Open Web's Intro to Android Workshop Spring 2018

Basic Outline

1. Start Android Studio, Create new Project
   • Briefly explain the IDE/simulator
2. Go to activity_main.xml, explain difference between Text vs. Design view
   • Explain layout (currently uses RelativeLayout, we could probably use ConstraintLayout)
   • Add EditText for entering the Bill total
   • Add SeekBar for controlling tip amount
     • Set the min at 0, max at 100, and initial progress at 18 (for 18% tip)

       android:min="0"
       android:progress="18"
       android:max="100"
       

   • Add three TextViews
     • One for showing tip percentage as the user moves the SeekBar
     • One for showing the actual tip amount in dollars
     • One for showing the final total
   • Add a Button for navigating to the SplitActivity
3. Go to MainActivity.java
   • Add binding for the components in XML (i.e. EditText, SeekBar, etc)
   • Add double variables for tip, bill total, final total

     private double billTotal;
     private double tip;
     private double total;
     

   • Add event listener for SeekBar
     • tipSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {...
     • Add logic within event handler to update textviews based on tip percentage being changed
   • Add event listener for bill total EditText
     • totalEditTxt.addTextChangedListener(new TextWatcher() {...
     • Add logic within event handler to update textviews based on bill total being changed
   • Add event listener for button to navigate to SplitActivity
4. Create a new Activity SplitActivity. Go to the XML and...
   • Add EditText for entering the number of people in the party
   • Add three TextViews
     • One for showing the original bill, split between the party
     • One for showing the tip total, split between the party
     • One for showing the final total, split between the party
5. Go to SplitActivity.java
   • Add binding for the components in XML (i.e. EditText, TextView, etc)
   • Add double variables for tip, bill total, final total from the first Activity and variables for current activity to compute the split

     private double billTotal, tipTotal, finalTotal;
     private int numPeople;
     private double billPerPerson, tipPerPerson, totalPerPerson;
     

   • Add event listener for number of people EditTxt
     • totalEditTxt.addTextChangedListener(new TextWatcher() {...
     • Add logic within event handler to update textviews based on the number of people changing
   • Add event listener for done button
     • doneBtn.setOnClickListener(new View.OnClickListener() {...
     • Add logic within event handler to go back to first activity if user is finished
6. Refactor event handler code with new methods so that repeated code can be removed