Remove card stack

Obsoletes a bunch of convoluted and probably brittle fragment management
code.

b/22179367

Change-Id: I3aa17c3d7e682c6a54710561bb877f3d7a8550df

6 files changed, 51 insertions, 197 deletions

diff --git a/v17/preference-leanback/api/current.txt b/v17/preference-leanback/api/current.txt
index b31306ca7a..675a18ecee 100644
--- a/v17/preference-leanback/api/current.txt
+++ b/v17/preference-leanback/api/current.txt
@@ -60,8 +60,8 @@ package android.support.v17.preference {
     ctor public LeanbackSettingsFragment();
     method public boolean onPreferenceDisplayDialog(android.support.v14.preference.PreferenceFragment, android.support.v7.preference.Preference);
     method public abstract void onPreferenceStartInitialScreen();
-    method public void startImmersiveFragment(android.app.Fragment, java.lang.String);
-    method public void startPreferenceFragment(android.app.Fragment, java.lang.String);
+    method public void startImmersiveFragment(android.app.Fragment);
+    method public void startPreferenceFragment(android.app.Fragment);
   }
 
 }
diff --git a/v17/preference-leanback/res/layout/leanback_settings_fragment.xml b/v17/preference-leanback/res/layout/leanback_settings_fragment.xml
index 5cf3e51813..e9c421ea26 100644
--- a/v17/preference-leanback/res/layout/leanback_settings_fragment.xml
+++ b/v17/preference-leanback/res/layout/leanback_settings_fragment.xml
@@ -15,6 +15,12 @@
   ~ limitations under the License
   -->
 <android.support.v17.preference.LeanbackSettingsRootView xmlns:android="http://schemas.android.com/apk/res/android"
-    android:id="@+id/settings_fragment_container"
+    android:id="@+id/settings_dialog_container"
     android:layout_width="match_parent"
-    android:layout_height="match_parent"/>
+    android:layout_height="match_parent">
+    <FrameLayout
+        android:id="@+id/settings_preference_fragment_container"
+        android:layout_width="@dimen/lb_settings_pane_width"
+        android:layout_height="match_parent"
+        android:layout_gravity="end"/>
+</android.support.v17.preference.LeanbackSettingsRootView>
diff --git a/v17/preference-leanback/res/layout/leanback_settings_fragment_stack.xml b/v17/preference-leanback/res/layout/leanback_settings_fragment_stack.xml
deleted file mode 100644
index 568c41e353..0000000000
--- a/v17/preference-leanback/res/layout/leanback_settings_fragment_stack.xml
+++ /dev/null
@@ -1,26 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!--
-  ~ Copyright (C) 2015 The Android Open Source Project
-  ~
-  ~ Licensed under the Apache License, Version 2.0 (the "License");
-  ~ you may not use this file except in compliance with the License.
-  ~ You may obtain a copy of the License at
-  ~
-  ~      http://www.apache.org/licenses/LICENSE-2.0
-  ~
-  ~ Unless required by applicable law or agreed to in writing, software
-  ~ distributed under the License is distributed on an "AS IS" BASIS,
-  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  ~ See the License for the specific language governing permissions and
-  ~ limitations under the License
-  -->
-<android.support.v17.leanback.view.StackedLayout
-    xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:app="http://schemas.android.com/apk/res-auto"
-    android:id="@+id/settings_preference_stack"
-    android:layout_width="match_parent"
-    android:layout_height="match_parent"
-    app:cardWidth="@dimen/lb_settings_card_width"
-    app:stackShift="@dimen/lb_settings_card_shift"
-    app:elevationIncrement="@dimen/lb_settings_card_elevation"
-    />
diff --git a/v17/preference-leanback/res/values/dimens.xml b/v17/preference-leanback/res/values/dimens.xml
index c3e519fb63..49763fe4fa 100644
--- a/v17/preference-leanback/res/values/dimens.xml
+++ b/v17/preference-leanback/res/values/dimens.xml
@@ -21,7 +21,5 @@
   <dimen name="lb_preference_decor_title_padding_end">56dp</dimen>
   <dimen name="lb_preference_decor_title_text_size">20sp</dimen>
 
