CarDrawerController.java
/*
* Copyright (C) 2017 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 androidx.car.drawer;
import android.content.Context;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.os.Bundle;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.MenuItem;
import android.view.View;
import android.view.animation.AnimationUtils;
import android.widget.ProgressBar;
import android.widget.TextView;
import androidx.annotation.AnimRes;
import androidx.annotation.IdRes;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.ActionBarDrawerToggle;
import androidx.car.R;
import androidx.car.util.DropShadowScrollListener;
import androidx.car.widget.PagedListView;
import androidx.drawerlayout.widget.DrawerLayout;
import androidx.recyclerview.widget.RecyclerView;
import java.util.ArrayDeque;
/**
* A controller that will handle the set up of the navigation drawer. It will hook up the
* necessary buttons for up navigation, as well as expose methods to allow for a drill down
* navigation.
*/
public class CarDrawerController {
/** An animation for when a user navigates into a submenu. */
@AnimRes
private static final int DRILL_DOWN_ANIM = R.anim.fade_in_trans_right_layout_anim;
/** An animation for when a user navigates up (when the back button is pressed). */
@AnimRes
private static final int NAVIGATE_UP_ANIM = R.anim.fade_in_trans_left_layout_anim;
/**
* A representation of the hierarchy of navigation being displayed in the list. The ordering of
* this stack is the order that the user has visited each level. When the user navigates up,
* the adapters are popped from this list.
*/
private final ArrayDeque<CarDrawerAdapter> mAdapterStack = new ArrayDeque<>();
private final Context mContext;
private final TextView mTitleView;
private final DrawerLayout mDrawerLayout;
private final ActionBarDrawerToggle mDrawerToggle;
private final PagedListView mDrawerList;
private final ProgressBar mProgressBar;
/**
* Creates a {@link CarDrawerController} that will control the navigation of the drawer given by
* {@code drawerLayout}.
*
* <p>The given {@code drawerLayout} should either have a child view that is inflated from
* {@code R.layout.car_drawer} or ensure that its child views have the IDs expected in that
* layout. The ids expected can be configured in the theme by {@code R.attr.drawerBackButtonId},
* {@code R.attr.drawerListId}, {@code R.attr.drawerTitleId} and
* {@code R.attr.drawerProgressId}.
*
* @param drawerLayout The top-level container for the window content that shows the
* interactive drawer.
* @param drawerToggle The {@link ActionBarDrawerToggle} that will open the drawer.
* {@link R.attr#drawerBackButtonId}
* {@link R.attr#drawerListId}
* {@link R.attr#drawerProgressId}
* {@link R.attr#drawerTitleId}
*/
public CarDrawerController(@NonNull DrawerLayout drawerLayout,
@NonNull ActionBarDrawerToggle drawerToggle) {
mContext = drawerLayout.getContext();
mDrawerToggle = drawerToggle;
mDrawerLayout = drawerLayout;
TypedValue outValue = new TypedValue();
Resources.Theme theme = mContext.getTheme();
mTitleView = drawerLayout.findViewById(
theme.resolveAttribute(R.attr.drawerTitleId, outValue, true)
? outValue.resourceId
: R.id.car_drawer_title);
mProgressBar = drawerLayout.findViewById(
theme.resolveAttribute(R.attr.drawerProgressId, outValue, true)
? outValue.resourceId
: R.id.car_drawer_progress);
mDrawerList = drawerLayout.findViewById(
theme.resolveAttribute(R.attr.drawerListId, outValue, true)
? outValue.resourceId
: R.id.car_drawer_list);
mDrawerList.setMaxPages(PagedListView.UNLIMITED_PAGES);
View toolbar = drawerLayout.findViewById(
theme.resolveAttribute(R.attr.drawerToolbarId, outValue, true)
? outValue.resourceId
: R.id.drawer_toolbar);
mDrawerList.setOnScrollListener(new DropShadowScrollListener(toolbar));
@IdRes int backButtonId = theme.resolveAttribute(R.attr.drawerBackButtonId, outValue, true)
? outValue.resourceId
: R.id.car_drawer_back_button;
drawerLayout.findViewById(backButtonId).setOnClickListener(v -> {
if (!maybeHandleUpClick()) {
closeDrawer();
}
});
setupDrawerToggling();
}
/**
* Sets the {@link CarDrawerAdapter} that will function as the root adapter. The contents of
* this root adapter are shown when the drawer is first opened. It is also the top-most level of
* navigation in the drawer.
