class MainActivity : AppCompatActivity() {

val disposable = CompositeDisposable()

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    button.setOnClickListener {
        val f = TestPopup()
        usingRxJava(f)
        //usingLiveData(f)
    }
}

private fun usingRxJava(f: TestPopup) {
    val subject = SingleSubject.create<String>()
    f.show(supportFragmentManager, "TAG")
    button.post {
        f.dialog.setOnDismissListener {
            val str = f.arguments?.getString(TestPopup.TEST_KEY) ?: ""
            subject.onSuccess(str)
        }
    }
    subject.subscribe({
        Toast.makeText(this, "Accept : $it", Toast.LENGTH_SHORT).show()
    }, {

    }).addTo(disposable)
}

private fun usingLiveData(f: TestPopup) {
    val liveData = MutableLiveData<String>()
    f.show(supportFragmentManager, "TAG")
    button.post {
        f.dialog.setOnDismissListener {
            val str = f.arguments?.getString(TestPopup.TEST_KEY) ?: ""
            liveData.postValue(str)
        }
    }
    liveData.observe(this, Observer {
        Toast.makeText(this, "Accept : $it", Toast.LENGTH_SHORT).show()
    })
}

override fun onDestroy() {
    disposable.dispose()
    super.onDestroy()
}
}

class TestPopup : DialogFragment() {

override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
    return inflater.inflate(R.layout.dialog_test, container, false)
}

override fun onActivityCreated(savedInstanceState: Bundle?) {
    super.onActivityCreated(savedInstanceState)
    button_test.setOnClickListener {
        val arg = Bundle()
        arg.putString(TEST_KEY, edit_test.text.toString())
        arguments = arg
        dismiss()
    }
}

companion object {
    const val TEST_KEY = "KEY"
}
}

override fun onActivityCreated(savedInstanceState: Bundle?) {
    super.onActivityCreated(savedInstanceState)
    button_test.setOnClickListener {
        val input = edit_test.text.toString()
        (activity as MyListener).inputComplete(input)
        dismiss()
    }
}

class MainActivity : AppCompatActivity(), TestPopup.MyListener {

override fun inputComplete(input: String) {
    Toast.makeText(this, "Accept : $input", Toast.LENGTH_SHORT).show()
}
}

//MainViewModel.kt
class MainViewModel: ViewModel() {

    val dialogText = PublishProcessor.create<String>()

    fun postNewDialogText(text: String) {
        dialogText.onNext(text)
    }
}

// Activity
val disposable = CompositeDisposable()

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    val viewModel = ViewModelProviders.of(this).get(MainViewModel::class.java)

    viewModel.dialogText.subscribe {
        Toast.makeText(this, "Accept : $it", Toast.LENGTH_SHORT).show()
    }.addTo(disposable)

    button.setOnClickListener {
        TestPopup().show(supportFragmentManager, "TAG")
        // usingRxJava(f)
        // usingLiveData(f)
    }
}

override fun onDestroy() {
    disposable.dispose()
    super.onDestroy()
}

// Dialog Fragment
override fun onActivityCreated(savedInstanceState: Bundle?) {
    super.onActivityCreated(savedInstanceState)

    // Important!! use activity when getting the viewmodel.
    val viewModel = ViewModelProviders.of(requireActivity()).get(MainViewModel::class.java)

    button_test.setOnClickListener {
        viewModel.postNewDialogText(edit_test.text.toString())
        dismiss()
    }
}