Handle preference fragments using the framework (#3090)

* Handle preference fragments using the framework

The previous code started new preference "screens" as activities, even though
each one hosted a single fragment.

Modify this to use the framework's support for swapping in/out different
preference fragments.

PreferencesActivity:
- Remove the code for launching tab and proxy preferences
- Remove the code for setting titles, each fragment is responsible for that
- Implement OnPreferenceStartFragmentCallback to swap fragments in/out with
  the correct animation

PreferencesFragment:
- Use `fragment` property instead of `setOnPreferenceClickListener`
- Set the activity title when resuming

Everything else:
- Set the activity title when resuming

* Lint

* Use the commit extension function

app/src/main/java/com/keylesspalace/tusky/components/preference/AccountPreferencesFragment.kt

@@ -324,6 +324,11 @@ class AccountPreferencesFragment : PreferenceFragmentCompat(), Injectable {
         }
     }
 
+    override fun onResume() {
+        super.onResume()
+        requireActivity().setTitle(R.string.action_view_account_preferences)
+    }
+
     private fun openNotificationPrefs() {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
             val intent = Intent()

app/src/main/java/com/keylesspalace/tusky/components/preference/NotificationPreferencesFragment.kt

@@ -204,6 +204,11 @@ class NotificationPreferencesFragment : PreferenceFragmentCompat(), Injectable {
         }
     }
 
+    override fun onResume() {
+        super.onResume()
+        requireActivity().setTitle(R.string.pref_title_edit_notification_settings)
+    }
+
     companion object {
         fun newInstance(): NotificationPreferencesFragment {
             return NotificationPreferencesFragment()

app/src/main/java/com/keylesspalace/tusky/components/preference/PreferencesActivity.kt

@@ -23,6 +23,8 @@ import android.util.Log
 import androidx.activity.OnBackPressedCallback
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.commit
+import androidx.preference.Preference
+import androidx.preference.PreferenceFragmentCompat
 import androidx.preference.PreferenceManager
 import com.keylesspalace.tusky.BaseActivity
 import com.keylesspalace.tusky.MainActivity
@@ -41,6 +43,7 @@ import javax.inject.Inject
 class PreferencesActivity :
     BaseActivity(),
     SharedPreferences.OnSharedPreferenceChangeListener,
+    PreferenceFragmentCompat.OnPreferenceStartFragmentCallback,
     HasAndroidInjector {
 
     @Inject
@@ -82,8 +85,6 @@ class PreferencesActivity :
                 GENERAL_PREFERENCES -> PreferencesFragment.newInstance()
                 ACCOUNT_PREFERENCES -> AccountPreferencesFragment.newInstance()
                 NOTIFICATION_PREFERENCES -> NotificationPreferencesFragment.newInstance()
-                TAB_FILTER_PREFERENCES -> TabFilterPreferencesFragment.newInstance()
-                PROXY_PREFERENCES -> ProxyPreferencesFragment.newInstance()
                 else -> throw IllegalArgumentException("preferenceType not known")
             }
 
@@ -91,18 +92,34 @@ class PreferencesActivity :
             replace(R.id.fragment_container, fragment, fragmentTag)
         }
 
-        when (preferenceType) {
-            GENERAL_PREFERENCES -> setTitle(R.string.action_view_preferences)
-            ACCOUNT_PREFERENCES -> setTitle(R.string.action_view_account_preferences)
-            NOTIFICATION_PREFERENCES -> setTitle(R.string.pref_title_edit_notification_settings)
-            TAB_FILTER_PREFERENCES -> setTitle(R.string.pref_title_post_tabs)
-            PROXY_PREFERENCES -> setTitle(R.string.pref_title_http_proxy_settings)
-        }
-
         onBackPressedDispatcher.addCallback(this, restartActivitiesOnBackPressedCallback)
         restartActivitiesOnBackPressedCallback.isEnabled = savedInstanceState?.getBoolean(EXTRA_RESTART_ON_BACK, false) ?: false
     }
 
