🚸 Improve settings structure

app/src/main/java/ch/dissem/apps/abit/SettingsFragment.kt

@@ -21,10 +21,14 @@ import android.content.*
 import android.os.Bundle
 import android.os.IBinder
 import android.preference.PreferenceManager
+import android.support.v4.app.Fragment
+import android.support.v4.content.ContextCompat
 import android.support.v4.content.FileProvider.getUriForFile
 import android.support.v7.preference.Preference
 import android.support.v7.preference.PreferenceFragmentCompat
+import android.support.v7.preference.PreferenceScreen
 import android.support.v7.preference.SwitchPreferenceCompat
+import android.view.View
 import android.widget.Toast
 import ch.dissem.apps.abit.service.BatchProcessorService
 import ch.dissem.apps.abit.service.SimpleJob
@@ -46,23 +50,24 @@ import java.util.*
 /**
  * @author Christian Basler
  */
-class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedPreferenceChangeListener {
+class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedPreferenceChangeListener,
+    PreferenceFragmentCompat.OnPreferenceStartScreenCallback {
 
     override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
-        addPreferencesFromResource(R.xml.preferences)
+        setPreferencesFromResource(R.xml.preferences, rootKey)
 
         findPreference("about")?.onPreferenceClickListener = aboutClickListener()
-        val cleanup = findPreference("cleanup")
+        findPreference("cleanup")?.let { it.onPreferenceClickListener = cleanupClickListener(it) }
-        cleanup?.onPreferenceClickListener = cleanupClickListener(cleanup)
         findPreference("export")?.onPreferenceClickListener = exportClickListener()
         findPreference("import")?.onPreferenceClickListener = importClickListener()
-        findPreference("status").onPreferenceClickListener = statusClickListener()
+        findPreference("status")?.onPreferenceClickListener = statusClickListener()
-        val conversationInit = findPreference("emulate_conversations_initialize") as? SwitchPreferenceCompat
+
+        val emulateConversations = findPreference("emulate_conversations") as? SwitchPreferenceCompat
+        val conversationInit = findPreference("emulate_conversations_initialize")
+
+        emulateConversations?.onPreferenceChangeListener = emulateConversationChangeListener(conversationInit)
         conversationInit?.onPreferenceClickListener = conversationInitClickListener()
-        findPreference("emulate_conversations")?.apply {
+        conversationInit?.isEnabled = emulateConversations?.isChecked ?: false
-            onPreferenceChangeListener = emulateConversationChangeListener(conversationInit)
-            isEnabled = conversationInit?.isChecked ?: false
-        }
     }
 
     private fun aboutClickListener() = Preference.OnPreferenceClickListener {
@@ -210,7 +215,8 @@ class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedP
                 val messageRepo = Singleton.getMessageRepository(service.service)
                 val conversationService = Singleton.getConversationService(service.service)
 
-                service.process(SimpleJob<Plaintext>(
+                service.process(
+                    SimpleJob<Plaintext>(
                         messageRepo.count(),
                         { messageRepo.findNextLegacyMessages(it) },
                         { msg ->
@@ -224,7 +230,8 @@ class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedP
                         },
                         R.drawable.ic_notification_batch,
                         R.string.emulate_conversations_batch
-                ))
+                    )
+                )
             }
         }
 
@@ -239,11 +246,39 @@ class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedP
         true
     }
 
-    private fun emulateConversationChangeListener(conversationInit: Preference?) = Preference.OnPreferenceChangeListener { _, newValue ->
+    private fun emulateConversationChangeListener(conversationInit: Preference?) =
+        Preference.OnPreferenceChangeListener { _, newValue ->
             conversationInit?.isEnabled = newValue as Boolean
             true
         }
 
+    // The why-is-it-so-damn-hard-to-group-preferences section
+    override fun getCallbackFragment(): Fragment = this
+
+    override fun onPreferenceStartScreen(
+        preferenceFragmentCompat: PreferenceFragmentCompat,
+        preferenceScreen: PreferenceScreen
+    ): Boolean {
+        fragmentManager?.beginTransaction()?.let { ft ->
+            val fragment = SettingsFragment()
+            fragment.arguments = Bundle().apply {
+                putString(PreferenceFragmentCompat.ARG_PREFERENCE_ROOT, preferenceScreen.key)
+            }
+            ft.add(R.id.item_list, fragment, preferenceScreen.key)
+            ft.addToBackStack(preferenceScreen.key)
+            ft.commit()
+        }
+        return true
+    }
+
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        super.onViewCreated(view, savedInstanceState)
+        context?.let { ctx -> view.setBackgroundColor(ContextCompat.getColor(ctx, R.color.contentBackground)) }
+    }
+    // End of the why-is-it-so-damn-hard-to-group-preferences section
+    // Afterthought: here it looks so simple: https://developer.android.com/guide/topics/ui/settings.html
+    // Remind me, why do we need to use PreferenceFragmentCompat?
+
     companion object {
         const val WRITE_EXPORT_REQUEST_CODE = 1
         const val READ_IMPORT_REQUEST_CODE = 2

