CMPUT 301

Lab 3: More Android

1. Getting Started

1. Fork and clone this repository and open the /code folder in Android Studio.
2. You'll find a basic ListyCity app that displays a static list of cities and provinces.

2. Demo Instructions

During the lab demo, we'll implement "Add City" functionality:

1. Review Lab 3 Slides
2. Follow along with Lab 3 Instructions
3. Read about Code Conventions (see the Kotlin Code Conventions PDF).
4. By the end, you'll have implemented the ability to add new cities to the list.

3. Lab 3 Participation Exercise

Task

• Add functionality to ListyCity to allow editing existing cities. The design implementation is flexible and up to your creativity.
• Update the README.md and the LICENSE.md with your details.

Example Implementation

Note: Your app does NOT need to look exactly like the screenshots. The only requirement is the ability to edit an existing city.

4. Implementation Tips

1. City Class Updates

• The starter code uses a City data class with val properties:

data class City(
    val name: String,
    val province: String
)

Since name and province use val, they cannot be changed directly after a City object is created

To edit a city, create a new City object with the updated values and replace the old city in the list

Example:

val updatedCity = City(
    name = newCityName,
    province = newProvinceName
)

2. Choose Your Implementation

Recommended Approach:

• Track which City object is selected
• Store the edited city name and province in text fields
• Create a new City object with the updated values
• Replace the selected city in the list

Example Code

One approach is to add an updateCity() function to CityRepository:

fun updateCity(oldCity: City, updatedCity: City) {
    val index = _cities.indexOf(oldCity)
    if (index != -1) {
        _cities[index] = updatedCity
    }
}

Compose Hints

• Use state to track the selected city:

var selectedCity by remember { mutableStateOf<City?>(null) }

• A city row can be made selectable using Modifier.clickable { ... }
• Text fields can be reused to enter the updated city name and province
• Use a callback such as onUpdateCity(oldCity, updatedCity) to send the edit action upward

5. Submission

[!CAUTION] Make sure to commit and push your code to the GitHub repository before the deadline!

Once you completed, please go to Canvas and submit your Lab 3 GitHub repository link.

Due Date

Friday after the Thursday lab at 5 PM