Go to Android Studio site and download the latest file. Some lower version is more stable depending on your computer requirement.
If you want latest Android Studio software too work well, your pc must be At east 4GB RAM.
Go to Oracle site and download java and and install it complete.
Download Emulator, if you are a beginner I will advise you use Genymotion.
If you want it for a business, you have to register one time $25 Google Play Store where you can upload your beauty Android Apps. Remember no matter how good the app in play store, you can still build better one.
How to design android currency converter.
1. Draw the sketch on how the app will look like. Here you are in-charge and the design is yours. Ensure the get the best out of it.
2. Design your UI. Here you are going to use xml and rock the app. Design is everything because some people like quality and only the look can make them keep the app.
Don’t design an app that somebody will need your help on how to use it.
3. Design the app function, you use java to design what the app will do. Ensure to use minimum size but achieve the great app.
Open you Android Studio and add this to your activity.
Add this to xml. You can choose your on design.
Design your logo.
Generate a sign app ready to be deployed to Google Play Store.