Anko Kotlin Library

Anko is a library designed to make Android development faster and cleaner by providing helpers for the Android SDK. It is divided into four main parts:

1. Anko Commons: Helpers for Intents, Dialogs, Toasts, Logging, and Resources.
2. Anko Layouts: A DSL for writing dynamic, type-safe Android layouts without XML.
3. Anko SQLite: A query DSL and parser for Android SQLite.
4. Anko Coroutines: Utilities based on kotlinx.coroutines.

Anko Coroutines provides utilities built on top of kotlinx.coroutines:

• bg(): Executes code in a common pool.
• asReference(): Creates a weak reference wrapper. This protects against memory leaks in asynchronous frameworks that do not support cancellation by preventing coroutines from holding strong references to captured objects until they finish or are canceled.

When using Anko's layout DSL helpers, properties are mapped to Android widget methods. The helper constructors use Java-style type notation: primitive types are lowercase (e.g., int, boolean) and nullable types do not use question marks (e.g., CharSequence instead of CharSequence?).

Common property mappings include:

• Button / CheckBox / TextView / EditText: Use text with CharSequence or int (for resource IDs).
• CheckBox: Also supports a checked property of type boolean.
• ImageView / ImageButton: Use imageDrawable with type Drawable or imageResource with type int.

You can include Anko in your Android project using Gradle. You can either use the meta-dependency to include all features at once, or include specific modules to keep your project lightweight.

Note: Anko is deprecated.

// To include all features (Commons, Layouts, SQLite, Coroutines)
dependencies {
    implementation "org.jetbrains.anko:anko:$anko_version"
}

ext.anko_version='0.10.8'

Anko is officially deprecated. Depending on which part of the Anko library you were using, you should migrate to the following modern alternatives:

Layout DSL

If you used Anko Layouts for building Android layouts via a type-safe DSL, migrate to:

• Jetpack Compose: A reactive View DSL for Kotlin, backed by Google.
• Splitties (Views DSL): An extensible View DSL that resembles the Anko experience.

Generic utilities

If you used Anko Commons for utility functions and classes, migrate to:

• Android KTX: A set of Kotlin extensions for various Android purposes, backed by Google.
• Splitties: A collection of micro-libraries for various use cases.

SQLite helpers

If you used Anko SQLite for database access, migrate to:

• Room: An annotation-based framework for SQLite database access, backed by Google.
• SQLDelight: A type-safe API generator for SQL queries.

Anko SQLite simplifies working with Android SQLite databases by providing a query DSL and parser collection, removing the need to manually parse results using Android cursors.

fun getUsers(db: ManagedSQLiteOpenHelper): List<User> = db.use {
    db.select("Users")
            .whereSimple("family_name = ?", "John")
            .doExec()
            .parseList(UserParser)
}

Anko Layouts provides a type-safe DSL for writing dynamic Android layouts without XML. It supports standard layouts like verticalLayout and specialized layouts like ConstraintLayout (since v0.10.4).

Listeners like onClick accept suspend lambdas, allowing you to write asynchronous code directly within the UI definition.

verticalLayout {
    val name = editText()
    button("Say Hello") {
        onClick { toast("Hello, ${name.text}!") }
    }
}

The following list defines the available property signatures used by Anko's layout DSL helpers. Note that types follow Java conventions (lowercase primitives, no question marks for nullables).

android.widget.Button text:CharSequence
android.widget.Button text:int
android.widget.CheckBox text:CharSequence
android.widget.CheckBox text:int
android.widget.CheckBox text:CharSequence, checked:boolean
android.widget.CheckBox text:int, checked:boolean
android.widget.TextView text:CharSequence
android.widget.TextView text:int
android.widget.EditText text:CharSequence
android.widget.EditText text:int
android.widget.ImageView imageDrawable:Drawable
android.widget.ImageView imageResource:int
android.widget.ImageButton imageDrawable:Drawable
android.widget.ImageButton imageResource:int

To create a dialog that presents a list of items for the user to select, use the items or adapter methods. These methods require a callback that receives the index (which) of the selected item.

Using a List of Strings

items(listOf("Option 1", "Option 2", "Option 3")) { which -> 
    // 'which' is the index of the selected item
}

Using an Android Resource Array

items(R.array.my_options_array) { which -> 
    // 'which' is the index of the selected item
}

Using a ListAdapter or Cursor

• adapter(adapter: ListAdapter, callback: (which: Int) -> Unit)
• adapter(cursor: Cursor, labelColumn: String, callback: (which: Int) -> Unit)

You can replace the standard dialog content with custom layouts using either a standard Android View or an Anko DSL block.

Using a standard View

customView(myViewInstance)

Using an Anko DSL block

This allows you to define the layout inline using Anko's UI DSL:

customView { 
    textView { text = "Custom Content" }
    button { text = "Click Me" }
}