如何在Kotlin中实例化对象时覆盖方法？

Question

在Java中，要在实例化新对象时覆盖方法，我们可以这样做

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

如何在Kotlin做到这一点？我尝试了这段代码，但无法编译。

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

Answer 1

如果要创建匿名内部类，则应使用object。

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

另见Object Expressions and Declarations。