-  <dimen name="lb_settings_card_width">360dp</dimen>
-  <dimen name="lb_settings_card_shift">72dp</dimen>
-  <dimen name="lb_settings_card_elevation">12dp</dimen>
+  <dimen name="lb_settings_pane_width">360dp</dimen>
 </resources>
diff --git a/v17/preference-leanback/src/android/support/v17/preference/BaseLeanbackPreferenceFragment.java b/v17/preference-leanback/src/android/support/v17/preference/BaseLeanbackPreferenceFragment.java
index 40d9607239..6fc1fa6f16 100644
--- a/v17/preference-leanback/src/android/support/v17/preference/BaseLeanbackPreferenceFragment.java
+++ b/v17/preference-leanback/src/android/support/v17/preference/BaseLeanbackPreferenceFragment.java
@@ -16,6 +16,7 @@
 
 package android.support.v17.preference;
 
+import android.app.Fragment;
 import android.os.Bundle;
 import android.support.v14.preference.PreferenceFragment;
 import android.support.v17.leanback.widget.VerticalGridView;
@@ -38,4 +39,12 @@ public abstract class BaseLeanbackPreferenceFragment extends PreferenceFragment
         verticalGridView.setFocusScrollStrategy(VerticalGridView.FOCUS_SCROLL_ALIGNED);
         return verticalGridView;
     }
+
+    /**
+     * @hide
+     */
+    @Override
+    public Fragment getCallbackFragment() {
+        return getParentFragment();
+    }
 }
diff --git a/v17/preference-leanback/src/android/support/v17/preference/LeanbackSettingsFragment.java b/v17/preference-leanback/src/android/support/v17/preference/LeanbackSettingsFragment.java
index 38ef3d9b80..c6a7e94683 100644
--- a/v17/preference-leanback/src/android/support/v17/preference/LeanbackSettingsFragment.java
+++ b/v17/preference-leanback/src/android/support/v17/preference/LeanbackSettingsFragment.java
@@ -20,12 +20,10 @@ import android.app.Fragment;
 import android.app.FragmentTransaction;
 import android.os.Bundle;
 import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
 import android.support.v14.preference.MultiSelectListPreference;
 import android.support.v14.preference.PreferenceFragment;
 import android.support.v7.preference.ListPreference;
 import android.support.v7.preference.Preference;
-import android.support.v7.preference.PreferenceScreen;
 import android.view.KeyEvent;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -36,10 +34,8 @@ public abstract class LeanbackSettingsFragment extends Fragment
         PreferenceFragment.OnPreferenceStartScreenCallback,
         PreferenceFragment.OnPreferenceDisplayDialogCallback {
 
-    private static final String SETTINGS_FRAGMENT_INNER_TAG =
-            "android.support.v17.preference.LeanbackSettingsFragment.INNER_FRAGMENT";
-
-    private boolean mInitialScreen;
+    private static final String PREFERENCE_FRAGMENT_TAG =
+            "android.support.v17.preference.LeanbackSettingsFragment.PREFERENCE_FRAGMENT";
 
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container,
@@ -56,14 +52,7 @@ public abstract class LeanbackSettingsFragment extends Fragment
     public void onViewCreated(View view, Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
         if (savedInstanceState == null) {
-            final Fragment f = new LeanbackSettingsFragmentInner();
-            getChildFragmentManager().beginTransaction()
-                    .add(R.id.settings_fragment_container, f, SETTINGS_FRAGMENT_INNER_TAG)
-                    .commit();
-            getChildFragmentManager().executePendingTransactions();
-            mInitialScreen = true;
             onPreferenceStartInitialScreen();
-            mInitialScreen = false;
         }
     }
 
