CSC 349: Week of 1/22/18

CSC 349: The Week beginning Jan. 22

Homework:

Read and summarize the following article Amazon Go debuts, and its prying cameras foil our shoplifting attempts

In the context of Android/Java programming define the following terms
- final
- @Override
- Gradle
- Kotlin
- package
- extends
- import
- AndroidManifest
Due: Jan. 30
Tuesday:

RestCalc_radio_button.zip

The activity_main.xml and MainActivity.java files for a revised version of the restaurant tip calculator app that uses radiobuttons to select the tip amount. Some features to notice
- In the layout, the RadioButtons and contained with a RadioGroup. The RadioGroup is a container and so has open and close tags; whereas RadioButtons are "singletons" and thus end with />
- The RadioButtons did not require constraints. Instead they were placed one under the other within the RadioGroup container.
- In MainActivity.java, we worked first with the RadioGroup
  final RadioGroup rgTip = (RadioGroup) findViewById(R.id.rgTip);
  int radio_id = rgTip.getCheckedRadioButtonId();
  
  and only then with the RadioButtons
  
  RadioButton myRad = (RadioButton) findViewById(radio_id);
- The id obtained from the RadioGroup is -1 if no RadioButton in the group is checked.
- We can use both the text and the tag properties of the RadioButtons
Day_Time_Radio_Demo.zip xml and java for an app that allows the user to choose a day and time via two sets of Radio buttons. New features:
- How to pre-select an item. (There seemed to be an xml approach to check a radio button ahead of time (in Design), but then my user could not seem to uncheck that option. Thus I ended up doing it in Java toward the end of onCreate
```
			View rg_child = rgDay.getChildAt(1);
			RadioButton my_radio_button =(RadioButton)rg_child;
			my_radio_button.setChecked(true);
		
```
- How to clear out the choices. At first I looped over the Radio buttons in each group and used .setChecked(false) but this made it difficult for the user to re-select the choice that had just been de-selected. Then I found the RadioGroup's clearCheck() which was simpler and worked better.
Lab: Cooking Steak
Design an app with two sets of radio buttons (each set in its own radio group). Also have a Button and a TextView.

The first set of radio buttons is for the user to choose the "doneness" (Rare, Medium Rare, Medium, Medium Well, Well).

The second set of radio buttons is for the user to choose the thickness in inches (1, 1.25, 1.5, 1.75, 2).

If the "doneness index" is 0 for Rare, 1 for Medium Rare, etc., then the cook time (in minutes) can be calculated as

cook_time = 2 + doneness_index + thickness * 2

When the user clicks the button, determine the doneness and thickness, then calculate and display the cook time.

If the user did not choose a doneness, display a Toast message. Similarly if the user did not choose a thickness, display a Toast message.

If the user changes the doneness or the thickness, then either remove your answer or recalculate your answer.

Zip up and submit the layout (e.g. activity_main.xml) and the java (e.g. MainActivity.java). Email that.

Due: Jan. 30
Thursday:

Spinners.zip These files come from an app that shows two types of spinners (think drop-down select). One spinner gets values from an array in the values.xml file that is part of resources (res). The other spinner gets values from an array declared in Java.

DumbNumberTrick.zip demonstrates the NumberPicker widget as well as the enabling and disabling on buttons.

Lab: Potato Calorie Count (source: https://www.verywell.com/how-many-calories-in-a-baked-potato-2506867)

Design an app that allows the user to determine the number of calories in a baked potato. The app will have two spinners (one for the size of the potato and one for the toppings), a button, and textview for displaying the answer. Have one spinner loaded from an array in an xml resource, and have the other spinner loaded from an array in Java.

Have a spinner that allows the user to enter the number of ounces of the baked potato. The range should go from 5 to 12. You can include half values if you want (5, 5.5, 6, ...). There are 25 calories for each ounce in a potato.

Have a spinner that allows the user to enter a topping. (Nothing, Butter, Sour Cream, Chili). Each of these will correspond to additional calories of (0, 100, 60, 75) respectively.

When the user clicks the button, determine the size of and topping on the potato and display the corresponding number of calories.

When the user changes either spinner value, either clear out the answer or recalculate.

Submit the .xml file with the array values, the .xml file for the layout, and the .java files (zipped up).

Due: Feb. 1