src/com/android/car/settings/common/BaseCarSettingsActivity.java - platform/packages/apps/Car/Settings - Git at Google

 /*
  * Copyright (C) 2019 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.
  */

 package com.android.car.settings.common;

 import static android.view.ViewGroup.FOCUS_BEFORE_DESCENDANTS;
 import static android.view.ViewGroup.FOCUS_BLOCK_DESCENDANTS;
 import static android.view.accessibility.AccessibilityNodeInfo.ACTION_FOCUS;

 import android.car.drivingstate.CarUxRestrictions;
 import android.car.drivingstate.CarUxRestrictionsManager;
 import android.car.drivingstate.CarUxRestrictionsManager.OnUxRestrictionsChangedListener;
 import android.content.Context;
 import android.content.Intent;
 import android.content.pm.ActivityInfo;
 import android.content.pm.PackageManager;
 import android.os.Bundle;
 import android.provider.Settings;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewTreeObserver;
 import android.view.inputmethod.InputMethodManager;
 import android.widget.Toast;

 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.fragment.app.DialogFragment;
 import androidx.fragment.app.Fragment;
 import androidx.fragment.app.FragmentActivity;
 import androidx.fragment.app.FragmentManager.OnBackStackChangedListener;
 import androidx.preference.Preference;
 import androidx.preference.PreferenceFragmentCompat;

 import com.android.car.apps.common.util.Themes;
 import com.android.car.settings.R;
 import com.android.car.settings.common.rotary.SettingsFocusParkingView;
 import com.android.car.ui.baselayout.Insets;
 import com.android.car.ui.baselayout.InsetsChangedListener;
 import com.android.car.ui.core.CarUi;
 import com.android.car.ui.toolbar.MenuItem;
 import com.android.car.ui.toolbar.NavButtonMode;
 import com.android.car.ui.toolbar.ToolbarController;
 import com.android.settingslib.core.lifecycle.HideNonSystemOverlayMixin;

 import java.util.Collections;
 import java.util.List;

 /**
  * Base activity class for car settings, provides a action bar with a back button that goes to
  * previous activity.
  */
 public abstract class BaseCarSettingsActivity extends FragmentActivity implements
         FragmentHost, OnUxRestrictionsChangedListener, UxRestrictionsProvider,
         OnBackStackChangedListener, PreferenceFragmentCompat.OnPreferenceStartFragmentCallback,
         InsetsChangedListener {

     /**
      * Meta data key for specifying the preference key of the top level menu preference that the
      * initial activity's fragment falls under. If this is not specified in the activity's
      * metadata, the top level menu preference will not be highlighted upon activity launch.
      */
     public static final String META_DATA_KEY_HEADER_KEY =
             "com.android.car.settings.TOP_LEVEL_HEADER_KEY";

     /**
      * Meta data key for specifying activities that should always be shown in the single pane
      * configuration. If not specified for the activity, the activity will default to the value
      * {@link R.bool.config_global_force_single_pane}.
      */
     public static final String META_DATA_KEY_SINGLE_PANE = "com.android.car.settings.SINGLE_PANE";

     private static final Logger LOG = new Logger(BaseCarSettingsActivity.class);
     private static final int SEARCH_REQUEST_CODE = 501;
     private static final String KEY_HAS_NEW_INTENT = "key_has_new_intent";

     private boolean mHasNewIntent = true;
     private boolean mHasInitialFocus = false;
     private boolean mIsInitialFragmentTransaction = true;

     private String mTopLevelHeaderKey;
     private boolean mIsSinglePane;

     private ToolbarController mGlobalToolbar;
     private ToolbarController mMiniToolbar;

     private CarUxRestrictionsHelper mUxRestrictionsHelper;
     private ViewGroup mFragmentContainer;
     private View mRestrictedMessage;
     // Default to minimum restriction.
     private CarUxRestrictions mCarUxRestrictions = new CarUxRestrictions.Builder(
             /* reqOpt= */ true,
             CarUxRestrictions.UX_RESTRICTIONS_BASELINE,
             /* timestamp= */ 0
     ).build();

     private ViewTreeObserver.OnGlobalLayoutListener mGlobalLayoutListener;
     private final ViewTreeObserver.OnGlobalFocusChangeListener mFocusChangeListener =
             (oldFocus, newFocus) -> {
                 if (oldFocus instanceof SettingsFocusParkingView) {
                     // Focus is manually shifted away from the SettingsFocusParkingView.
                     // Therefore, the focus should no longer shift upon global layout.
                     removeGlobalLayoutListener();
                 }
                 if (newFocus instanceof SettingsFocusParkingView && mGlobalLayoutListener == null) {
                     // Attempting to shift focus to the SettingsFocusParkingView without a layout
                     // listener is not allowed, since it can cause undermined focus behavior
                     // in these rare edge cases.
                     requestTopLevelMenuFocus();
                 }

                 // This will maintain focus in the content pane if a view goes from
                 // focusable -> unfocusable.
                 if (oldFocus == null && mHasInitialFocus) {
                     requestContentPaneFocus();
                 } else {
                     mHasInitialFocus = true;
                 }
             };