+    override fun onPreferenceStartFragment(
+        caller: PreferenceFragmentCompat,
+        pref: Preference
+    ): Boolean {
+        val args = pref.extras
+        val fragment = supportFragmentManager.fragmentFactory.instantiate(
+            classLoader,
+            pref.fragment!!
+        )
+        fragment.arguments = args
+        fragment.setTargetFragment(caller, 0)
+        supportFragmentManager.commit {
+            setCustomAnimations(
+                R.anim.slide_from_right,
+                R.anim.slide_to_left,
+                R.anim.slide_from_left,
+                R.anim.slide_to_right
+            )
+            replace(R.id.fragment_container, fragment)
+            addToBackStack(null)
+        }
+        return true
+    }
+
     override fun onResume() {
         super.onResume()
         PreferenceManager.getDefaultSharedPreferences(this).registerOnSharedPreferenceChangeListener(this)
@@ -159,8 +176,6 @@ class PreferencesActivity :
         const val GENERAL_PREFERENCES = 0
         const val ACCOUNT_PREFERENCES = 1
         const val NOTIFICATION_PREFERENCES = 2
-        const val TAB_FILTER_PREFERENCES = 3
-        const val PROXY_PREFERENCES = 4
         private const val EXTRA_PREFERENCE_TYPE = "EXTRA_PREFERENCE_TYPE"
         private const val EXTRA_RESTART_ON_BACK = "restart"
 

app/src/main/java/com/keylesspalace/tusky/components/preference/PreferencesFragment.kt

@@ -206,14 +206,7 @@ class PreferencesFragment : PreferenceFragmentCompat(), Injectable {
             preferenceCategory(R.string.pref_title_timeline_filters) {
                 preference {
                     setTitle(R.string.pref_title_post_tabs)
-                    setOnPreferenceClickListener {
-                        activity?.let { activity ->
-                            val intent = PreferencesActivity.newIntent(activity, PreferencesActivity.TAB_FILTER_PREFERENCES)
-                            activity.startActivity(intent)
-                            activity.overridePendingTransition(R.anim.slide_from_right, R.anim.slide_to_left)
-                        }
-                        true
-                    }
+                    fragment = "com.keylesspalace.tusky.components.preference.TabFilterPreferencesFragment"
                 }
             }
 
@@ -259,14 +252,7 @@ class PreferencesFragment : PreferenceFragmentCompat(), Injectable {
             preferenceCategory(R.string.pref_title_proxy_settings) {
                 httpProxyPref = preference {
                     setTitle(R.string.pref_title_http_proxy_settings)
-                    setOnPreferenceClickListener {
-                        activity?.let { activity ->
-                            val intent = PreferencesActivity.newIntent(activity, PreferencesActivity.PROXY_PREFERENCES)
-                            activity.startActivity(intent)
-                            activity.overridePendingTransition(R.anim.slide_from_right, R.anim.slide_to_left)
-                        }
-                        true
-                    }
+                    fragment = "com.keylesspalace.tusky.components.preference.ProxyPreferencesFragment"
                 }
             }
         }
@@ -278,6 +264,7 @@ class PreferencesFragment : PreferenceFragmentCompat(), Injectable {
 
     override fun onResume() {
         super.onResume()
+        requireActivity().setTitle(R.string.action_view_preferences)
         updateHttpProxySummary()
     }
 

app/src/main/java/com/keylesspalace/tusky/components/preference/ProxyPreferencesFragment.kt

@@ -65,6 +65,11 @@ class ProxyPreferencesFragment : PreferenceFragmentCompat() {
         }
     }
 
+    override fun onResume() {
+        super.onResume()
+        requireActivity().setTitle(R.string.pref_title_http_proxy_settings)
+    }
+
     override fun onPause() {
         super.onPause()
         if (pendingRestart) {

app/src/main/java/com/keylesspalace/tusky/components/preference/TabFilterPreferencesFragment.kt

@@ -46,6 +46,11 @@ class TabFilterPreferencesFragment : PreferenceFragmentCompat() {
         }
     }
 
+    override fun onResume() {
+        super.onResume()
+        requireActivity().setTitle(R.string.pref_title_post_tabs)
+    }
+
     companion object {
         fun newInstance(): TabFilterPreferencesFragment {
             return TabFilterPreferencesFragment()