fix: keyboard layout sometimes inadvertently backed to the default layout

Author: WhiredPlanck

app/src/main/java/com/osfans/trime/ime/keyboard/Event.kt

@@ -27,7 +27,7 @@ class Event(var s: String) {
     private var states: List<String>? = null
     var command: String = ""
     var option: String = ""
-    var select: String? = null
+    var select: String = ""
     private var toggle: String = ""
     var commit: String = ""
         private set

app/src/main/java/com/osfans/trime/ime/keyboard/KeyboardWindow.kt

@@ -265,7 +265,7 @@ class KeyboardWindow(
                 return
             }
             if (event.code == KeyEvent.KEYCODE_EISU) { // Switch keyboard
-                switchKeyboard(event.select ?: ".default")
+                switchKeyboard(event.select)
             } else {
                 delegate.onEvent(event)
             }

app/src/main/java/com/osfans/trime/ime/text/TextInputManager.kt

@@ -225,10 +225,10 @@ class TextInputManager(
             }
             KeyEvent.KEYCODE_LANGUAGE_SWITCH -> { // Switch IME
                 when {
-                    event.select!!.contentEquals(".next") -> {
+                    event.select == ".next" -> {
                         trime.switchToNextIme()
                     }
-                    !event.select.isNullOrEmpty() -> {
+                    event.select.isNotEmpty() -> {
                         trime.switchToPrevIme()
                     }
                     else -> {