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         getLifecycle().addObserver(new HideNonSystemOverlayMixin(this));
         if (savedInstanceState != null) {
             mHasNewIntent = savedInstanceState.getBoolean(KEY_HAS_NEW_INTENT, mHasNewIntent);
         }
         populateMetaData();
         setContentView(R.layout.car_setting_activity);
         mFragmentContainer = findViewById(R.id.fragment_container);

         // We do this so that the insets are not automatically sent to the fragments.
         // The fragments have their own insets handled by the installBaseLayoutAround() method.
         CarUi.replaceInsetsChangedListenerWith(this, this);

         setUpToolbars();
         getSupportFragmentManager().addOnBackStackChangedListener(this);
         mRestrictedMessage = findViewById(R.id.restricted_message);

         if (mHasNewIntent) {
             launchIfDifferent(getInitialFragment());
             mHasNewIntent = false;
         } else if (!mIsSinglePane) {
             updateMiniToolbarState();
         }
         mUxRestrictionsHelper = new CarUxRestrictionsHelper(/* context= */ this, /* listener= */
                 this);

         if (shouldFocusContentOnLaunch()) {
             requestContentPaneFocus();
             mHasInitialFocus = true;
         } else {
             requestTopLevelMenuFocus();
         }
         setUpFocusChangeListener(true);
     }

     @Override
     protected void onSaveInstanceState(@NonNull Bundle outState) {
         super.onSaveInstanceState(outState);
         outState.putBoolean(KEY_HAS_NEW_INTENT, mHasNewIntent);
     }

     @Override
     public void onDestroy() {
         setUpFocusChangeListener(false);
         removeGlobalLayoutListener();
         mUxRestrictionsHelper.destroy();
         mUxRestrictionsHelper = null;
         super.onDestroy();
     }

     @Override
     public void onBackPressed() {
         super.onBackPressed();
         hideKeyboard();
         // If the backstack is empty, finish the activity.
         if (getSupportFragmentManager().getBackStackEntryCount() == 0) {
             finish();
         }
     }

     @Override
     public Intent getIntent() {
         Intent superIntent = super.getIntent();
         if (mTopLevelHeaderKey != null) {
             superIntent.putExtra(META_DATA_KEY_HEADER_KEY, mTopLevelHeaderKey);
         }
         superIntent.putExtra(META_DATA_KEY_SINGLE_PANE, mIsSinglePane);
         return superIntent;
     }

     @Override
     public void launchFragment(Fragment fragment) {
         if (fragment instanceof DialogFragment) {
             throw new IllegalArgumentException(
                     "cannot launch dialogs with launchFragment() - use showDialog() instead");
         }

         if (mIsSinglePane) {
             Intent intent = SubSettingsActivity.newInstance(/* context= */ this, fragment);
             startActivity(intent);
         } else {
             launchFragmentInternal(fragment);
         }
     }

     protected void launchFragmentInternal(Fragment fragment) {
         getSupportFragmentManager()
                 .beginTransaction()
                 .setCustomAnimations(
                         Themes.getAttrResourceId(/* context= */ this,
                                 android.R.attr.fragmentOpenEnterAnimation),
                         Themes.getAttrResourceId(/* context= */ this,
                                 android.R.attr.fragmentOpenExitAnimation),
                         Themes.getAttrResourceId(/* context= */ this,
                                 android.R.attr.fragmentCloseEnterAnimation),
                         Themes.getAttrResourceId(/* context= */ this,
                                 android.R.attr.fragmentCloseExitAnimation))
                 .replace(R.id.fragment_container, fragment,
                         Integer.toString(getSupportFragmentManager().getBackStackEntryCount()))
                 .addToBackStack(null)
                 .commit();
     }

     @Override
     public void goBack() {
         onBackPressed();
     }

     @Override
     public void showBlockingMessage() {
         Toast.makeText(this, R.string.restricted_while_driving, Toast.LENGTH_SHORT).show();
     }

     @Override
     public ToolbarController getToolbar() {
         if (mIsSinglePane) {
             return mGlobalToolbar;
         }
         return mMiniToolbar;
     }

     @Override
     public void onUxRestrictionsChanged(CarUxRestrictions restrictionInfo) {
         mCarUxRestrictions = restrictionInfo;

         // Update restrictions for current fragment.
         Fragment currentFragment = getCurrentFragment();
         if (currentFragment instanceof OnUxRestrictionsChangedListener) {
             ((OnUxRestrictionsChangedListener) currentFragment)
                     .onUxRestrictionsChanged(restrictionInfo);
         }
         updateBlockingView(currentFragment);

         if (!mIsSinglePane) {
             // Update restrictions for top level menu (if present).
             Fragment topLevelMenu =
                     getSupportFragmentManager().findFragmentById(R.id.top_level_menu);
             if (topLevelMenu instanceof CarUxRestrictionsManager.OnUxRestrictionsChangedListener) {
                 ((CarUxRestrictionsManager.OnUxRestrictionsChangedListener) topLevelMenu)
                         .onUxRestrictionsChanged(restrictionInfo);
             }
         }
     }