@@ -73,11 +62,11 @@ public abstract class LeanbackSettingsFragment extends Fragment
         if (pref instanceof ListPreference) {
             final ListPreference listPreference = (ListPreference) pref;
             f = LeanbackListPreferenceDialogFragment.newInstanceSingle(listPreference.getKey());
-            getInnerFragment().startDialogFragment(f, caller, null);
+            startImmersiveFragment(f);
         } else if (pref instanceof MultiSelectListPreference) {
             MultiSelectListPreference listPreference = (MultiSelectListPreference) pref;
             f = LeanbackListPreferenceDialogFragment.newInstanceMulti(listPreference.getKey());
-            getInnerFragment().startDialogFragment(f, caller, null);
+            startImmersiveFragment(f);
         }
         // TODO
 //        else if (pref instanceof EditTextPreference) {
@@ -92,7 +81,7 @@ public abstract class LeanbackSettingsFragment extends Fragment
     /**
      * Called to instantiate the initial {@link android.support.v14.preference.PreferenceFragment}
      * to be shown in this fragment. Implementations are expected to call
-     * {@link #startPreferenceFragment(android.app.Fragment, java.lang.String)}.
+     * {@link #startPreferenceFragment(android.app.Fragment)}.
      */
     public abstract void onPreferenceStartInitialScreen();
 
@@ -101,171 +90,49 @@ public abstract class LeanbackSettingsFragment extends Fragment
      * list-style fragments on top of the stack of preference fragments.
      *
      * @param fragment Fragment instance to be added.
-     * @param tag Fragment tag
      */
-    public void startPreferenceFragment(@NonNull Fragment fragment, @Nullable String tag) {
-        getInnerFragment().startStackedFragment(fragment, tag, !mInitialScreen);
+    public void startPreferenceFragment(@NonNull Fragment fragment) {
+        fragment.setTargetFragment(this, 0);
+        final FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
+        final Fragment prevFragment =
+                getChildFragmentManager().findFragmentByTag(PREFERENCE_FRAGMENT_TAG);
+        if (prevFragment != null) {
+            transaction
+                    .addToBackStack(null)
+                    .replace(R.id.settings_preference_fragment_container, fragment,
+                            PREFERENCE_FRAGMENT_TAG);
+        } else {
+            transaction
+                    .add(R.id.settings_preference_fragment_container, fragment,
+                            PREFERENCE_FRAGMENT_TAG);
+        }
+        transaction.commit();
     }
 
     /**
      * Displays a fragment to the user, temporarily replacing the contents of this fragment.
      *
      * @param fragment Fragment instance to be added.
-     * @param tag Fragment tag
      */
-    public void startImmersiveFragment(@NonNull Fragment fragment, @Nullable String tag) {
-        getChildFragmentManager().beginTransaction()
-                .replace(R.id.settings_fragment_container, fragment, tag)
+    public void startImmersiveFragment(@NonNull Fragment fragment) {
+        final FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
+        final Fragment preferenceFragment =
+                getChildFragmentManager().findFragmentByTag(PREFERENCE_FRAGMENT_TAG);
+        if (preferenceFragment != null) {
+            transaction.hide(preferenceFragment);
+        }
+        transaction
+                .add(R.id.settings_dialog_container, fragment)
                 .addToBackStack(null)
                 .commit();
     }
 
