diff --git a/.idea/google-java-format.xml b/.idea/google-java-format.xml
new file mode 100644
index 0000000..2aa056d
--- /dev/null
+++ b/.idea/google-java-format.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="GoogleJavaFormatSettings">
+    <option name="enabled" value="false" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/inspectionProfiles/Project_Default.xml b/.idea/inspectionProfiles/Project_Default.xml
new file mode 100644
index 0000000..cf247ce
--- /dev/null
+++ b/.idea/inspectionProfiles/Project_Default.xml
@@ -0,0 +1,6 @@
+<component name="InspectionProjectProfileManager">
+  <profile version="1.0">
+    <option name="myName" value="Project Default" />
+    <inspection_tool class="UsePropertyAccessSyntax" enabled="true" level="WEAK WARNING" enabled_by_default="true" />
+  </profile>
+</component>
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
index cb150cf..8562ed5 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -1,4 +1,3 @@
-<?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="ExternalStorageConfigurationManager" enabled="true" />
   <component name="ProjectRootManager" version="2" languageLevel="JDK_21" default="true" project-jdk-name="21" project-jdk-type="JavaSDK">
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
new file mode 100644
index 0000000..94a25f7
--- /dev/null
+++ b/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/app/lint-baseline.xml b/app/lint-baseline.xml
new file mode 100644
index 0000000..56f5523
--- /dev/null
+++ b/app/lint-baseline.xml
@@ -0,0 +1,179 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<issues format="6" by="lint 8.10.0" type="baseline" client="gradle" dependencies="false" name="AGP (8.10.0)" variant="all" version="8.10.0">
+
+    <issue
+        id="ScopedStorage"
+        message="The Google Play store has a policy that limits usage of MANAGE_EXTERNAL_STORAGE"
+        errorLine1="&lt;uses-permission android:name=&quot;android.permission.MANAGE_EXTERNAL_STORAGE&quot; />"
+        errorLine2="                               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~">
+        <location
+            file="src/main/AndroidManifest.xml"
+            line="10"
+            column="32"/>
+    </issue>
+
+    <issue
+        id="OldTargetApi"
+        message="Not targeting the latest versions of Android; compatibility modes apply. Consider testing and updating this version. Consult the `android.os.Build.VERSION_CODES` javadoc for details."
+        errorLine1="        targetSdk 35"
+        errorLine2="        ~~~~~~~~~~~~">
+        <location
+            file="build.gradle"
+            line="12"
+            column="9"/>
+    </issue>
+
+    <issue
+        id="HighSamplingRate"
+        message="Most apps don&apos;t need access to high sensor sampling rate."
+        errorLine1="    &lt;uses-permission android:name=&quot;android.permission.HIGH_SAMPLING_RATE_SENSORS&quot; />"
+        errorLine2="                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~">
+        <location
+            file="src/main/AndroidManifest.xml"
+            line="15"
+            column="36"/>
+    </issue>
+
+    <issue
+        id="ProtectedPermissions"
+        message="Permission is only granted to system apps"
+        errorLine1="&lt;uses-permission android:name=&quot;android.permission.BIND_VPN_SERVICE&quot; />"
+        errorLine2="                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~">
+        <location
+            file="src/main/AndroidManifest.xml"
+            line="11"
+            column="18"/>
+    </issue>
+
+    <issue
+        id="ObsoleteLayoutParam"
+        message="Invalid layout param in a `LinearLayout`: `layout_centerInParent`"
+        errorLine1="        android:layout_centerInParent=&quot;true&quot;/>"
+        errorLine2="        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~">
+        <location
+            file="src/main/res/layout/activity_main.xml"
+            line="20"
+            column="9"/>
+    </issue>
+
+    <issue
+        id="Overdraw"
+        message="Possible overdraw: Root element paints background `@drawable/background` with a theme that also paints a background (inferred theme is `@style/Theme.StudyApp`)"
+        errorLine1="    android:background=&quot;@drawable/background&quot;>"
+        errorLine2="    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~">
+        <location
+            file="src/main/res/layout/activity_main.xml"
+            line="12"
+            column="5"/>
+    </issue>
+
+    <issue
+        id="UnusedResources"