     @Override
     public CarUxRestrictions getCarUxRestrictions() {
         return mCarUxRestrictions;
     }

     @Override
     public void onBackStackChanged() {
         onUxRestrictionsChanged(getCarUxRestrictions());
         if (!mIsSinglePane) {
             if (mHasInitialFocus && shouldFocusContentOnBackstackChange()) {
                 requestContentPaneFocus();
             }
             updateMiniToolbarState();
         }
     }

     @Override
     public void onCarUiInsetsChanged(Insets insets) {
         // intentional no-op - insets are handled by the listeners created during toolbar setup
     }

     @Override
     public boolean onPreferenceStartFragment(PreferenceFragmentCompat caller, Preference pref) {
         if (pref.getFragment() != null) {
             Fragment fragment = Fragment.instantiate(/* context= */ this, pref.getFragment(),
                     pref.getExtras());
             launchFragment(fragment);
             return true;
         }
         return false;
     }

     /**
      * Gets the fragment to show onCreate. If null, the activity will not perform an initial
      * fragment transaction.
      */
     @Nullable
     protected abstract Fragment getInitialFragment();

     protected Fragment getCurrentFragment() {
         return getSupportFragmentManager().findFragmentById(R.id.fragment_container);
     }

     /**
      * Returns whether the content pane should get focus initially when in dual-pane configuration.
      */
     protected boolean shouldFocusContentOnLaunch() {
         return true;
     }

     private void launchIfDifferent(Fragment newFragment) {
         Fragment currentFragment = getCurrentFragment();
         if ((newFragment != null) && differentFragment(newFragment, currentFragment)) {
             LOG.d("launchIfDifferent: " + newFragment + " replacing " + currentFragment);
             launchFragmentInternal(newFragment);
         }
     }

     /**
      * Returns {code true} if newFragment is different from current fragment.
      */
     private boolean differentFragment(Fragment newFragment, Fragment currentFragment) {
         return (currentFragment == null)
                 || (!currentFragment.getClass().equals(newFragment.getClass()));
     }

     private void hideKeyboard() {
         InputMethodManager imm = (InputMethodManager) this.getSystemService(
                 Context.INPUT_METHOD_SERVICE);
         imm.hideSoftInputFromWindow(getWindow().getDecorView().getWindowToken(), 0);
     }

     private void updateBlockingView(@Nullable Fragment currentFragment) {
         if (mRestrictedMessage == null) {
             return;
         }
         if (currentFragment instanceof BaseFragment
                 && !((BaseFragment) currentFragment).canBeShown(mCarUxRestrictions)) {
             mRestrictedMessage.setVisibility(View.VISIBLE);
             mFragmentContainer.setDescendantFocusability(FOCUS_BLOCK_DESCENDANTS);
             mFragmentContainer.clearFocus();
             hideKeyboard();
         } else {
             mRestrictedMessage.setVisibility(View.GONE);
             mFragmentContainer.setDescendantFocusability(FOCUS_BEFORE_DESCENDANTS);
         }
     }

     private void populateMetaData() {
         try {
             ActivityInfo ai = getPackageManager().getActivityInfo(getComponentName(),
                     PackageManager.GET_META_DATA);
             if (ai == null || ai.metaData == null) {
                 mIsSinglePane = getResources().getBoolean(R.bool.config_global_force_single_pane);
                 return;
             }
             mTopLevelHeaderKey = ai.metaData.getString(META_DATA_KEY_HEADER_KEY);
             mIsSinglePane = ai.metaData.getBoolean(META_DATA_KEY_SINGLE_PANE,
                     getResources().getBoolean(R.bool.config_global_force_single_pane));
         } catch (PackageManager.NameNotFoundException e) {
             LOG.w("Unable to find package", e);
         }
     }

     private void setUpToolbars() {
         View globalToolbarWrappedView = mIsSinglePane ? findViewById(
                 R.id.fragment_container_wrapper) : findViewById(R.id.top_level_menu_container);
         mGlobalToolbar = CarUi.installBaseLayoutAround(
                 globalToolbarWrappedView,
                 insets -> globalToolbarWrappedView.setPadding(
                         insets.getLeft(), insets.getTop(), insets.getRight(),
                         insets.getBottom()), /* hasToolbar= */ true);
         if (mIsSinglePane) {
             mGlobalToolbar.setNavButtonMode(NavButtonMode.BACK);
             findViewById(R.id.top_level_menu_container).setVisibility(View.GONE);
             findViewById(R.id.top_level_divider).setVisibility(View.GONE);
             return;
         }
         mMiniToolbar = CarUi.installBaseLayoutAround(
                 findViewById(R.id.fragment_container_wrapper),
                 insets -> findViewById(R.id.fragment_container_wrapper).setPadding(
                         insets.getLeft(), insets.getTop(), insets.getRight(),
                         insets.getBottom()), /* hasToolbar= */ true);

