verify that works. Proteus is a simulation software.By using this software Arduino and Bluetooth module can be simulate.
1-Arduino IDE
you can download from
https://www.arduino.cc/en/Main/Software
2-Proteus isis software
you can download from
installing
3- Arduino library for Proteus
4- Bluetooth library for Proteus
How to add Arduino and Bluetooth Library in to Proteus
You can use this application on android smartphone or tablet with Bluetooth support.
(make sure that you have already enabled the "unknown sources" from security settings to install this apk)
If you want to learn how to make an Android APP check my tutorial
First choice by using COMPIM model that is a Physical Interface Model
in this case you don't have to use Bluetooth module library
Second choice by using Bluetooth module library