diff --git a/app/src/main/java/com/ray650128/gstreamer_demo_app/Constants.kt b/app/src/main/java/com/ray650128/gstreamer_demo_app/Constants.kt
new file mode 100644
index 0000000..310ef47
--- /dev/null
+++ b/app/src/main/java/com/ray650128/gstreamer_demo_app/Constants.kt
@@ -0,0 +1,5 @@
+package com.ray650128.gstreamer_demo_app
+
+object Constants {
+    const val CONF_DELAY_BASE_MILLIS = 300L
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/ray650128/gstreamer_demo_app/ui/mainScreen/MainActivity.kt b/app/src/main/java/com/ray650128/gstreamer_demo_app/ui/mainScreen/MainActivity.kt
index d5c7128..58f46b2 100644
--- a/app/src/main/java/com/ray650128/gstreamer_demo_app/ui/mainScreen/MainActivity.kt
+++ b/app/src/main/java/com/ray650128/gstreamer_demo_app/ui/mainScreen/MainActivity.kt
@@ -8,6 +8,7 @@ import android.view.WindowManager
 import androidx.activity.viewModels
 import androidx.appcompat.app.AppCompatActivity
 import androidx.viewpager2.widget.ViewPager2
+import com.ray650128.gstreamer_demo_app.Constants
 import com.ray650128.gstreamer_demo_app.R
 import com.ray650128.gstreamer_demo_app.databinding.ActivityMainBinding
 import com.ray650128.gstreamer_demo_app.model.Device
@@ -55,6 +56,34 @@ class MainActivity : AppCompatActivity() {
             offscreenPageLimit = 1
             setPageTransformer(null)
             registerOnPageChangeCallback(object: ViewPager2.OnPageChangeCallback() {
+                private var oldPage = 0
+                override fun onPageScrollStateChanged(state: Int) {
+                    super.onPageScrollStateChanged(state)
+                    if (state == ViewPager2.SCROLL_STATE_DRAGGING) {
+                        oldPage = currentPage
+                        splitVideoViewAdapter.stop(currentPage)
+                    }
+                    if (state == ViewPager2.SCROLL_STATE_IDLE && currentPage == oldPage) {
+                        splitVideoViewAdapter.play(currentPage)
+                    }
+                    Log.d("Split", "onPageScrollStateChanged: ${
+                        when(state) {
+                            ViewPager2.SCROLL_STATE_IDLE -> "SCROLL_STATE_IDLE"
+                            ViewPager2.SCROLL_STATE_DRAGGING -> "SCROLL_STATE_DRAGGING"
+                            ViewPager2.SCROLL_STATE_SETTLING -> "SCROLL_STATE_SETTLING"
+                            else -> ""
+                        }
+                    }")
+                    Log.d("Split", "oldPage: $oldPage, currentPage: $currentPage")
+                }
+                override fun onPageScrolled(
+                    position: Int,
+                    positionOffset: Float,
+                    positionOffsetPixels: Int
+                ) {
+                    super.onPageScrolled(position, positionOffset, positionOffsetPixels)
+                    Log.d("Split", "onPageScrolled: $currentPage")
+                }
                 override fun onPageSelected(position: Int) {
                     super.onPageSelected(position)
                     currentPage = position
@@ -102,7 +131,7 @@ class MainActivity : AppCompatActivity() {
         for (i in 0 until splitVideoViewAdapter.itemCount) {
             splitVideoViewAdapter.stop(i)
         }
-        delay(oldSplitMode * 500L)
+        delay(oldSplitMode * Constants.CONF_DELAY_BASE_MILLIS)
         oldSplitMode = splitMode
         splitVideoViewAdapter.clear()
         // 如果群組內沒有裝置，則顯示底圖
@@ -119,7 +148,7 @@ class MainActivity : AppCompatActivity() {
                 splitVideoViewAdapter.add(i, splitFragment)
             }
             currentPage = 0
-            binding.viewPager.currentItem = 0
+            //binding.viewPager.currentItem = 0
         }
     }