         MenuItem searchButton = new MenuItem.Builder(this)
                 .setToSearch()
                 .setOnClickListener(i -> onSearchButtonClicked())
                 .setUxRestrictions(CarUxRestrictions.UX_RESTRICTIONS_NO_KEYBOARD)
                 .setId(R.id.toolbar_menu_item_0)
                 .build();
         List<MenuItem> items = Collections.singletonList(searchButton);

         mGlobalToolbar.setTitle(R.string.settings_label);
         mGlobalToolbar.setNavButtonMode(NavButtonMode.DISABLED);
         mGlobalToolbar.setLogo(R.drawable.ic_launcher_settings);
         mGlobalToolbar.setMenuItems(items);
     }

     private void updateMiniToolbarState() {
         if (mMiniToolbar == null) {
             return;
         }
         if (getSupportFragmentManager().getBackStackEntryCount() > 1 || !isTaskRoot()) {
             mMiniToolbar.setNavButtonMode(NavButtonMode.BACK);
         } else {
             mMiniToolbar.setNavButtonMode(NavButtonMode.DISABLED);
         }
     }

     private void setUpFocusChangeListener(boolean enable) {
         if (mIsSinglePane) {
             // The focus change listener is only needed with two panes.
             return;
         }
         ViewTreeObserver observer = findViewById(
                 R.id.car_settings_activity_wrapper).getViewTreeObserver();
         if (enable) {
             observer.addOnGlobalFocusChangeListener(mFocusChangeListener);
         } else {
             observer.removeOnGlobalFocusChangeListener(mFocusChangeListener);
         }
     }

     private void requestTopLevelMenuFocus() {
         if (mIsSinglePane) {
             return;
         }
         Fragment topLevelMenu = getSupportFragmentManager().findFragmentById(R.id.top_level_menu);
         if (topLevelMenu == null) {
             return;
         }
         View fragmentView = topLevelMenu.getView();
         if (fragmentView == null) {
             return;
         }
         View focusArea = fragmentView.findViewById(R.id.settings_car_ui_focus_area);
         if (focusArea == null) {
             return;
         }
         removeGlobalLayoutListener();
         mGlobalLayoutListener = () -> {
             if (focusArea.isInTouchMode() || focusArea.hasFocus()) {
                 return;
             }
             focusArea.performAccessibilityAction(ACTION_FOCUS, /* arguments= */ null);
             removeGlobalLayoutListener();
         };
         fragmentView.getViewTreeObserver().addOnGlobalLayoutListener(mGlobalLayoutListener);
     }

     private void requestContentPaneFocus() {
         if (mIsSinglePane) {
             return;
         }
         if (getCurrentFragment() == null) {
             return;
         }
         View fragmentView = getCurrentFragment().getView();
         if (fragmentView == null) {
             return;
         }
         removeGlobalLayoutListener();
         if (fragmentView.isInTouchMode()) {
             mHasInitialFocus = false;
             return;
         }
         View focusArea = fragmentView.findViewById(R.id.settings_car_ui_focus_area);

         if (focusArea == null) {
             focusArea = fragmentView.findViewById(R.id.settings_content_focus_area);
             if (focusArea == null) {
                 return;
             }
         }
         removeGlobalLayoutListener();
         View finalFocusArea = focusArea; // required to be effectively final for inner class access
         mGlobalLayoutListener = () -> {
             if (finalFocusArea.isInTouchMode() || finalFocusArea.hasFocus()) {
                 return;
             }
             boolean success = finalFocusArea.performAccessibilityAction(
                     ACTION_FOCUS, /* arguments= */ null);
             if (success) {
                 removeGlobalLayoutListener();
             } else {
                 findViewById(
                         R.id.settings_focus_parking_view).performAccessibilityAction(
                         ACTION_FOCUS, /* arguments= */ null);
             }
         };
         fragmentView.getViewTreeObserver().addOnGlobalLayoutListener(mGlobalLayoutListener);
     }

     private boolean shouldFocusContentOnBackstackChange() {
         // We don't want to reset mHasInitialFocus when initial fragment is added
         if (mIsInitialFragmentTransaction && getInitialFragment() != null) {
             mIsInitialFragmentTransaction = false;
             return false;
         }

         return true;
     }

     private void removeGlobalLayoutListener() {
         if (mGlobalLayoutListener == null) {
             return;
         }

         // Check content pane
         Fragment contentFragment = getCurrentFragment();
         if (contentFragment != null && contentFragment.getView() != null) {
             contentFragment.getView().getViewTreeObserver()
                     .removeOnGlobalLayoutListener(mGlobalLayoutListener);
         }

         // Check top level menu
         Fragment topLevelMenu = getSupportFragmentManager().findFragmentById(R.id.top_level_menu);
         if (topLevelMenu != null && topLevelMenu.getView() != null) {
             topLevelMenu.getView().getViewTreeObserver()
                     .removeOnGlobalLayoutListener(mGlobalLayoutListener);
         }

         mGlobalLayoutListener = null;
     }

     private void onSearchButtonClicked() {
         Intent intent = new Intent(Settings.ACTION_APP_SEARCH_SETTINGS)
                 .setPackage(getSettingsIntelligencePkgName());
         if (intent.resolveActivity(getPackageManager()) == null) {
             return;
         }
         startActivityForResult(intent, SEARCH_REQUEST_CODE);
     }

