To Lecture Notes

IT 372 -- May 1, 2024

Review Questions

  1. What are the options for writing to the Logcat window with the Log class?
  2. How is an Intent object used?
  3. Set up a ConstraintLayout form to input grocery item data with these fields: description (String), code (int), and price (double). Also include a checkbox widget for on sale. When the Submit Grocery Item button is clicked, contatenate the information to the String variable groceryItems that is displayed on a new activity. Answer:
         activity_main.xml  MainActivity.java
         activity_display_items.xml  DisplayItemsActivity.java
    When the virtual device is rotated, save the groceryItems variable in a Bundle object so that this variable can be restored when the activity is recreated after the activity is destroyed due to device rotation.
    Answer: Main activity after adding onSaveInstanceState method and statements in onCreate to restore bundle.
         MainActivity.java

The Android Studio IDE

Practice Problem

  1. Create an app named ShowSuit. Add a radiobutton group with four radio buttons and an ImageView widget to the ConstraintLayout. Set the text for the radio buttons to Club, Diamond, Heart, and Spade. Set up an onCheckedChangeListener event handler that changes the image of the imageview to club.png, diamond.png, heart.png, or spade.png, depending on the radiobutton that is clicked. Here is a zipfile of the suit images.  Use an anonymous inner class to set up the event handler.
    Answer: Copy the suit images files into the res/drawable folder. Here are the layout and activity files. Also, see the ShowSuit Example for a different implementation of this problem.

The weight Attribute

Android Platform

Debugging Android Apps

Android Platform and Architecture

Adding Widgets Dynamically

Responding to Touch Events