Kotlin 覆盖方法中的 IllegalArgumentException

In Kotlin I'm overriding this two Google Sign-In functions:

override fun onConnectionFailed(result: ConnectionResult) {
        if (result.hasResolution()) {
            try {
                result.startResolutionForResult(this, RESOLVE_CONNECTION_REQUEST_CODE)
            } catch (e: IntentSender.SendIntentException) {
                // Unable 到 resolve, message user appropriately
            }

        } else {
            val gaa = GoogleApiAvailability.getInstance()
            gaa.getErrorDialog(this, result.errorCode, 0)
        }
    }

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent) {
        when (requestCode) {
            RESOLVE_CONNECTION_REQUEST_CODE -> if (resultCode == Activity.RESULT_OK) {
                mGoogleApiClient!!.connect()
            }
        }
    }

到 check if the connection 到 google fails.

The problem is that sometimes, when I dismiss the dialog containing user accounts, which pop-up when the activity is launched

就像这个:

I'm getting an IllegalArgumentException with the following logcat

E/AndroidRuntime:致命异常:主

这就指向了onActivityResult函数.

我试着改变

requestCode: Int

到

requestCode: Int?

但是很明显，我得到了一个错误，因为该函数与它的超类中的函数不同.

我该怎么修？