Caused by: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.

[jhonatansabadi]

I am using Kotlin... And tried to use in code, but the app does not init, it get error on the first activty.

SwitchDateTimeDialogFragment.newInstance(
                "Escolha a data",
                "CONFIRMAR",
                "CANCELAR"
            ).apply {
                startAtCalendarView()
                set24HoursMode(true)
                setMinimumDateTime(Date())
                setDefaultDateTime(Date())
                setOnButtonClickListener(
                    object : SwitchDateTimeDialogFragment.OnButtonClickListener {
                        override fun onPositiveButtonClick(date: Date?) {
                            date?.let {
                                toast(it.toDateString())
                            }
                        }

                        override fun onNegativeButtonClick(date: Date?) {

                        }
                    })
                show(supportFragmentManager, "dialog_time")
            }

[J-Jamet]

Version 2.1 should solve this problem as it now inherits the theme material.