     private String getSettingsIntelligencePkgName() {
         return getString(R.string.config_settingsintelligence_package_name);
     }
 }
	/*
	* Copyright (C) 2019 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.
	*/

	package com.android.car.settings.common;

	import static android.view.ViewGroup.FOCUS_BEFORE_DESCENDANTS;
	import static android.view.ViewGroup.FOCUS_BLOCK_DESCENDANTS;
	import static android.view.accessibility.AccessibilityNodeInfo.ACTION_FOCUS;

	import android.car.drivingstate.CarUxRestrictions;
	import android.car.drivingstate.CarUxRestrictionsManager;
	import android.car.drivingstate.CarUxRestrictionsManager.OnUxRestrictionsChangedListener;
	import android.content.Context;
	import android.content.Intent;
	import android.content.pm.ActivityInfo;
	import android.content.pm.PackageManager;
	import android.os.Bundle;
	import android.provider.Settings;
	import android.view.View;
	import android.view.ViewGroup;
	import android.view.ViewTreeObserver;
	import android.view.inputmethod.InputMethodManager;
	import android.widget.Toast;

	import androidx.annotation.NonNull;
	import androidx.annotation.Nullable;
	import androidx.fragment.app.DialogFragment;
	import androidx.fragment.app.Fragment;
	import androidx.fragment.app.FragmentActivity;
	import androidx.fragment.app.FragmentManager.OnBackStackChangedListener;
	import androidx.preference.Preference;
	import androidx.preference.PreferenceFragmentCompat;

	import com.android.car.apps.common.util.Themes;
	import com.android.car.settings.R;
	import com.android.car.settings.common.rotary.SettingsFocusParkingView;
	import com.android.car.ui.baselayout.Insets;
	import com.android.car.ui.baselayout.InsetsChangedListener;
	import com.android.car.ui.core.CarUi;
	import com.android.car.ui.toolbar.MenuItem;
	import com.android.car.ui.toolbar.NavButtonMode;
	import com.android.car.ui.toolbar.ToolbarController;
	import com.android.settingslib.core.lifecycle.HideNonSystemOverlayMixin;

	import java.util.Collections;
	import java.util.List;

	/**
	* Base activity class for car settings, provides a action bar with a back button that goes to
	* previous activity.
	*/
	public abstract class BaseCarSettingsActivity extends FragmentActivity implements
	FragmentHost, OnUxRestrictionsChangedListener, UxRestrictionsProvider,
	OnBackStackChangedListener, PreferenceFragmentCompat.OnPreferenceStartFragmentCallback,
	InsetsChangedListener {

	/**
	* Meta data key for specifying the preference key of the top level menu preference that the
	* initial activity's fragment falls under. If this is not specified in the activity's
	* metadata, the top level menu preference will not be highlighted upon activity launch.
	*/
	public static final String META_DATA_KEY_HEADER_KEY =
	"com.android.car.settings.TOP_LEVEL_HEADER_KEY";

	/**
	* Meta data key for specifying activities that should always be shown in the single pane
	* configuration. If not specified for the activity, the activity will default to the value
	* {@link R.bool.config_global_force_single_pane}.
	*/
	public static final String META_DATA_KEY_SINGLE_PANE = "com.android.car.settings.SINGLE_PANE";

	private static final Logger LOG = new Logger(BaseCarSettingsActivity.class);
	private static final int SEARCH_REQUEST_CODE = 501;
	private static final String KEY_HAS_NEW_INTENT = "key_has_new_intent";

	private boolean mHasNewIntent = true;
	private boolean mHasInitialFocus = false;
	private boolean mIsInitialFragmentTransaction = true;

	private String mTopLevelHeaderKey;
	private boolean mIsSinglePane;

	private ToolbarController mGlobalToolbar;
	private ToolbarController mMiniToolbar;

	private CarUxRestrictionsHelper mUxRestrictionsHelper;
	private ViewGroup mFragmentContainer;
	private View mRestrictedMessage;
	// Default to minimum restriction.
	private CarUxRestrictions mCarUxRestrictions = new CarUxRestrictions.Builder(
	/* reqOpt= */ true,
	CarUxRestrictions.UX_RESTRICTIONS_BASELINE,
	/* timestamp= */ 0
	).build();

	private ViewTreeObserver.OnGlobalLayoutListener mGlobalLayoutListener;
	private final ViewTreeObserver.OnGlobalFocusChangeListener mFocusChangeListener =
	(oldFocus, newFocus) -> {
	if (oldFocus instanceof SettingsFocusParkingView) {
	// Focus is manually shifted away from the SettingsFocusParkingView.
	// Therefore, the focus should no longer shift upon global layout.
	removeGlobalLayoutListener();
	}
	if (newFocus instanceof SettingsFocusParkingView && mGlobalLayoutListener == null) {
	// Attempting to shift focus to the SettingsFocusParkingView without a layout
	// listener is not allowed, since it can cause undermined focus behavior
	// in these rare edge cases.
	requestTopLevelMenuFocus();
	}

	// This will maintain focus in the content pane if a view goes from
	// focusable -> unfocusable.
	if (oldFocus == null && mHasInitialFocus) {
	requestContentPaneFocus();
	} else {
	mHasInitialFocus = true;
	}
	};

