Java tutorial
/* * 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.navigation.ui; import android.animation.ObjectAnimator; import android.animation.ValueAnimator; import android.support.annotation.IdRes; import android.support.annotation.NonNull; import android.support.annotation.Nullable; import android.support.design.widget.BottomNavigationView; import android.support.design.widget.NavigationView; import android.support.v4.view.GravityCompat; import android.support.v4.widget.DrawerLayout; import android.support.v7.app.ActionBar; import android.support.v7.app.ActionBarDrawerToggle; import android.support.v7.app.AppCompatActivity; import android.support.v7.graphics.drawable.DrawerArrowDrawable; import android.text.TextUtils; import android.view.Menu; import android.view.MenuItem; import android.view.ViewParent; import androidx.navigation.NavController; import androidx.navigation.NavDestination; import androidx.navigation.NavGraph; import androidx.navigation.NavOptions; /** * Class which hooks up elements typically in the 'chrome' of your application such as global * navigation patterns like a navigation drawer or bottom nav bar with your {@link NavController}. */ public class NavigationUI { // No instances. Static utilities only. private NavigationUI() { } /** * Attempt to navigate to the {@link NavDestination} associated with the given MenuItem. This * MenuItem should have been added via one of the helper methods in this class. * * <p>Importantly, it assumes the {@link MenuItem#getItemId() menu item id} matches a valid * {@link NavDestination#getAction(int) action id} or * {@link NavDestination#getId() destination id} to be navigated to.</p> * * @param item The selected MenuItem. * @param navController The NavController that hosts the destination. * @return True if the {@link NavController} was able to navigate to the destination * associated with the given MenuItem. */ public static boolean onNavDestinationSelected(@NonNull MenuItem item, @NonNull NavController navController) { return onNavDestinationSelected(item, navController, false); } private static boolean onNavDestinationSelected(@NonNull MenuItem item, @NonNull NavController navController, boolean popUp) { NavOptions.Builder builder = new NavOptions.Builder().setLaunchSingleTop(true) .setEnterAnim(R.anim.nav_default_enter_anim).setExitAnim(R.anim.nav_default_exit_anim) .setPopEnterAnim(R.anim.nav_default_pop_enter_anim) .setPopExitAnim(R.anim.nav_default_pop_exit_anim); if (popUp) { builder.setPopUpTo(findStartDestination(navController.getGraph()).getId(), false); } NavOptions options = builder.build(); try { //TODO provide proper API instead of using Exceptions as Control-Flow. navController.navigate(item.getItemId(), null, options); return true; } catch (IllegalArgumentException e) { return false; } } /** * Handles the Up button by delegating its behavior to the given NavController. This should * generally be called from {@link AppCompatActivity#onSupportNavigateUp()}. * <p>If you do not have a {@link DrawerLayout}, you should call * {@link NavController#navigateUp()} directly. * * @param drawerLayout The DrawerLayout that should be opened if you are on the topmost level * of the app. * @param navController The NavController that hosts your content. * @return True if the {@link NavController} was able to navigate up. */ public static boolean navigateUp(@Nullable DrawerLayout drawerLayout, @NonNull NavController navController) { if (drawerLayout != null && navController.getCurrentDestination() == findStartDestination(navController.getGraph())) { drawerLayout.openDrawer(GravityCompat.START); return true; } else { return navController.navigateUp(); } } /** * Sets up the ActionBar returned by {@link AppCompatActivity#getSupportActionBar()} for use * with a {@link NavController}. * * <p>By calling this method, the title in the action bar will automatically be updated when * the destination changes (assuming there is a valid {@link NavDestination#getLabel label}). * * <p>The action bar will also display the Up button when you are on a non-root destination. * Call {@link #navigateUp(DrawerLayout, NavController)} to handle the Up button. * * @param activity The activity hosting the action bar that should be kept in sync with changes * to the NavController. * @param navController The NavController that supplies the secondary menu. Navigation actions * on this NavController will be reflected in the title of the action bar. */ public static void setupActionBarWithNavController(@NonNull AppCompatActivity activity, @NonNull NavController navController) { setupActionBarWithNavController(activity, navController, null); } /** * Sets up the ActionBar returned by {@link AppCompatActivity#getSupportActionBar()} for use * with a {@link NavController}. * * <p>By calling this method, the title in the action bar will automatically be updated when * the destination changes (assuming there is a valid {@link NavDestination#getLabel label}). * * <p>The action bar will also display the Up button when you are on a non-root destination and * the drawer icon when on the root destination, automatically animating between them. * Call {@link #navigateUp(DrawerLayout, NavController)} to handle the Up button. * @param activity The activity hosting the action bar that should be kept in sync with changes * to the NavController. * @param navController The NavController whose navigation actions will be reflected * in the title of the action bar. * @param drawerLayout The DrawerLayout that should be toggled from the home button */ public static void setupActionBarWithNavController(@NonNull AppCompatActivity activity, @NonNull NavController navController, @Nullable DrawerLayout drawerLayout) { navController.addOnNavigatedListener(new