app/src/main/res/values/strings.xml

@@ -141,4 +141,12 @@ As an alternative you could configure a trusted node in the settings, but as of
     <string name="emulate_conversations_summary">Use subject to determine which messages belong together. The order will likely be wrong.</string>
     <string name="emulate_conversations_initialize">Group existing messages by subject</string>
     <string name="emulate_conversations_batch">Grouping existing messages by subject</string>
+    <string name="preference_group_user_experience">Behaviour</string>
+    <string name="preference_group_user_experience_summary">Change how messages are displayed</string>
+    <string name="preference_group_network_and_performance">Network &amp; Performance</string>
+    <string name="preference_group_network_and_performance_summary">Tweak network usage and protocol details</string>
+    <string name="preference_group_advanced">Advanced</string>
+    <string name="preference_group_advanced_summary"></string>
+    <string name="preference_group_experimental">Experimental</string>
+    <string name="preference_group_experimental_summary">Only change if you know what you\'re doing</string>
 </resources>

app/src/main/res/xml/preferences.xml

@@ -1,10 +1,12 @@
 <?xml version="1.0" encoding="utf-8"?>
 <android.support.v7.preference.PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
-    <android.support.v7.preference.SwitchPreferenceCompat
+
-        android:defaultValue="true"
+    <android.support.v7.preference.PreferenceScreen
-        android:key="wifi_only"
+        android:key="preference_ux"
-        android:summary="@string/wifi_only_summary"
+        android:title="@string/preference_group_user_experience"
-        android:title="@string/wifi_only" />
+        android:summary="@string/preference_group_user_experience_summary"
+        android:persistent="false">
+
         <android.support.v7.preference.SwitchPreferenceCompat
             android:defaultValue="true"
             android:key="emulate_conversations"
@@ -15,11 +17,53 @@
             android:key="emulate_conversations_initialize"
             android:summary="@string/emulate_conversations_summary"
             android:title="@string/emulate_conversations_initialize" />
+
+    </android.support.v7.preference.PreferenceScreen>
+
+    <android.support.v7.preference.PreferenceScreen
+        android:key="preference_network_and_performance"
+        android:title="@string/preference_group_network_and_performance"
+        android:summary="@string/preference_group_network_and_performance_summary"
+        android:persistent="false">
+
+        <android.support.v7.preference.SwitchPreferenceCompat
+            android:defaultValue="true"
+            android:key="wifi_only"
+            android:summary="@string/wifi_only_summary"
+            android:title="@string/wifi_only" />
         <android.support.v7.preference.SwitchPreferenceCompat
             android:defaultValue="true"
             android:key="request_acknowledgements"
             android:summary="@string/request_acknowledgements_summary"
             android:title="@string/request_acknowledgements" />
+
+    </android.support.v7.preference.PreferenceScreen>
+
+    <android.support.v7.preference.PreferenceScreen
+        android:key="preference_advanced"
+        android:title="@string/preference_group_advanced"
+        android:summary="@string/preference_group_advanced_summary"
+        android:persistent="false">
+
+        <android.support.v7.preference.Preference
+            android:key="cleanup"
+            android:summary="@string/cleanup_summary"
+            android:title="@string/cleanup" />
+        <android.support.v7.preference.Preference
+            android:key="export"
+            android:summary="@string/export_data_summary"
+            android:title="@string/export_data" />
+        <android.support.v7.preference.Preference
+            android:key="import"
+            android:summary="@string/import_data_summary"
+            android:title="@string/import_data" />
+
+        <android.support.v7.preference.PreferenceScreen
+            android:key="preference_experimental"
+            android:title="@string/preference_group_experimental"
+            android:summary="@string/preference_group_experimental_summary"
+            android:persistent="false">
+
             <android.support.v7.preference.EditTextPreference
                 android:inputType="textUri"
                 android:key="trusted_node"
@@ -37,6 +81,15 @@
                 android:key="server_pow"
                 android:summary="@string/server_pow_summary"
                 android:title="@string/server_pow" />
+            <android.support.v7.preference.Preference
+                android:key="status"
+                android:summary="@string/status_summary"
+                android:title="@string/status" />
+
+        </android.support.v7.preference.PreferenceScreen>
+
+    </android.support.v7.preference.PreferenceScreen>
+
     <android.support.v7.preference.Preference
         android:key="about"
         android:summary="@string/about_summary"
@@ -49,20 +102,4 @@
             android:action="android.intent.action.VIEW"
             android:data="@string/help_out_link" />
     </android.support.v7.preference.Preference>
-    <android.support.v7.preference.Preference
-        android:key="cleanup"
-        android:summary="@string/cleanup_summary"
-        android:title="@string/cleanup" />
-    <android.support.v7.preference.Preference
-        android:key="export"
-        android:summary="@string/export_data_summary"
-        android:title="@string/export_data" />
-    <android.support.v7.preference.Preference
-        android:key="import"
-        android:summary="@string/import_data_summary"
-        android:title="@string/import_data" />
-    <android.support.v7.preference.Preference
-        android:key="status"
-        android:summary="@string/status_summary"
-        android:title="@string/status" />
 </android.support.v7.preference.PreferenceScreen>