Fix #478

src/main/scala/com/github/shadowsocks/AppManager.scala

@@ -150,6 +150,10 @@ class AppManager extends AppCompatActivity with OnCheckedChangeListener with OnC
       handler.removeCallbacksAndMessages(null)
       handler = null
     }
+    if (overlay != null) {
+      getWindowManager.removeViewImmediate(overlay)
+      overlay = null
+    }
   }
 
   def onMenuItemClick(item: MenuItem): Boolean = {
@@ -210,7 +214,7 @@ class AppManager extends AppCompatActivity with OnCheckedChangeListener with OnC
     toolbar.inflateMenu(R.menu.app_manager_menu)
     toolbar.setOnMenuItemClickListener(this)
 
-    this.overlay = View.inflate(this, R.layout.overlay, null).asInstanceOf[TextView]
+    overlay = View.inflate(this, R.layout.overlay, null).asInstanceOf[TextView]
     getWindowManager.addView(overlay, new
         WindowManager.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT,
           WindowManager.LayoutParams.TYPE_APPLICATION,
@@ -219,7 +223,7 @@ class AppManager extends AppCompatActivity with OnCheckedChangeListener with OnC
 
     findViewById(R.id.onSwitch).asInstanceOf[Switch]
       .setOnCheckedChangeListener((button: CompoundButton, checked: Boolean) => {
-        ShadowsocksApplication.settings.edit().putBoolean(Key.isProxyApps, checked).apply()
+        ShadowsocksApplication.settings.edit().putBoolean(Key.isProxyApps, checked).commit()
         finish()
       })
 

src/main/scala/com/github/shadowsocks/ShadowsocksSettings.scala

@@ -24,10 +24,6 @@ class ShadowsocksSettings extends PreferenceFragment with OnSharedPreferenceChan
     getPreferenceManager.getSharedPreferences.registerOnSharedPreferenceChangeListener(this)
 
     isProxyApps = findPreference(Key.isProxyApps).asInstanceOf[SwitchPreference]
-    isProxyApps.setOnPreferenceChangeListener((preference: Preference, newValue: Any) => {
-      startActivity(new Intent(activity, classOf[AppManager]))
-      newValue.asInstanceOf[Boolean]  // keep it ON
-    })
 
     findPreference("recovery").setOnPreferenceClickListener((preference: Preference) => {
       ShadowsocksApplication.track(Shadowsocks.TAG, "reset")
@@ -67,8 +63,19 @@ class ShadowsocksSettings extends PreferenceFragment with OnSharedPreferenceChan
   }
 
   override def onResume {
-    super.onResume
+    super.onResume()
     isProxyApps.setChecked(ShadowsocksApplication.settings.getBoolean(Key.isProxyApps, false))  // update
+    isProxyApps.setOnPreferenceChangeListener((preference: Preference, newValue: Any) => {
+      if (newValue.asInstanceOf[Boolean] == true) {
+        startActivity(new Intent(activity, classOf[AppManager]))
+      }
+      true
+    })
+  }
+
+  override def onPause {
+    super.onPause()
+    isProxyApps.setOnPreferenceChangeListener(null)
   }
 
   def onSharedPreferenceChanged(sharedPreferences: SharedPreferences, key: String) = key match {