diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 3b5a07d..c0683c0 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -3,6 +3,7 @@
     package="com.ray650128.gstreamer_demo_app">
 
     <application
+        android:name=".MyApplication"
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"
diff --git a/app/src/main/java/com/ray650128/gstreamer_demo_app/MyApplication.kt b/app/src/main/java/com/ray650128/gstreamer_demo_app/MyApplication.kt
new file mode 100644
index 0000000..e151eb6
--- /dev/null
+++ b/app/src/main/java/com/ray650128/gstreamer_demo_app/MyApplication.kt
@@ -0,0 +1,48 @@
+package com.ray650128.gstreamer_demo_app
+
+import android.app.Activity
+import android.app.Application
+import android.content.Context
+import android.os.Bundle
+import android.util.Log
+import kotlin.system.exitProcess
+
+class MyApplication : Application(), Application.ActivityLifecycleCallbacks {
+
+    override fun onCreate() {
+        super.onCreate()
+        instance = this
+    }
+
+    private var currentActivity: Activity? = null
+
+    override fun onActivityCreated(p0: Activity, p1: Bundle?) {}
+
+    override fun onActivityStarted(p0: Activity) {}
+
+    override fun onActivityResumed(p0: Activity) {
+        currentActivity = p0
+    }
+
+    override fun onActivityPaused(p0: Activity) {}
+
+    override fun onActivityStopped(p0: Activity) {}
+
+    override fun onActivitySaveInstanceState(p0: Activity, p1: Bundle) {}
+
+    override fun onActivityDestroyed(p0: Activity) {
+        if (currentActivity?.equals(p0) == true) {
+            Log.e("APP", "EXIT...")
+            onTerminate()
+            exitProcess(0)
+        }
+    }
+
+    companion object {
+        var instance: Application? = null
+
+        fun getAppContext(): Context {
+            return instance!!.applicationContext
+        }
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/ray650128/gstreamer_demo_app/PreferenceUtil.kt b/app/src/main/java/com/ray650128/gstreamer_demo_app/PreferenceUtil.kt
new file mode 100644
index 0000000..b57d581
--- /dev/null
+++ b/app/src/main/java/com/ray650128/gstreamer_demo_app/PreferenceUtil.kt
@@ -0,0 +1,24 @@
+package com.ray650128.gstreamer_demo_app
+
+import android.content.Context
+import com.ray650128.gstreamer_demo_app.ui.mainScreen.MainViewModel
+
+/**
+ * Shared Preferences 工具類別
+ * @author Raymond Yang
+ */
+object PreferenceUtil {
+    private const val MAIN_KEY = "GST_DEMO_APP"
+    private const val IS_FIRST_OPEN_KEY = "IS_FIRST_OPEN_KEY"
+    private const val LAST_SPLIT_MODE = "LAST_SPLIT_MODE"
+
+    private val sharedPreferences = MyApplication.getAppContext().getSharedPreferences(MAIN_KEY, Context.MODE_PRIVATE)
+
+    var isFirstOpen: Boolean
+        get() = sharedPreferences.getBoolean(IS_FIRST_OPEN_KEY, true)
+        set(value) = sharedPreferences.edit().putBoolean(IS_FIRST_OPEN_KEY, value).apply()
+
+    var lastSplitMode: Int
+        get() = sharedPreferences.getInt(LAST_SPLIT_MODE, MainViewModel.PAGE_MODE_ONE)
+        set(value) = sharedPreferences.edit().putInt(LAST_SPLIT_MODE, value).apply()
+}
\ 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 dce6756..d5c7128 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
@@ -57,14 +57,9 @@ class MainActivity : AppCompatActivity() {
             registerOnPageChangeCallback(object: ViewPager2.OnPageChangeCallback() {
                 override fun onPageSelected(position: Int) {
                     super.onPageSelected(position)
-                    /*splitVideoViewAdapter.stop(currentPage)*/
                     currentPage = position
                     splitViewModel.activePage.postValue(position)
                     Log.d("Split", "currentPage: $currentPage")
-                    /*for (i in 0 until splitVideoViewAdapter.itemCount) {
-                        if (i == currentPage) continue
-                        splitVideoViewAdapter.stop(i)
-                    }*/
                 }
             })
         }
diff --git a/app/src/main/java/com/ray650128/gstreamer_demo_app/ui/mainScreen/MainViewModel.kt b/app/src/main/java/com/ray650128/gstreamer_demo_app/ui/mainScreen/MainViewModel.kt
index e73a7e4..afe07c6 100644
--- a/app/src/main/java/com/ray650128/gstreamer_demo_app/ui/mainScreen/MainViewModel.kt
+++ b/app/src/main/java/com/ray650128/gstreamer_demo_app/ui/mainScreen/MainViewModel.kt
@@ -3,6 +3,7 @@ package com.ray650128.gstreamer_demo_app.ui.mainScreen
 import androidx.lifecycle.MediatorLiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
+import com.ray650128.gstreamer_demo_app.PreferenceUtil
 import com.ray650128.gstreamer_demo_app.model.Device
 