	@Override
	protected void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);
	getLifecycle().addObserver(new HideNonSystemOverlayMixin(this));
	if (savedInstanceState != null) {
	mHasNewIntent = savedInstanceState.getBoolean(KEY_HAS_NEW_INTENT, mHasNewIntent);
	}
	populateMetaData();
	setContentView(R.layout.car_setting_activity);
	mFragmentContainer = findViewById(R.id.fragment_container);

	// We do this so that the insets are not automatically sent to the fragments.
	// The fragments have their own insets handled by the installBaseLayoutAround() method.
	CarUi.replaceInsetsChangedListenerWith(this, this);

	setUpToolbars();
	getSupportFragmentManager().addOnBackStackChangedListener(this);
	mRestrictedMessage = findViewById(R.id.restricted_message);

	if (mHasNewIntent) {
	launchIfDifferent(getInitialFragment());
	mHasNewIntent = false;
	} else if (!mIsSinglePane) {
	updateMiniToolbarState();
	}
	mUxRestrictionsHelper = new CarUxRestrictionsHelper(/* context= / this, / listener= */
	this);

	if (shouldFocusContentOnLaunch()) {
	requestContentPaneFocus();
	mHasInitialFocus = true;
	} else {
	requestTopLevelMenuFocus();
	}
	setUpFocusChangeListener(true);
	}

	@Override
	protected void onSaveInstanceState(@NonNull Bundle outState) {
	super.onSaveInstanceState(outState);
	outState.putBoolean(KEY_HAS_NEW_INTENT, mHasNewIntent);
	}

	@Override
	public void onDestroy() {
	setUpFocusChangeListener(false);
	removeGlobalLayoutListener();
	mUxRestrictionsHelper.destroy();
	mUxRestrictionsHelper = null;
	super.onDestroy();
	}

	@Override
	public void onBackPressed() {
	super.onBackPressed();
	hideKeyboard();
	// If the backstack is empty, finish the activity.
	if (getSupportFragmentManager().getBackStackEntryCount() == 0) {
	finish();
	}
	}

	@Override
	public Intent getIntent() {
	Intent superIntent = super.getIntent();
	if (mTopLevelHeaderKey != null) {
	superIntent.putExtra(META_DATA_KEY_HEADER_KEY, mTopLevelHeaderKey);
	}
	superIntent.putExtra(META_DATA_KEY_SINGLE_PANE, mIsSinglePane);
	return superIntent;
	}

	@Override
	public void launchFragment(Fragment fragment) {
	if (fragment instanceof DialogFragment) {
	throw new IllegalArgumentException(
	"cannot launch dialogs with launchFragment() - use showDialog() instead");
	}

	if (mIsSinglePane) {
	Intent intent = SubSettingsActivity.newInstance(/* context= */ this, fragment);
	startActivity(intent);
	} else {
	launchFragmentInternal(fragment);
	}
	}

	protected void launchFragmentInternal(Fragment fragment) {
	getSupportFragmentManager()
	.beginTransaction()
	.setCustomAnimations(
	Themes.getAttrResourceId(/* context= */ this,
	android.R.attr.fragmentOpenEnterAnimation),
	Themes.getAttrResourceId(/* context= */ this,
	android.R.attr.fragmentOpenExitAnimation),
	Themes.getAttrResourceId(/* context= */ this,
	android.R.attr.fragmentCloseEnterAnimation),
	Themes.getAttrResourceId(/* context= */ this,
	android.R.attr.fragmentCloseExitAnimation))
	.replace(R.id.fragment_container, fragment,
	Integer.toString(getSupportFragmentManager().getBackStackEntryCount()))
	.addToBackStack(null)
	.commit();
	}

	@Override
	public void goBack() {
	onBackPressed();
	}

	@Override
	public void showBlockingMessage() {
	Toast.makeText(this, R.string.restricted_while_driving, Toast.LENGTH_SHORT).show();
	}

	@Override
	public ToolbarController getToolbar() {
	if (mIsSinglePane) {
	return mGlobalToolbar;
	}
	return mMiniToolbar;
	}

	@Override
	public void onUxRestrictionsChanged(CarUxRestrictions restrictionInfo) {
	mCarUxRestrictions = restrictionInfo;

	// Update restrictions for current fragment.
	Fragment currentFragment = getCurrentFragment();
	if (currentFragment instanceof OnUxRestrictionsChangedListener) {
	((OnUxRestrictionsChangedListener) currentFragment)
	.onUxRestrictionsChanged(restrictionInfo);
	}
	updateBlockingView(currentFragment);

	if (!mIsSinglePane) {
	// Update restrictions for top level menu (if present).
	Fragment topLevelMenu =
	getSupportFragmentManager().findFragmentById(R.id.top_level_menu);
	if (topLevelMenu instanceof CarUxRestrictionsManager.OnUxRestrictionsChangedListener) {
	((CarUxRestrictionsManager.OnUxRestrictionsChangedListener) topLevelMenu)
	.onUxRestrictionsChanged(restrictionInfo);
	}
	}
	}