ActionBarOnNavigatedListener(activity, drawerLayout)); } /** * Sets up a {@link NavigationView} for use with a {@link NavController}. This will call * {@link #onNavDestinationSelected(MenuItem, NavController)} when a menu item is selected. * The selected item in the NavigationView will automatically be updated when the destination * changes. * * @param navigationView The NavigationView that should be kept in sync with changes to the * NavController. * @param navController The NavController that supplies the primary and secondary menu. * Navigation actions on this NavController will be reflected in the * selected item in the NavigationView. */ public static void setupWithNavController(@NonNull final NavigationView navigationView, @NonNull final NavController navController) { navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() { @Override public boolean onNavigationItemSelected(@NonNull MenuItem item) { boolean handled = onNavDestinationSelected(item, navController, true); if (handled) { ViewParent parent = navigationView.getParent(); if (parent instanceof DrawerLayout) { ((DrawerLayout) parent).closeDrawer(navigationView); } } return handled; } }); navController.addOnNavigatedListener(new NavController.OnNavigatedListener() { @Override public void onNavigated(@NonNull NavController controller, @NonNull NavDestination destination) { Menu menu = navigationView.getMenu(); for (int h = 0, size = menu.size(); h < size; h++) { MenuItem item = menu.getItem(h); item.setChecked(matchDestination(destination, item.getItemId())); } } }); } /** * Sets up a {@link BottomNavigationView} for use with a {@link NavController}. This will call * {@link #onNavDestinationSelected(MenuItem, NavController)} when a menu item is selected. The * selected item in the BottomNavigationView will automatically be updated when the destination * changes. * * @param bottomNavigationView The BottomNavigationView that should be kept in sync with * changes to the NavController. * @param navController The NavController that supplies the primary menu. * Navigation actions on this NavController will be reflected in the * selected item in the BottomNavigationView. */ public static void setupWithNavController(@NonNull final BottomNavigationView bottomNavigationView, @NonNull final NavController navController) { bottomNavigationView .setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() { @Override public boolean onNavigationItemSelected(@NonNull MenuItem item) { return onNavDestinationSelected(item, navController, true); } }); navController.addOnNavigatedListener(new NavController.OnNavigatedListener() { @Override public void onNavigated(@NonNull NavController controller, @NonNull NavDestination destination) { Menu menu = bottomNavigationView.getMenu(); for (int h = 0, size = menu.size(); h < size; h++) { MenuItem item = menu.getItem(h); if (matchDestination(destination, item.getItemId())) { item.setChecked(true); } } } }); } /** * Determines whether the given <code>destId</code> matches the NavDestination. This handles * both the default case (the destination's id matches the given id) and the nested case where * the given id is a parent/grandparent/etc of the destination. */ private static boolean matchDestination(@NonNull NavDestination destination, @IdRes int destId) { NavDestination currentDestination = destination; while (currentDestination.getId() != destId && currentDestination.getParent() != null) { currentDestination = currentDestination.getParent(); } return currentDestination.getId() == destId; } /** * Finds the actual start destination of the graph, handling cases where the graph's starting * destination is itself a NavGraph. */ private static NavDestination findStartDestination(@NonNull NavGraph graph) { NavDestination startDestination = graph; while (startDestination instanceof NavGraph) { NavGraph parent = (NavGraph) startDestination; startDestination = parent.findNode(parent.getStartDestination()); } return startDestination; } /** * The OnNavigatedListener specifically for keeping the ActionBar updated. This handles both * updating the title and updating the Up Indicator transitioning between the */ private static class ActionBarOnNavigatedListener implements NavController.OnNavigatedListener { private final AppCompatActivity mActivity; @Nullable private final DrawerLayout mDrawerLayout; private DrawerArrowDrawable mArrowDrawable; private ValueAnimator mAnimator; ActionBarOnNavigatedListener(@NonNull AppCompatActivity activity, @Nullable DrawerLayout drawerLayout) { mActivity = activity; mDrawerLayout = drawerLayout; } @Override public void onNavigated(@NonNull NavController controller, @NonNull NavDestination destination) { ActionBar actionBar = mActivity.getSupportActionBar(); CharSequence title = destination.getLabel(); if (!TextUtils.isEmpty(title)) { actionBar.setTitle(title); } boolean isStartDestination = findStartDestination(controller.getGraph()) == destination; actionBar.setDisplayHomeAsUpEnabled(mDrawerLayout != null || !isStartDestination); setActionBarUpIndicator(mDrawerLayout != null && isStartDestination); } void setActionBarUpIndicator(boolean showAsDrawerIndicator) { ActionBarDrawerToggle.Delegate delegate = mActivity.getDrawerToggleDelegate(); boolean animate = true; if (mArrowDrawable == null) { mArrowDrawable = new DrawerArrowDrawable(delegate.getActionBarThemedContext()); delegate.setActionBarUpIndicator(mArrowDrawable, 0); // We're setting the initial state, so skip the animation animate = false; } float endValue = showAsDrawerIndicator ? 0f : 1f; if (animate) { float startValue = mArrowDrawable.getProgress(); if (mAnimator != null) { mAnimator.cancel(); } mAnimator = ObjectAnimator.ofFloat(mArrowDrawable, "progress", startValue, endValue); mAnimator.start(); } else { mArrowDrawable.setProgress(endValue); } } } }