+        message="The resource `R.color.black` appears to be unused"
+        errorLine1="    &lt;color name=&quot;black&quot;>#FF000000&lt;/color>"
+        errorLine2="           ~~~~~~~~~~~~">
+        <location
+            file="src/main/res/values/colors.xml"
+            line="3"
+            column="12"/>
+    </issue>
+
+    <issue
+        id="UnusedResources"
+        message="The resource `R.color.white` appears to be unused"
+        errorLine1="    &lt;color name=&quot;white&quot;>#FFFFFFFF&lt;/color>"
+        errorLine2="           ~~~~~~~~~~~~">
+        <location
+            file="src/main/res/values/colors.xml"
+            line="4"
+            column="12"/>
+    </issue>
+
+    <issue
+        id="UnusedResources"
+        message="The resource `R.mipmap.ic_launcher` appears to be unused">
+        <location
+            file="src/main/res/mipmap-hdpi/ic_launcher.webp"/>
+    </issue>
+
+    <issue
+        id="UnusedResources"
+        message="The resource `R.string.app_name` appears to be unused"
+        errorLine1="    &lt;string name=&quot;app_name&quot;>study.App&lt;/string>"
+        errorLine2="            ~~~~~~~~~~~~~~~">
+        <location
+            file="src/main/res/values/strings.xml"
+            line="2"
+            column="13"/>
+    </issue>
+
+    <issue
+        id="IconLauncherShape"
+        message="Launcher icons should not fill every pixel of their square region; see the design guide for details">
+        <location
+            file="src/main/res/mipmap-hdpi/box.png"/>
+    </issue>
+
+    <issue
+        id="IconLocation"
+        message="Found bitmap drawable `res/drawable/background.jpg` in densityless folder">
+        <location
+            file="src/main/res/drawable/background.jpg"/>
+    </issue>
+
+    <issue
+        id="UseTomlInstead"
+        message="Use version catalog instead"
+        errorLine1="    implementation &apos;com.squareup.retrofit2:retrofit:2.9.0&apos;"
+        errorLine2="                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~">
+        <location
+            file="build.gradle"
+            line="41"
+            column="20"/>
+    </issue>
+
+    <issue
+        id="UseTomlInstead"
+        message="Use version catalog instead"
+        errorLine1="    implementation &apos;com.squareup.retrofit2:converter-gson:2.9.0&apos;"
+        errorLine2="                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~">
+        <location
+            file="build.gradle"
+            line="44"
+            column="20"/>
+    </issue>
+
+    <issue
+        id="UseTomlInstead"
+        message="Use version catalog instead"
+        errorLine1="    implementation &apos;com.squareup.retrofit2:adapter-rxjava3:2.9.0&apos;"
+        errorLine2="                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~">
+        <location
+            file="build.gradle"
+            line="47"
+            column="20"/>
+    </issue>
+
+    <issue
+        id="HardcodedText"
+        message="Hardcoded string &quot;点击开始运行&quot;, should use `@string` resource"
+        errorLine1="        android:text=&quot;点击开始运行&quot;"
+        errorLine2="        ~~~~~~~~~~~~~~~~~~~~~">
+        <location
+            file="src/main/res/layout/activity_main.xml"
+            line="18"
+            column="9"/>
+    </issue>
+
+    <issue
+        id="HardcodedText"
+        message="Hardcoded string &quot;运行脚本按钮&quot;, should use `@string` resource"
+        errorLine1="        android:contentDescription=&quot;运行脚本按钮&quot;"
+        errorLine2="        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~">
+        <location
+            file="src/main/res/layout/activity_main.xml"
+            line="19"
+            column="9"/>
+    </issue>
+
+</issues>
diff --git a/app/src/main/java/com/example/studyapp/MainActivity.java b/app/src/main/java/com/example/studyapp/MainActivity.java
index 5779511..32e5a2e 100644
--- a/app/src/main/java/com/example/studyapp/MainActivity.java
+++ b/app/src/main/java/com/example/studyapp/MainActivity.java
@@ -247,12 +247,6 @@ public class MainActivity extends AppCompatActivity {
 
             intent = new Intent(this, CustomVpnService.class);
 
-            if (intent == null) {
-                Log.e("handleVpnPermissionResult", "Intent is null. Cannot start service.");
-                showToastOnUiThread(this, "Failed to start VPN service due to null intent.");
-                return;
-            }
-
             try {
                 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                     startForegroundService(intent);