Exercise: GUI View Hierarchy Simulation
Implement the following classes and methods, that will represent a view hierarchy in a GUI system:
- Create an open class
Viewwith primary constructor properties: read-onlyidof typeStringand read-writeisVisibleof typeBoolean. - Implement methods
showandhidein theViewclass, that will change theisVisibleproperty totrueandfalserespectively. - Create two subclasses of
View:TextViewandToggle. TextViewshould have a constructor with parameteridand propertytext, that will represent the text displayed in the view. It should set superclassisVisibleproperty totrue.Toggleshould have a constructor with parameterid. It should set superclassisVisibleproperty totrue.Toggleshould have an additional propertyisOn, that will represent the state of the toggle. It should be initially set tofalse.Toggleshould have a methodclick, that will change theisOnproperty to the opposite state.
Example usage:
val view = View(
id = "v1",
isVisible = false,
)
println(view.id) // v1
println(view.isVisible) // false
val textView = TextView(
id = "tv1",
text = "Hello, World!",
)
println(textView.id) // tv1
println(textView.text) // Hello, World!
println(textView.isVisible) // true
textView.text = "Welcome to Kotlin!"
println(textView.text) // Welcome to Kotlin!
textView.hide()
println(textView.isVisible) // false
val toggle = Toggle(
id = "toggle1",
)
println(toggle.id) // toggle1
println(toggle.isOn) // false
toggle.click()
println(toggle.isOn) // true
println(toggle.isVisible) // true
toggle.hide()
println(toggle.isVisible) // false
toggle.show()
println(toggle.isVisible) // true
This problem can either be solved in the below playground or you can clone kotlin-exercises project and solve it locally. In the project, you can find code template for this exercise in essentials/classes/Gui.kt. You can find there example usage and unit tests.
Once you are done with the exercise, you can check your solution here.
Playground
import junit.framework.TestCase.assertFalse
import junit.framework.TestCase.assertTrue
import org.junit.Test
import kotlin.test.assertEquals
// TODO
fun main() {
val view = View(
id = "v1",
isVisible = false,
)
println(view.id) // v1
println(view.isVisible) // false
val textView = TextView(
id = "tv1",
text = "Hello, World!",
)
println(textView.id) // tv1
println(textView.text) // Hello, World!
println(textView.isVisible) // true
textView.text = "Welcome to Kotlin!"
println(textView.text) // Welcome to Kotlin!
textView.hide()
println(textView.isVisible) // false
val toggle = Toggle(
id = "toggle1",
)
println(toggle.id) // toggle1
println(toggle.isOn) // false
toggle.click()
println(toggle.isOn) // true
println(toggle.isVisible) // true
toggle.hide()
println(toggle.isVisible) // false
toggle.show()
println(toggle.isVisible) // true
}
class GuiTests {
@Test
fun `view show should set isVisible to true`() {
val view = View("view1", false)
view.show()
assertTrue(view.isVisible)
}
@Test
fun `view hide should set isVisible to false`() {
val view = View("view2", true)
view.hide()
assertFalse(view.isVisible)
}
@Test
fun `toggle click should toggle isOn state`() {
val toggle = Toggle("toggle1")
toggle.click()
assertTrue(toggle.isOn)
toggle.click()
assertFalse(toggle.isOn)
}
@Test
fun `text view setText should update text property`() {
val textView = TextView("textView1", "Hello")
textView.text = "World"
assertEquals("World", textView.text)
}
@Test
fun `toggle should inherit properties from view`() {
val toggle = Toggle("toggle2")
assertTrue(toggle.isVisible)
toggle.hide()
assertFalse(toggle.isVisible)
}
@Test
fun `text view should inherit properties from view`() {
val textView = TextView("textView2", "Hello")
assertTrue(textView.isVisible)
}
@Test
fun `toggle should start with isOn set to false`() {
val toggle = Toggle("toggle3")
assertFalse(toggle.isOn)
}
@Test
fun `toggle should toggle isOn state correctly`() {
val toggle = Toggle("toggle4")
toggle.click()
assertTrue(toggle.isOn)
toggle.click()
assertFalse(toggle.isOn)
toggle.click()
assertTrue(toggle.isOn)
}
@Test
fun `view show and hide interactions`() {
val view = View("view3", false)
view.show()
assertTrue(view.isVisible)
view.hide()
assertFalse(view.isVisible)
}
@Test
fun `text view setText and visibility interactions`() {
val textView = TextView("textView3", "Hello")
textView.text = "World"
assertEquals("World", textView.text)
textView.hide()
assertFalse(textView.isVisible)
}
}
