How to override method when instantiating object in Kotlin?

Question

In Java, to override method when instantiating new object we can do this

public ActivityTestRule<MainActivity> rule = new ActivityTestRule<MainActivity>(             MainActivity.class) {         @Override         protected void beforeActivityLaunched() {             // implement code             super.beforeActivityLaunched();         }     }; 

How to do that in Kotlin? I tried this code but it failed to compile.

@Rule @JvmField var rule = ActivityTestRule<MainActivity>(MainActivity::class.java) {     override fun beforeActivityLaunched() {         super.beforeActivityLaunched()     } }  

Answer 1

If you want to create anonymous inner class, you should use object.

var rule = object : ActivityTestRule<MainActivity>(MainActivity::class.java) {     override fun beforeActivityLaunched() {         super.beforeActivityLaunched()     } } 

See also Object Expressions and Declarations.