	@Override
	public CarUxRestrictions getCarUxRestrictions() {
	return mCarUxRestrictions;
	}

	@Override
	public void onBackStackChanged() {
	onUxRestrictionsChanged(getCarUxRestrictions());
	if (!mIsSinglePane) {
	if (mHasInitialFocus && shouldFocusContentOnBackstackChange()) {
	requestContentPaneFocus();
	}
	updateMiniToolbarState();
	}
	}

	@Override
	public void onCarUiInsetsChanged(Insets insets) {
	// intentional no-op - insets are handled by the listeners created during toolbar setup
	}

	@Override
	public boolean onPreferenceStartFragment(PreferenceFragmentCompat caller, Preference pref) {
	if (pref.getFragment() != null) {
	Fragment fragment = Fragment.instantiate(/* context= */ this, pref.getFragment(),
	pref.getExtras());
	launchFragment(fragment);
	return true;
	}
	return false;
	}

	/**
	* Gets the fragment to show onCreate. If null, the activity will not perform an initial
	* fragment transaction.
	*/
	@Nullable
	protected abstract Fragment getInitialFragment();

	protected Fragment getCurrentFragment() {
	return getSupportFragmentManager().findFragmentById(R.id.fragment_container);
	}

	/**
	* Returns whether the content pane should get focus initially when in dual-pane configuration.
	*/
	protected boolean shouldFocusContentOnLaunch() {
	return true;
	}

	private void launchIfDifferent(Fragment newFragment) {
	Fragment currentFragment = getCurrentFragment();
	if ((newFragment != null) && differentFragment(newFragment, currentFragment)) {
	LOG.d("launchIfDifferent: " + newFragment + " replacing " + currentFragment);
	launchFragmentInternal(newFragment);
	}
	}

	/**
	* Returns {code true} if newFragment is different from current fragment.
	*/
	private boolean differentFragment(Fragment newFragment, Fragment currentFragment) {
	return (currentFragment == null)
	\|\| (!currentFragment.getClass().equals(newFragment.getClass()));
	}

	private void hideKeyboard() {
	InputMethodManager imm = (InputMethodManager) this.getSystemService(
	Context.INPUT_METHOD_SERVICE);
	imm.hideSoftInputFromWindow(getWindow().getDecorView().getWindowToken(), 0);
	}

	private void updateBlockingView(@Nullable Fragment currentFragment) {
	if (mRestrictedMessage == null) {
	return;
	}
	if (currentFragment instanceof BaseFragment
	&& !((BaseFragment) currentFragment).canBeShown(mCarUxRestrictions)) {
	mRestrictedMessage.setVisibility(View.VISIBLE);
	mFragmentContainer.setDescendantFocusability(FOCUS_BLOCK_DESCENDANTS);
	mFragmentContainer.clearFocus();
	hideKeyboard();
	} else {
	mRestrictedMessage.setVisibility(View.GONE);
	mFragmentContainer.setDescendantFocusability(FOCUS_BEFORE_DESCENDANTS);
	}
	}

	private void populateMetaData() {
	try {
	ActivityInfo ai = getPackageManager().getActivityInfo(getComponentName(),
	PackageManager.GET_META_DATA);
	if (ai == null \|\| ai.metaData == null) {
	mIsSinglePane = getResources().getBoolean(R.bool.config_global_force_single_pane);
	return;
	}
	mTopLevelHeaderKey = ai.metaData.getString(META_DATA_KEY_HEADER_KEY);
	mIsSinglePane = ai.metaData.getBoolean(META_DATA_KEY_SINGLE_PANE,
	getResources().getBoolean(R.bool.config_global_force_single_pane));
	} catch (PackageManager.NameNotFoundException e) {
	LOG.w("Unable to find package", e);
	}
	}

	private void setUpToolbars() {
	View globalToolbarWrappedView = mIsSinglePane ? findViewById(
	R.id.fragment_container_wrapper) : findViewById(R.id.top_level_menu_container);
	mGlobalToolbar = CarUi.installBaseLayoutAround(
	globalToolbarWrappedView,
	insets -> globalToolbarWrappedView.setPadding(
	insets.getLeft(), insets.getTop(), insets.getRight(),
	insets.getBottom()), /* hasToolbar= */ true);
	if (mIsSinglePane) {
	mGlobalToolbar.setNavButtonMode(NavButtonMode.BACK);
	findViewById(R.id.top_level_menu_container).setVisibility(View.GONE);
	findViewById(R.id.top_level_divider).setVisibility(View.GONE);
	return;
	}
	mMiniToolbar = CarUi.installBaseLayoutAround(
	findViewById(R.id.fragment_container_wrapper),
	insets -> findViewById(R.id.fragment_container_wrapper).setPadding(
	insets.getLeft(), insets.getTop(), insets.getRight(),
	insets.getBottom()), /* hasToolbar= */ true);

