Java Fundamentals, HW 14 - Java & Android

You are given a work-in-progress binary calculator app. All of the UI has been done but it's missing code!

Here's a screenshot of the app:

The calculator can only work with binary numbers and only has one operation: add.

Apart from that the calculator works as you would expect - there's a standard text display on the top showing current input, a CLR button that resets the state completely, you can sum two (binary) numbers and the user can even chain multiple additions by pressing the + button instead of =.

Hint: No UI changes are necessary, all of the work should be done in CalculatorActivity.

Requirements

• Pressing 0 or 1 must be immediately reflected in the text display

• After pressing + the user must be able to input a new number

• Inputting a number, pressing +, inputting another number and then pressing = must display the (correct) sum

• The user must be able to keep chaining additions with +, i.e. the following must work:
  • Input 100
  • Press +
  • Input 10
  • Press + <-- calculator displays 110
  • Input 1
  • Press + <-- calculator displays 111
  • Input 1
  • Press = <-- calculator displays 1000

• CLR completely resets the calculator to the initial state

• Additions with up to 16-digit binary numbers must be supported
• Handling invalid input is completely up to you

Submitting

For your convenience, we have set up a Gradle task to ZIP up all files in your project folder so it is easy for you to attach it to an e-mail and send it our way. All you need to do is to execute one of the following commands (depending on your OS) in your project folder:

Linux / OSX:

./gradlew clean deploy --console=plain

Windows:

gradlew clean deploy --console=plain

It will ask you for your full name, Student Book Number (also known as matrikli number), homework number and a comment (optional).

Example (OSX):

$ ./gradlew clean deploy --console=plain
Incremental java compilation is an incubating feature.
:clean
:gatherHwProps

Your full name (e.g. John Smith):
Jane Smith
Your Student Book Number (matrikli number, e.g. B12345):
B12345
Homework number:
14
Comment:
for the lulz
:deploy
Built zip /Users/madis/Code/jf-hw-android-calculator/build/jf-homework-B12345-14.zip

BUILD SUCCESSFUL

Total time: 17.082 secs

After Gradle has finished, you can find the generated ZIP file in build folder with name such as jf-homework-B12345-14.zip (it contains your Student Book Number/matrikli number and homework number).

Attach the ZIP to an e-mail and send it our way, to jf@zeroturnaround.com.