diff --git a/app/src/main/java/com/example/flightgearcontrollerapp/views/MainActivity.kt b/app/src/main/java/com/example/flightgearcontrollerapp/views/MainActivity.kt
index 20637d6..7dfae72 100644
--- a/app/src/main/java/com/example/flightgearcontrollerapp/views/MainActivity.kt
+++ b/app/src/main/java/com/example/flightgearcontrollerapp/views/MainActivity.kt
@@ -4,6 +4,7 @@ import android.os.Bundle
 import android.view.View
 import android.widget.Button
 import android.widget.EditText
+import android.widget.Toast
 import androidx.appcompat.app.AlertDialog
 import androidx.appcompat.app.AppCompatActivity
 import com.example.flightgearcontrollerapp.R
@@ -27,11 +28,19 @@ class MainActivity : AppCompatActivity() {
             if (!isConnected) {
                 val editTextIP = findViewById<EditText>(ip_address)
                 val editTextPort = findViewById<EditText>(port_address)
+                if (editTextIP.text.toString() ==""){
+                    Toast.makeText(applicationContext, "Please write IP address", Toast.LENGTH_SHORT).show()
+                    return
+                }
+                if (editTextPort.text.toString()==""){
+                    Toast.makeText(applicationContext, "Please write port address", Toast.LENGTH_SHORT).show()
+                    return
+                }
                 val builder = AlertDialog.Builder(this)
                 builder.setTitle(getString(R.string.alert_dialog_flightgear_connection))
                 builder.setMessage(getString(R.string.alert_instruction))
                 builder.setPositiveButton(getString(R.string.ok_btn)){ dialog, _ ->
-                    if ((editTextIP.text.toString() !="")&&(editTextPort.text.toString()!="")&&(vmConnection.connectToFG(editTextIP.text.toString(),editTextPort.text.toString()))) {
+                    if (vmConnection.connectToFG(editTextIP.text.toString(),editTextPort.text.toString())) {
                         btnConnection.setText(R.string.disconnect)
                         isConnected = true
                     } else {
diff --git a/app/src/main/res/layout/activity_main.xml b/app/src/main/res/layout/activity_main.xml
index 38f941a..732861e 100644
--- a/app/src/main/res/layout/activity_main.xml
+++ b/app/src/main/res/layout/activity_main.xml
@@ -138,13 +138,13 @@
 
                     <com.jackandphantom.joystickview.JoyStickView
                         android:id="@+id/widget_joystick"
-                        android:layout_width="360sp"
-                        android:layout_height="360sp"
+                        android:layout_width="match_parent"
+                        android:layout_height="match_parent"
 
                         android:layout_alignParentEnd="true"
                         android:layout_alignParentBottom="true"
                         android:layout_marginEnd="0dp"
-                        android:layout_marginBottom="-3dp"
+                        android:layout_marginBottom="0dp"
                         app:innerCircleColor="#f6FFFFFF"
                         app:innerCircleImage="@drawable/ic_baseline_airplanemode_active_24"
                         app:outerCircleBorderColor="#fff"
@@ -155,6 +155,7 @@
                 </RelativeLayout>
 
                 <GridLayout
+
                     android:layout_width="100sp"
                     android:layout_height="match_parent"
                     android:background="@color/white_40">
@@ -210,10 +211,13 @@
                     android:textStyle="bold" />
 
                 <com.google.android.material.slider.Slider
-                    android:layout_width="390sp"
+                    android:layout_width="match_parent"
                     android:layout_marginLeft="30sp"
+                    android:layout_marginRight="30sp"
                     android:layout_height="0sp"
                     android:layout_weight="0"
+                    app:trackColorActive="@color/navy_blue_40"
+                    app:trackColorInactive="@color/navy_blue_40"
                     android:value="0"
                     android:valueFrom="-1"
                     android:valueTo="1" />
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index fbdcc5d..b143b1c 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -8,7 +8,7 @@
     <string name="txt_rudder">Rudder</string>
     <string name="disconnect">disconnect</string>
     <string name="alert_dialog_flightgear_connection">FlightGear Connection</string>
-    <string name="alert_instruction">For connecting to FlightGear App,\nFirst open the app.\nThen, copy these lines to Setting-> Additional Setting:\n\n &#45;&#45;generic=socket,in,10,\'ip\',\'port\',tcp,playback_small \n &#45;&#45;fdm=null\n\n and now just press fly!</string>
+    <string name="alert_instruction">For connecting to FlightGear App,\nFirst open the app.\nThen, copy these lines to Setting-> Additional Setting:\n\n &#45;&#45;telnet=socket,in,10,\'ip\',\'port\',tcp,playback_small \n\n and now just press fly!</string>
     <string name="ok_btn">continue</string>
     <string name="alert_title">FlightGear Connection</string>
     <string name="connection_failed">Connection failed!</string>