-    private LeanbackSettingsFragmentInner getInnerFragment() {
-        return (LeanbackSettingsFragmentInner)
-                getChildFragmentManager().findFragmentByTag(SETTINGS_FRAGMENT_INNER_TAG);
-    }
-
-    private boolean handleBackPress() {
-        final LeanbackSettingsFragmentInner inner = getInnerFragment();
-        boolean handled = false;
-        if (inner != null && inner.isVisible()) {
-            handled = inner.handleBackPress();
-        }
-        return handled || getChildFragmentManager().popBackStackImmediate();
-    }
-
-    /**
-     * @hide
-     */
-    public static class LeanbackSettingsFragmentInner extends Fragment
-            implements LeanbackPreferenceDialogFragment.TargetFragment {
-
-        private static final String SAVESTATE_TARGET_PREF_FRAG =
-                "android.support.v17.preference.LeanbackSettingsFragment.TARGET_PREF_FRAG";
-
-        private static final String TARGET_FRAGMENT_TAG =
-                "android.support.v17.preference.LeanbackSettingsFragment.TARGET";
-
-        // Preference fragment which last launched a dialog
-        private PreferenceFragment mTargetPreferenceFragment;
-
-        @Override
-        public void onCreate(Bundle savedInstanceState) {
-            super.onCreate(savedInstanceState);
-
-            if (savedInstanceState != null &&
-                    savedInstanceState.containsKey(SAVESTATE_TARGET_PREF_FRAG)) {
-                mTargetPreferenceFragment = (PreferenceFragment) getChildFragmentManager()
-                        .getFragment(savedInstanceState, SAVESTATE_TARGET_PREF_FRAG);
-            }
-        }
-
-        @Override
-        public @Nullable View onCreateView(LayoutInflater inflater, ViewGroup container,
-                Bundle savedInstanceState) {
-            return inflater.inflate(R.layout.leanback_settings_fragment_stack,
-                    container, false);
-        }
-
-        @Override
-        public void onSaveInstanceState(Bundle outState) {
-            super.onSaveInstanceState(outState);
-            if (mTargetPreferenceFragment != null) {
-                getChildFragmentManager().putFragment(outState, SAVESTATE_TARGET_PREF_FRAG,
-                        mTargetPreferenceFragment);
-            }
-        }
-
-        public void startDialogFragment(@NonNull Fragment dialogFragment,
-                @NonNull PreferenceFragment requestingFragment, @Nullable String tag) {
-            mTargetPreferenceFragment = requestingFragment;
-            startFragment(dialogFragment, tag, true);
-        }
-
-        public void startStackedFragment(@NonNull Fragment fragment, @Nullable String tag,
-                boolean addToBackstack) {
-            fragment.setTargetFragment(findTarget(), 0);
-            startFragment(fragment, tag, addToBackstack);
-        }
-
-        private void startFragment(@NonNull Fragment fragment, @Nullable String tag,
-                boolean addToBackstack) {
-            final FragmentTransaction transaction = getChildFragmentManager().beginTransaction()
-                    .add(R.id.settings_preference_stack, fragment, tag);
-            if (addToBackstack) {
-                transaction.addToBackStack(null);
-            }
-            transaction.commit();
-        }
-
-        private Fragment findTarget() {
-            Fragment target =
-                    getChildFragmentManager().findFragmentByTag(TARGET_FRAGMENT_TAG);
-            if (target == null) {
-                target = new Target();
-                getChildFragmentManager().beginTransaction()
-                        .add(target, TARGET_FRAGMENT_TAG)
-                        .commit();
-                getChildFragmentManager().executePendingTransactions();
-            }
-            return target;
-        }
-
-        public boolean handleBackPress() {
-            return getChildFragmentManager().popBackStackImmediate();
-        }
-
-        public Preference findPreference(CharSequence key) {
-            return mTargetPreferenceFragment.findPreference(key);
-        }
-
-        public PreferenceFragment getPreferenceFragment() {
-            return mTargetPreferenceFragment;
-        }
-
-        @Override
-        public LeanbackSettingsFragment getSettingsFragment() {
-            return (LeanbackSettingsFragment) getParentFragment();
-        }
-
-        // This looks terrible, and it is. We need this because the target fragment needs to be
-        // in the same FragmentManager as the fragment targeting it.
-        /**
-         * @hide
-         */
-        public static class Target extends Fragment
-                implements PreferenceFragment.OnPreferenceStartFragmentCallback,
-                PreferenceFragment.OnPreferenceStartScreenCallback,
-                PreferenceFragment.OnPreferenceDisplayDialogCallback {
-
-            private LeanbackSettingsFragment getOuterParent() {
-                return (LeanbackSettingsFragment) getParentFragment().getParentFragment();
-            }
-
-            @Override
-            public boolean onPreferenceStartFragment(PreferenceFragment caller, Preference pref) {
-                return getOuterParent().onPreferenceStartFragment(caller, pref);
-            }
-
-            @Override
-            public boolean onPreferenceStartScreen(PreferenceFragment caller,
-                    PreferenceScreen pref) {
-                return getOuterParent().onPreferenceStartScreen(caller, pref);
-            }
-
-            @Override
-            public boolean onPreferenceDisplayDialog(PreferenceFragment caller, Preference pref) {
-                return getOuterParent().onPreferenceDisplayDialog(caller, pref);
-            }
-        }
-    }
-
     private class RootViewOnKeyListener implements View.OnKeyListener {
 
         @Override
         public boolean onKey(View v, int keyCode, KeyEvent event) {
             if (keyCode == KeyEvent.KEYCODE_BACK) {
-                return handleBackPress();
+                return getChildFragmentManager().popBackStackImmediate();
             } else {
                 return false;
             }