interface CallBack {
  fun onSuccess(str: String)
  fun onFailure(code: Int)
}
class Worker {
  var callback: CallBack? = null
  fun done(str: String) {
    callback?.onSuccess(str)
  }

  fun fail(code: Int) {
    callback?.onFailure(code)
  }

  fun setCallBack(lis: CallBack) {
    callback = lis;
  }
}

 Worker().apply {
     setCallBack(object : CallBack {
      override fun onSuccess(str: String) {
      }
      override fun onFailure(code: Int) {
        toast("$code")
      }
    })
  }.fail(110)
//结果：吐司：110

public class SimCallBack implements CallBack{
  @Override
  public void onSuccess(@NotNull String str) {
  }
  @Override
  public void onFailure(int code) {
  }
}

 Worker().apply {
    setCallBack(object : SimCallBack() {
     override fun onFailure(code: Int) {
        super.onFailure(code)
        toast("$code")
     }
    })
}.fail(110)

 class SimpleCallBack : CallBack{
  private var _OnSucess: ((str: String) -> Unit)? = null
  fun success(listener: (str: String) -> Unit) {
    _OnSucess = listener
  }
  override fun onSuccess(str: String) {
    _OnSucess?.invoke(str)
  }
  private var _OnFailure: ((code: Int) -> Unit)? = null
  override fun onFailure(code: Int) {
    _OnFailure?.invoke(code)
  }
  fun fail(listener: (code: Int) -> Unit) {
    _OnFailure = listener
  }
}

 fun setCallBacker(listener: SimpleCallBack.() -> Unit) {
    var ca = SimpleCallBack()
    ca.listener()
    setCallBack(ca)
 }

 Worker().apply {
    setCallBacker {
      success { toast(it) }
      fail { }//若不需要，可以不显示声明
    }
 }.done("完成")
//结果：吐司:完成