diff --git a/app/src/main/java/com/github/catvod/spider/Init.java b/app/src/main/java/com/github/catvod/spider/Init.java
index d61d128..fc8c1ad 100644
--- a/app/src/main/java/com/github/catvod/spider/Init.java
+++ b/app/src/main/java/com/github/catvod/spider/Init.java
@@ -1,19 +1,17 @@
 package com.github.catvod.spider;
 
-import android.Manifest;
 import android.app.Activity;
 import android.app.Application;
 import android.content.Context;
-import android.content.pm.PackageManager;
-import android.os.Build;
+import android.os.Bundle;
 import android.os.Handler;
 import android.os.Looper;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
 import com.github.catvod.crawler.SpiderDebug;
-import com.github.catvod.utils.Notify;
 
-import java.lang.reflect.Field;
-import java.util.Map;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
@@ -21,6 +19,7 @@ public class Init {
 
     private final ExecutorService executor;
     private final Handler handler;
+    private Activity activity;
     private Application app;
 
     private static class Loader {
@@ -40,9 +39,18 @@ public class Init {
         return get().app;
     }
 
+    public static Activity activity() {
+        return get().activity;
+    }
+
+    private void setActivity(Activity activity) {
+        this.activity = activity;
+    }
+
     public static void init(Context context) {
         get().app = ((Application) context);
         SpiderDebug.log("自定義爬蟲代碼載入成功！");
+        registerActivityLifecycleCallbacks();
         Proxy.init();
     }
 
@@ -58,32 +66,41 @@ public class Init {
         get().handler.postDelayed(runnable, delay);
     }
 
-    public static void checkPermission() {
-        try {
-            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) return;
-            if (context().checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) return;
-            Notify.show("請允許儲存權限");
-        } catch (Exception e) {
-            e.printStackTrace();
-        }
-    }
+    private static void registerActivityLifecycleCallbacks() {
+        get().app.registerActivityLifecycleCallbacks(new Application.ActivityLifecycleCallbacks() {
+            @Override
+            public void onActivityCreated(@NonNull Activity activity, @Nullable Bundle savedInstanceState) {
+                if (activity != activity()) get().setActivity(activity);
+            }
+
+            @Override
+            public void onActivityStarted(@NonNull Activity activity) {
+                if (activity != activity()) get().setActivity(activity);
+            }
+
+            @Override
+            public void onActivityResumed(@NonNull Activity activity) {
+                if (activity != activity()) get().setActivity(activity);
+            }
+
+            @Override
+            public void onActivityPaused(@NonNull Activity activity) {
+                if (activity == activity()) get().setActivity(null);
+            }
+
+            @Override
+            public void onActivityStopped(@NonNull Activity activity) {
+                if (activity == activity()) get().setActivity(null);
+            }
+
+            @Override
+            public void onActivityDestroyed(@NonNull Activity activity) {
+                if (activity == activity()) get().setActivity(null);
+            }
 
-    public static Activity getActivity() throws Exception {
-        Class<?> activityThreadClass = Class.forName("android.app.ActivityThread");
-        Object activityThread = activityThreadClass.getMethod("currentActivityThread").invoke(null);
-        Field activitiesField = activityThreadClass.getDeclaredField("mActivities");
-        activitiesField.setAccessible(true);
-        Map<?, ?> activities = (Map<?, ?>) activitiesField.get(activityThread);
-        for (Object o : activities.values()) {
-            Class<?> clz = o.getClass();
-            Field pausedField = clz.getDeclaredField("paused");
-            pausedField.setAccessible(true);
-            if (!pausedField.getBoolean(o)) {
-                Field activityField = clz.getDeclaredField("activity");
-                activityField.setAccessible(true);
-                return (Activity) activityField.get(o);
+            @Override
+            public void onActivitySaveInstanceState(@NonNull Activity activity, @NonNull Bundle outState) {
             }
-        }
-        return null;
+        });
     }
 }
diff --git a/app/src/main/java/com/github/catvod/spider/Market.java b/app/src/main/java/com/github/catvod/spider/Market.java
index e3d7b94..60d25d0 100644
--- a/app/src/main/java/com/github/catvod/spider/Market.java
+++ b/app/src/main/java/com/github/catvod/spider/Market.java
@@ -42,7 +42,6 @@ public class Market extends Spider {
     public void init(Context context, String extend) throws Exception {
         if (extend.startsWith("http")) extend = OkHttp.string(extend);
         datas = Data.arrayFrom(extend);
-        Init.checkPermission();
     }
 
     @Override
@@ -81,8 +80,7 @@ public class Market extends Spider {
     }
 
     private void download(File file, InputStream is, double length) throws Exception {
-        FileOutputStream os = new FileOutputStream(file);
-        try (BufferedInputStream input = new BufferedInputStream(is)) {
+        try (BufferedInputStream input = new BufferedInputStream(is); FileOutputStream os = new FileOutputStream(file)) {
             byte[] buffer = new byte[4096];
             int readBytes;
             long totalBytes = 0;
@@ -107,7 +105,7 @@ public class Market extends Spider {
     private void setDialog() {
         Init.run(() -> {
             try {
-                dialog = new ProgressDialog(Init.getActivity());
+                dialog = new ProgressDialog(Init.activity());
                 dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
                 dialog.setCancelable(false);
                 if (isBusy()) dialog.show();
diff --git a/jar/custom_spider.jar b/jar/custom_spider.jar
index 65da7ef..21e5b75 100644
Binary files a/jar/custom_spider.jar and b/jar/custom_spider.jar differ
diff --git a/jar/custom_spider.jar.md5 b/jar/custom_spider.jar.md5
index 9e1466f..bd4f81c 100644
--- a/jar/custom_spider.jar.md5
+++ b/jar/custom_spider.jar.md5
@@ -1 +1 @@
-62ec6f78832485cdccc43870fed1b860
+68e7568f6083fda151a310919aab9acf