*
* @param rootAdapter The adapter that will act as the root. If this value is {@code null}, then
* this method will do nothing.
*/
public void setRootAdapter(@Nullable CarDrawerAdapter rootAdapter) {
if (rootAdapter == null) {
return;
}
// The root adapter is always the last item in the stack.
if (!mAdapterStack.isEmpty()) {
mAdapterStack.removeLast();
}
mAdapterStack.addLast(rootAdapter);
setDisplayAdapter(rootAdapter);
}
/**
* Switches to use the given {@link CarDrawerAdapter} as the one to supply the list to display
* in the navigation drawer. The title will also be updated from the adapter.
*
* <p>This switch is treated as a navigation to the next level in the drawer. Navigation away
* from this level will pop the given adapter off and surface contents of the previous adapter
* that was set via this method. If no such adapter exists, then the root adapter set by
* {@link #setRootAdapter(CarDrawerAdapter)} will be used instead.
*
* @param adapter Adapter for next level of content in the drawer.
*/
public final void pushAdapter(CarDrawerAdapter adapter) {
mAdapterStack.peek().setTitleChangeListener(null);
mAdapterStack.push(adapter);
setDisplayAdapter(adapter);
runLayoutAnimation(DRILL_DOWN_ANIM);
}
/** Close the drawer. */
public void closeDrawer() {
if (mDrawerLayout.isDrawerOpen(Gravity.LEFT)) {
mDrawerLayout.closeDrawer(Gravity.LEFT);
}
}
/** Opens the drawer. */
public void openDrawer() {
if (!mDrawerLayout.isDrawerOpen(Gravity.LEFT)) {
mDrawerLayout.openDrawer(Gravity.LEFT);
}
}
/** Sets a listener to be notified of Drawer events. */
public void addDrawerListener(@NonNull DrawerLayout.DrawerListener listener) {
mDrawerLayout.addDrawerListener(listener);
}
/** Removes a listener to be notified of Drawer events. */
public void removeDrawerListener(@NonNull DrawerLayout.DrawerListener listener) {
mDrawerLayout.removeDrawerListener(listener);
}
/**
* Sets whether the loading progress bar is displayed in the navigation drawer. If {@code true},
* the progress bar is displayed and the navigation list is hidden and vice versa.
*/
public void showLoadingProgressBar(boolean show) {
mDrawerList.setVisibility(show ? View.INVISIBLE : View.VISIBLE);
mProgressBar.setVisibility(show ? View.VISIBLE : View.GONE);
}
/** Scroll to given position in the list. */
public void scrollToPosition(int position) {
mDrawerList.getRecyclerView().smoothScrollToPosition(position);
}
/**
* Retrieves the title from the given {@link CarDrawerAdapter} and set its as the title of this
* controller's internal Toolbar.
*/
private void setToolbarTitleFrom(CarDrawerAdapter adapter) {
mTitleView.setText(adapter.getTitle());
adapter.setTitleChangeListener(mTitleView::setText);
}
/**
* Sets up the necessary listeners for {@link DrawerLayout} so that the navigation drawer
* hierarchy is properly displayed.