	MenuItem searchButton = new MenuItem.Builder(this)
	.setToSearch()
	.setOnClickListener(i -> onSearchButtonClicked())
	.setUxRestrictions(CarUxRestrictions.UX_RESTRICTIONS_NO_KEYBOARD)
	.setId(R.id.toolbar_menu_item_0)
	.build();
	List<MenuItem> items = Collections.singletonList(searchButton);

	mGlobalToolbar.setTitle(R.string.settings_label);
	mGlobalToolbar.setNavButtonMode(NavButtonMode.DISABLED);
	mGlobalToolbar.setLogo(R.drawable.ic_launcher_settings);
	mGlobalToolbar.setMenuItems(items);
	}

	private void updateMiniToolbarState() {
	if (mMiniToolbar == null) {
	return;
	}
	if (getSupportFragmentManager().getBackStackEntryCount() > 1 \|\| !isTaskRoot()) {
	mMiniToolbar.setNavButtonMode(NavButtonMode.BACK);
	} else {
	mMiniToolbar.setNavButtonMode(NavButtonMode.DISABLED);
	}
	}

	private void setUpFocusChangeListener(boolean enable) {
	if (mIsSinglePane) {
	// The focus change listener is only needed with two panes.
	return;
	}
	ViewTreeObserver observer = findViewById(
	R.id.car_settings_activity_wrapper).getViewTreeObserver();
	if (enable) {
	observer.addOnGlobalFocusChangeListener(mFocusChangeListener);
	} else {
	observer.removeOnGlobalFocusChangeListener(mFocusChangeListener);
	}
	}

	private void requestTopLevelMenuFocus() {
	if (mIsSinglePane) {
	return;
	}
	Fragment topLevelMenu = getSupportFragmentManager().findFragmentById(R.id.top_level_menu);
	if (topLevelMenu == null) {
	return;
	}
	View fragmentView = topLevelMenu.getView();
	if (fragmentView == null) {
	return;
	}
	View focusArea = fragmentView.findViewById(R.id.settings_car_ui_focus_area);
	if (focusArea == null) {
	return;
	}
	removeGlobalLayoutListener();
	mGlobalLayoutListener = () -> {
	if (focusArea.isInTouchMode() \|\| focusArea.hasFocus()) {
	return;
	}
	focusArea.performAccessibilityAction(ACTION_FOCUS, /* arguments= */ null);
	removeGlobalLayoutListener();
	};
	fragmentView.getViewTreeObserver().addOnGlobalLayoutListener(mGlobalLayoutListener);
	}

	private void requestContentPaneFocus() {
	if (mIsSinglePane) {
	return;
	}
	if (getCurrentFragment() == null) {
	return;
	}
	View fragmentView = getCurrentFragment().getView();
	if (fragmentView == null) {
	return;
	}
	removeGlobalLayoutListener();
	if (fragmentView.isInTouchMode()) {
	mHasInitialFocus = false;
	return;
	}
	View focusArea = fragmentView.findViewById(R.id.settings_car_ui_focus_area);

	if (focusArea == null) {
	focusArea = fragmentView.findViewById(R.id.settings_content_focus_area);
	if (focusArea == null) {
	return;
	}
	}
	removeGlobalLayoutListener();
	View finalFocusArea = focusArea; // required to be effectively final for inner class access
	mGlobalLayoutListener = () -> {
	if (finalFocusArea.isInTouchMode() \|\| finalFocusArea.hasFocus()) {
	return;
	}
	boolean success = finalFocusArea.performAccessibilityAction(
	ACTION_FOCUS, /* arguments= */ null);
	if (success) {
	removeGlobalLayoutListener();
	} else {
	findViewById(
	R.id.settings_focus_parking_view).performAccessibilityAction(
	ACTION_FOCUS, /* arguments= */ null);
	}
	};
	fragmentView.getViewTreeObserver().addOnGlobalLayoutListener(mGlobalLayoutListener);
	}

	private boolean shouldFocusContentOnBackstackChange() {
	// We don't want to reset mHasInitialFocus when initial fragment is added
	if (mIsInitialFragmentTransaction && getInitialFragment() != null) {
	mIsInitialFragmentTransaction = false;
	return false;
	}

	return true;
	}

	private void removeGlobalLayoutListener() {
	if (mGlobalLayoutListener == null) {
	return;
	}

	// Check content pane
	Fragment contentFragment = getCurrentFragment();
	if (contentFragment != null && contentFragment.getView() != null) {
	contentFragment.getView().getViewTreeObserver()
	.removeOnGlobalLayoutListener(mGlobalLayoutListener);
	}

	// Check top level menu
	Fragment topLevelMenu = getSupportFragmentManager().findFragmentById(R.id.top_level_menu);
	if (topLevelMenu != null && topLevelMenu.getView() != null) {
	topLevelMenu.getView().getViewTreeObserver()
	.removeOnGlobalLayoutListener(mGlobalLayoutListener);
	}

	mGlobalLayoutListener = null;
	}

	private void onSearchButtonClicked() {
	Intent intent = new Intent(Settings.ACTION_APP_SEARCH_SETTINGS)
	.setPackage(getSettingsIntelligencePkgName());
	if (intent.resolveActivity(getPackageManager()) == null) {
	return;
	}
	startActivityForResult(intent, SEARCH_REQUEST_CODE);
	}

	private String getSettingsIntelligencePkgName() {
	return getString(R.string.config_settingsintelligence_package_name);
	}
	}