class

  1. startActivity( Intent(this,KotlinType::class.java))

java 引用 class ，直接类名.class 。但是kt 需要 类名::class.java

新建kt项目报红

Cannot access ‘androidx.activity.context aware.Context Aware’ which is a supertype of ‘com.example.kotlinpractice.MainActivity’. Check your module classpath for missing or conflicting dependencies
image.png
添加依赖到 build.gradle，sync一下

  1.     def activity_version = "1.2.2"
  3.     // Java language implementation
  4.     implementation "androidx.activity:activity:$activity_version"
  5.     // Kotlin
  6.     implementation "androidx.activity:activity-ktx:$activity_version"

java调用kotlin注意事项

  1. apply plugin: 'kotlin-android'
  2. apply plugin: 'kotlin-android-extensions'