*/
private void setupDrawerToggling() {
mDrawerLayout.addDrawerListener(mDrawerToggle);
mDrawerLayout.addDrawerListener(
new DrawerLayout.DrawerListener() {
@Override
public void onDrawerSlide(View drawerView, float slideOffset) {}
@Override
public void onDrawerClosed(View drawerView) {
// If drawer is closed, revert stack/drawer to initial root state.
cleanupStackAndShowRoot();
scrollToPosition(0);
}
@Override
public void onDrawerOpened(View drawerView) {}
@Override
public void onDrawerStateChanged(int newState) {}
});
}
/**
* Synchronizes the display of the drawer with its linked {@link DrawerLayout}.
*
* <p>This should be called from the associated Activity's
* {@link androidx.appcompat.app.AppCompatActivity#onPostCreate(Bundle)} method to synchronize
* after the DrawerLayout's instance state has been restored, and any other time when the
* state may have diverged in such a way that this controller's associated
* {@link ActionBarDrawerToggle} had not been notified.
*/
public void syncState() {
mDrawerToggle.syncState();
}
/**
* Notify this controller that device configurations may have changed.
*
* <p>This method should be called from the associated Activity's
* {@code onConfigurationChanged()} method.
*/
public void onConfigurationChanged(Configuration newConfig) {
// Pass any configuration change to the drawer toggle.
mDrawerToggle.onConfigurationChanged(newConfig);
}
/**
* Sets the given adapter as the one displaying the current contents of the drawer.
*
* <p>The drawer's title will also be derived from the given adapter.
*/
private void setDisplayAdapter(CarDrawerAdapter adapter) {
setToolbarTitleFrom(adapter);
// NOTE: We don't use swapAdapter() since different levels in the Drawer may switch between
// car_drawer_list_item_normal, car_drawer_list_item_small and car_list_empty layouts.
mDrawerList.getRecyclerView().setAdapter(adapter);
}
/**
* An analog to an Activity's {@code onOptionsItemSelected()}. This method should be called
* when the Activity's method is called and will return {@code true} if the selection has
* been handled.
*
* @return {@code true} if the item processing was handled by this class.
*/
public boolean onOptionsItemSelected(MenuItem item) {
// Handle home-click and see if we can navigate up in the drawer.
if (item != null && item.getItemId() == android.R.id.home && maybeHandleUpClick()) {
return true;
}
// DrawerToggle gets next chance to handle up-clicks (and any other clicks).
return mDrawerToggle.onOptionsItemSelected(item);
}
/**
* Switches to the previous level in the drawer hierarchy if the current list being displayed
* is not the root adapter. This is analogous to a navigate up.
*
* @return {@code true} if a navigate up was possible and executed. {@code false} otherwise.
*/
private boolean maybeHandleUpClick() {
// Check if already at the root level.
if (mAdapterStack.size() <= 1) {
return false;
}
CarDrawerAdapter adapter = mAdapterStack.pop();
adapter.setTitleChangeListener(null);
adapter.cleanup();
setDisplayAdapter(mAdapterStack.peek());
runLayoutAnimation(NAVIGATE_UP_ANIM);
return true;
}
/** Clears stack down to root adapter and switches to root adapter. */
@SuppressWarnings("WeakerAccess") /* synthetic access */
void cleanupStackAndShowRoot() {
while (mAdapterStack.size() > 1) {
CarDrawerAdapter adapter = mAdapterStack.pop();
adapter.setTitleChangeListener(null);
adapter.cleanup();
}
setDisplayAdapter(mAdapterStack.peek());
runLayoutAnimation(NAVIGATE_UP_ANIM);
}
/**
* Runs the given layout animation on the PagedListView. Running this animation will also
* refresh the contents of the list.
*/
private void runLayoutAnimation(@AnimRes int animation) {
RecyclerView recyclerView = mDrawerList.getRecyclerView();
recyclerView.setLayoutAnimation(AnimationUtils.loadLayoutAnimation(mContext, animation));
recyclerView.getAdapter().notifyDataSetChanged();
recyclerView.scheduleLayoutAnimation();
}
}