CS 175/286 - Lecture 2

Cay S. Horstmann

Lecture 2 Quiz 1

Put your answer into Piazza.

What is “detached mode” in Eclipse?

1. Executing a program without the debugger attached.
2. A view in a separate window.
3. A popup that shows content assistance.
4. A philosophical approach to contemplating the Eclipse framework.

Lecture 2 Quiz 2

What does the author least like about Eclipse?

1. The plugin architecture.
2. FindBugs.
3. Refactoring.
4. The Run As menu.

Today's Lecture

• Catch up with lab 1
• Just enough to do homework 1
• Layouts
• IDs
• Build Automation

Layouts

• Java Swing: Programmatic (e.g. GridBagLayout)
• HTML: Declarative
• Visual Basic: Drag and Drop
• Android: All of the above
• Easiest approach: Start with Drag and Drop
• Essential to look at the XML
• For now, just use RelativeLayout
• Pay attention to android:layout_below, android:layout_toRightOf

IDs

• Can specify TextView strings declaratively.
• Either with android:text="Fred" or with android:text="@string/main_character_name"
• Won't work when we need to update text dynamically.
• Assign an ID to each component
• Right-click in GUI builder
• In XML, set android:id="@+id/questionText"
• Get ID as R.id.questionText in Java code

  TextView t = (TextView) findViewById(R.id.questionText);
  t.setText("How old is Fred?");
  

Build Automation

• Reproducible builds happen outside Eclipse
• These days, generally on a build server
• Android uses Ant for build automation
• Make a build script build.xml with

  android update project --target android-8 --path .

  (Need ~/adt-bundle-linux-x86-20130522/sdk/tools/ on the PATH)
• Fire up the emulator:

  android avd &

• To build and run:

  ant debug install
  adb shell am start -n packageName/.MainActivity

  (Need ~/apache-ant-1.9.2/bin on the PATH)

Reading Before Next Class

• Programming Android Ch.3 Concurrency in Android until the end of AsyncTask and the UI Thread (not including Threads in an Android Process)

Lab

• Bring your laptop to each class
• You will work with a buddy
• One of you writes code, the other types up answers
• Switch roles each lab
• Submit lab work to github

Quiz Question

Goal: Android application that displays a quiz question, like this:

Layout

1. Make a new project with application and project name lab02 in the package edu.sjsu.cs175.lab02. Remember to put the project into ~/cs175/lab02, not inside the workspace.
2. Using the graphical layout builder, set up the question text and four answers.
3. When I did this, I got XML with messy alignment. I wanted the buttons below each other, and each option to the right of its button, aligned on the baseline. I had to fix up a couple of them, and it's pretty likely you will need to do the same. Explain the changes that you made.
4. Why did you get warning triangles next to each text view? (You don't need to fix them now.)
5. Run your application. What happens?
6. Now let's set the strings programmatically, not with the UI builder. Add code to set each textfield so that a different question and different options are displayed. How did you do this?

Build Automation

• Type javac -version on the command line. What do you get?
• Download Ant from here. Uncompress into your home directory. Add ~/apache-ant-1.9.2/bin and ~/adt-bundle-linux-x86-20130522/sdk/tools/ to your PATH. At the end of your .bashrc, add

  PATH=~/apache-ant-1.9.2/bin:~/adt-bundle-linux-x86-20130522/sdk/tools:$PATH

  Close the terminal window.
• Open a new terminal window. Type ant. What happens?
• Type android avd &. What happens?
• Type

  cd cs175/lab02
  android update project --target android-8 --path .
  ant debug install

  What happens?
• Run adb shell am start -n edu.sjsu.cs175.lec02/.MainActivity. What happens?