fix poll validation (#1459)

app/src/main/java/com/keylesspalace/tusky/adapter/AddPollOptionsAdapter.kt

@@ -30,7 +30,7 @@ import com.keylesspalace.tusky.util.visible
 class AddPollOptionsAdapter(
         private var options: MutableList<String>,
         private val maxOptionLength: Int,
-        private val onOptionRemoved: () -> Unit,
+        private val onOptionRemoved: (Boolean) -> Unit,
         private val onOptionChanged: (Boolean) -> Unit
 ): RecyclerView.Adapter<ViewHolder>() {
 
@@ -70,7 +70,7 @@ class AddPollOptionsAdapter(
             holder.editText.clearFocus()
             options.removeAt(holder.adapterPosition)
             notifyItemRemoved(holder.adapterPosition)
-            onOptionRemoved()
+            onOptionRemoved(validateInput())
         }
     }
 

app/src/main/java/com/keylesspalace/tusky/view/AddPollDialog.kt

@@ -48,8 +48,9 @@ fun showAddPollDialog(
     val adapter = AddPollOptionsAdapter(
             options = poll?.options?.toMutableList() ?: mutableListOf("", ""),
             maxOptionLength = maxOptionLength ?: DEFAULT_MAX_OPTION_LENGTH,
-            onOptionRemoved = {
+            onOptionRemoved = { valid ->
                 view.addChoiceButton.isEnabled = true
+                dialog.getButton(AlertDialog.BUTTON_POSITIVE).isEnabled = valid
             },
             onOptionChanged = { valid ->
                 dialog.getButton(AlertDialog.BUTTON_POSITIVE).isEnabled = valid