 class MainViewModel: ViewModel() {
@@ -17,7 +18,6 @@ class MainViewModel: ViewModel() {
                 password = "hs22601576",
                 stream1 = "/media/video1",
                 stream2 = "/media/video2",
-                //rtspUrl = "rtsp://admin:hs22601576@@192.168.0.73:554/media/video2"
             ),
             Device(
                 deviceName = "192.168.0.77",
@@ -27,7 +27,6 @@ class MainViewModel: ViewModel() {
                 password = "admin",
                 stream1 = "/media/video1",
                 stream2 = "/media/video2",
-                //rtspUrl = "rtsp://admin:admin@192.168.0.77:554/media/video2"
             ),
             Device(
                 deviceName = "192.168.0.79",
@@ -37,7 +36,6 @@ class MainViewModel: ViewModel() {
                 password = "1q2w3e4r!",
                 stream1 = "/media/video1",
                 stream2 = "/media/video2",
-                //rtspUrl = "rtsp://admin:1q2w3e4r!@192.168.0.79:554/media/video2"
             ),
             Device(
                 deviceName = "192.168.0.88",
@@ -47,7 +45,6 @@ class MainViewModel: ViewModel() {
                 password = "1q2w3e4r~",
                 stream1 = "/media/video1",
                 stream2 = "/media/video2",
-                //rtspUrl = "rtsp://admin:1q2w3e4r~@211.23.78.226:8588/media/video2"
             ),
             Device(
                 deviceName = "192.168.0.74",
@@ -57,7 +54,6 @@ class MainViewModel: ViewModel() {
                 password = "admin",
                 stream1 = "/v01",
                 stream2 = "/v02",
-                //rtspUrl = "rtsp://admin:admin@211.23.78.226:8574/v02"
             ),
             Device(
                 deviceName = "192.168.0.75",
@@ -67,7 +63,6 @@ class MainViewModel: ViewModel() {
                 password = "admin",
                 stream1 = "/v01",
                 stream2 = "/v02",
-                //rtspUrl = "rtsp://admin:admin@211.23.78.226:8575/v02"
             ),
             Device(
                 deviceName = "192.168.0.76",
@@ -77,7 +72,6 @@ class MainViewModel: ViewModel() {
                 password = "123456",
                 stream1 = "/profile1",
                 stream2 = "/profile2",
-                //rtspUrl = "rtsp://admin:123456@211.23.78.226:8576/profile2"
             ),
             Device(
                 deviceName = "192.168.0.82",
@@ -87,7 +81,6 @@ class MainViewModel: ViewModel() {
                 password = "123456",
                 stream1 = "/profile1",
                 stream2 = "/profile2",
-                //rtspUrl = "rtsp://admin:123456@192.168.0.82:554/profile2"
             ),
             Device(
                 deviceName = "192.168.0.84",
@@ -97,7 +90,6 @@ class MainViewModel: ViewModel() {
                 password = "123456",
                 stream1 = "/profile1",
                 stream2 = "/profile2",
-                //rtspUrl = "rtsp://admin:123456@192.168.0.84:554/profile2"
             ),
             Device(
                 deviceName = "192.168.0.95",
@@ -107,13 +99,10 @@ class MainViewModel: ViewModel() {
                 password = "123456",
                 stream1 = "/profile1",
                 stream2 = "/profile2",
-                //rtspUrl = "rtsp://admin:123456@192.168.0.95:554/profile2"
             )
         )
     }
 
-    private var splitModeInt: Int = PAGE_MODE_ONE
-
     val splitMode: MutableLiveData<Int> by lazy { MutableLiveData<Int>() }
 
     val cameraList: MediatorLiveData<List<List<Device>>> by lazy {
@@ -125,21 +114,21 @@ class MainViewModel: ViewModel() {
     }
 
     init {
-        setSplitMode(PAGE_MODE_ONE)
+        splitMode.postValue(PreferenceUtil.lastSplitMode)
     }
 
     fun setSplitMode(mode: Int) {
-        splitModeInt = mode
-        splitMode.postValue(splitModeInt)
+        PreferenceUtil.lastSplitMode = mode
+        splitMode.postValue(PreferenceUtil.lastSplitMode)
     }
 
     private fun updateCameraList(dbData: List<Device>?): List<List<Device>>? {
         if (dbData.isNullOrEmpty()) return null
         val tmpData = ArrayList<List<Device>>()
-        for (index in uriList.indices step (splitModeInt)) {
+        for (index in uriList.indices step (PreferenceUtil.lastSplitMode)) {
             if (index == uriList.size) break
             val tmpSubData = ArrayList<Device>()
-            for (subIndex in 0 until (splitModeInt)) {
+            for (subIndex in 0 until (PreferenceUtil.lastSplitMode)) {
                 val dataIndex = index + subIndex
                 if (dataIndex !in uriList.indices) break
                 tmpSubData.add(uriList[dataIndex])