Knowing the Name of Your Main Class Currently (Kotlin since M14 including up to 1.0 betas), to run a Kotlin class you are actually running a special class that is created at the file level that hold your main() and other functions that are top-level (outside of a class or interface). So if your code … Read more
Adding @Suppress(“UNCHECKED_CAST”) (also possible through IDEA’s Alt+Enter menu) to any of statement, function, class and file should help. Before: After:
You could call toInt() on your String instances: fun main(args: Array<String>) { for (str in args) { try { val parsedInt = str.toInt() println(“The parsed int is $parsedInt”) } catch (nfe: NumberFormatException) { // not a valid int } } } Or toIntOrNull() as an alternative: for (str in args) { val parsedInt = str.toIntOrNull() … Read more
Here is a version that does not use a plugin, more like the Groovy version. import org.gradle.jvm.tasks.Jar val fatJar = task(“fatJar”, type = Jar::class) { baseName = “${project.name}-fat” manifest { attributes[“Implementation-Title”] = “Gradle Jar File Example” attributes[“Implementation-Version”] = version attributes[“Main-Class”] = “com.mkyong.DateUtils” } from(configurations.runtime.map({ if (it.isDirectory) it else zipTree(it) })) with(tasks[“jar”] as CopySpec) } tasks … Read more
Extension functions are useful in a few cases, and mandatory in others: Idiomatic Cases: When you want to enhance, extend or change an existing API. An extension function is the idiomatic way to change a class by adding new functionality. You can add extension functions and extension properties. See an example in the Jackson-Kotlin Module … Read more
All these functions are used for switching the scope of the current function / the variable. They are used to keep things that belong together in one place (mostly initializations). Here are some examples: run – returns anything you want and re-scopes the variable it’s used on to this val password: Password = PasswordGenerator().run { … Read more
When button finds tap event, it marks it as consumed, which prevents other views from receiving it. This is done with consumeDownChange(), you can see detectTapAndPress method where this is done with Button here To override the default behaviour, you had to reimplement some of gesture tracking. List of changes comparing to system detectTapAndPress: I … Read more
val fileContent = MySpec::class.java.getResource(“/html/file.html”).readText()
Here are a few variations, depending on what style you will want to use, if you have everything of same or different types, and if the list unknown number of items… Mixed types, all must not be null to calculate a new value For mixed types you could build a series of functions for each … Read more
This is unsafe nullable type (T?) conversion to a non-nullable type (T), !! will throw NullPointerException if the value is null. It is documented here along with Kotlin means of null-safety.