ui基本完毕，修了一大把的bug

Assets/scripts/settings/controllerSettings.cs

@@ -37,6 +37,7 @@ public class controllerSettings : MonoBehaviour
     private const float NoteSpeedMin = 0.5f;
     private const float NoteSpeedMax = 2f;
     private const string NoteSpeedPrefKey = "noteSpeedMultiplier";
+    private const float NoteSpeedDefault = 1.0f;
 
     // continuous change
     private Coroutine continuousChangeCoroutine = null;
@@ -77,7 +78,8 @@ public class controllerSettings : MonoBehaviour
         {
             noteSpeedMultipler_slider.minValue = NoteSpeedMin;
             noteSpeedMultipler_slider.maxValue = NoteSpeedMax;
-            float saved = PlayerPrefs.GetFloat(NoteSpeedPrefKey, 1.0f);
+            EnsureDefaultNoteSpeedPreference();
+            float saved = PlayerPrefs.GetFloat(NoteSpeedPrefKey, NoteSpeedDefault);
             saved = Mathf.Clamp(saved, NoteSpeedMin, NoteSpeedMax);
             noteSpeedMultipler_slider.value = saved;
             UpdateNoteSpeedText(saved);
@@ -494,9 +496,20 @@ public class controllerSettings : MonoBehaviour
     private void ResetNoteSpeed()
     {
         if (noteSpeedMultipler_slider == null) return;
-        noteSpeedMultipler_slider.value = 1.0f; // triggers change and save
-        SaveNoteSpeedValue(1.0f);
-        UpdateNoteSpeedText(1.0f);
+        noteSpeedMultipler_slider.value = NoteSpeedDefault; // triggers change and save
+        SaveNoteSpeedValue(NoteSpeedDefault);
+        UpdateNoteSpeedText(NoteSpeedDefault);
+    }
+
+    private static void EnsureDefaultNoteSpeedPreference()
+    {
+        if (PlayerPrefs.HasKey(NoteSpeedPrefKey))
+        {
+            return;
+        }
+
+        PlayerPrefs.SetFloat(NoteSpeedPrefKey, NoteSpeedDefault);
+        PlayerPrefs.Save();
     }
 
     private void AddButtonContinuousEvents(Button btn, float delta)