Alerts

A library allows you to show native alerts.
It shows AlertDialog on Android and UIAlertController on iOS.

Installing

This library is available on Maven Central. You can import Kaluga Alerts as follows:

repositories {  
    // ...
    mavenCentral()
}
// ...  
dependencies {  
    // ...
    implementation("com.splendo.kaluga:alerts:$kalugaVersion")
}

Usage

You can show an alert from shared code like this:

// Shared code  
fun showAlert(builder: AlertPresenter.Builder, title: String) = MainScope().launch {  
    // Create OK action
    val okAction = Alert.Action("OK") // POSITIVE/DEFAULT style
    // Create Cancel action
    val cancelAction = Alert.Action("Cancel", Alert.Action.Style.NEGATIVE)
    // Create an Alert with title, message and actions
    val alert = builder.buildAlert(this) {
        setTitle(title)
        setMessage("This is sample message")
        addActions(okAction, cancelAction)
    }
    // Show and handle action
    when (alert.show()) {
        okAction -> println("OK pressed")
        cancelAction -> println("Cancel pressed")
    }
}

Or this:

// Shared code  
fun showAlert(builder: AlertPresenter.Builder, title: String) = MainScope().launch {  
    // Create an Alert with title, message and actions
    val alert = builder.buildAlert(this) {
        setTitle(title)
        setPositiveButton("Yes") {
            println("yes pressed")
        }
        setNegativeButton("No") {
            println("No pressed")
        }
    }
    // Show
    alert.show()
}

In order to dismiss alert you can use dismiss() function:

MainScope().launch {
    // Build alert
    val alert = builder.buildAlert(this) {
        setTitle("Please wait...")
        setPositiveButton("OK")
    }
    // Show
    alert.showAsync()
    // Dismiss
    alert.dismiss()
}

Builder

The AlertPresenter.Builder class can be used to build Alerts.

Build alert

• buildAlert(coroutineScope: CoroutineScope, initialize: Alert.Builder.() -> Unit): BaseAlertPresenter — builder to create BaseAlertPresenter, thread-safe

Build action sheet

• buildActionSheet(coroutineScope: CoroutineScope, initialize: Alert.Builder.() -> Unit): BaseAlertPresenter — builder to create BaseAlertPresenter, thread-safe

Set title, style and message

• setTitle(title: String?) — sets optional title for the alert
• setMessage(message: String?) — sets an optional message for the alert

Set buttons

• setPositiveButton(title: String, handler: AlertActionHandler) — sets a positive button for the alert
• setNegativeButton(title: String, handler: AlertActionHandler) — sets a negative button for the alert
• setNeutralButton(title: String, handler: AlertActionHandler) — sets a neutral button for the alert

On Android you can have only maximum of 3 buttons (each of type Positive, Negative and Neutral) for the alert with Alert.Style.ALERT

Set actions for action sheet

• addActions(actions: List<Alert.Action>) or addActions(vararg actions: Alert.Action) — adds a list of actions for the alert

You can also show action sheet using Actions with handlers:

fun showList(builder: AlertPresenter.Builder) = MainScope().launch {
     builder.buildActionSheet(this) {
         setTitle("Select an option")
         addActions(
             Alert.Action("Option 1") { /* handle option #1 */ },
             Alert.Action("Option 2") { /* handle option #2 */ },
             Alert.Action("Option 3") { /* handle option #3 */ },
             Alert.Action("Option 4") { /* handle option #4 */ }
         )
     }.show()
}

On iOS you can have only 1 button with type of Action.Style.Cancel / Negative

Action styles

On Android actions can be: Positive, Negative and Neutral.
On iOS actions can be: Default, Cancel and Destructive.

Platform Specific Building

The AlertPresenter.Builder object should be created from the platform side.

Android

On Android the builder is an ActivityLifecycleSubscribable (see Architecture) that needs an ActivityLifecycleSubscribable.LifecycleManager object to provide the current context in which to display the alert. For BaseLifecycleViewModel, the builder should be provided to BaseLifecycleViewModel.activeLifecycleSubscribables (using the constructor or BaseLifecycleViewModel.addLifecycleSubscribables) and bound to a KalugaViewModelLifecycleObserver or ViewModelComposable.

class AlertViewModel: BaseLifecycleViewModel() {  
  
    val builder = AlertPresenter.Builder()
    
    init {
        addLifecycleSubscribables(builder)
    }
    
    fun show() {
            coroutineScope.launch {
                builder.build(this) {
                  // Presentation logic
                }.show()
            }
        }
}

And then in your Activity:

class MyActivity: KalugaViewModelActivity<AlertViewModel>() {  
  
    private val viewModel: AlertViewModel by viewModels()
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        viewModel.show()
    }
 }

For other usages, make sure to call ActivityLifecycleSubscribable.subscribe and ActivityLifecycleSubscribable.unsubscribe to manage the lifecycle manually.

// Android specific
MainScope().launch {
    val builder = AlertPresenter.Builder()
    builder.subscribe(activity)
    builder.buildAlert(this) {
        // Alert Logic
    }.show()
}

iOS

On iOS this builder should be instantiated with UIViewController:

// iOS specific
let builder = AlertPresenter.Builder(viewController)

Since a UIViewController is required, for SwiftUI the View displaying the Alert should have a UIViewControllerRepresentable wrapping the UIViewController associated with the AlertPresenter.Builder attached. The Kaluga SwiftUI scripts provide a ContainerView that offers this functionality out of the box (if the includeAlerts setting is set to true)

Testing

Use the test-utils-alerts module to get a mockable Alert Presenter.