Java tutorial
/* * Copyright (C) 2016 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.adam.navigation; import android.content.Context; import android.content.res.ColorStateList; import android.os.Build; import android.os.Bundle; import android.os.Parcel; import android.os.Parcelable; import android.support.annotation.DrawableRes; import android.support.annotation.IdRes; import android.support.annotation.NonNull; import android.support.annotation.Nullable; import android.support.design.internal.BottomNavigationMenu; import android.support.v4.content.ContextCompat; import android.support.v4.os.ParcelableCompat; import android.support.v4.os.ParcelableCompatCreatorCallbacks; import android.support.v4.view.AbsSavedState; import android.support.v4.view.ViewCompat; import android.support.v7.content.res.AppCompatResources; import android.support.v7.view.SupportMenuInflater; import android.support.v7.view.menu.MenuBuilder; import android.support.v7.widget.TintTypedArray; import android.util.AttributeSet; import android.util.TypedValue; import android.view.Gravity; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.widget.FrameLayout; /** * <p> * Represents a standard bottom navigation bar for application. It is an implementation of * <a href="https://material.google.com/components/bottom-navigation.html">material design bottom * navigation</a>. * </p> * * <p> * Bottom navigation bars make it easy for users to explore and switch between top-level views in * a single tap. It should be used when application has three to five top-level destinations. * </p> * * <p> * The bar contents can be populated by specifying a menu resource file. Each menu item title, icon * and enabled state will be used for displaying bottom navigation bar items. Menu items can also be * used for programmatically selecting which destination is currently active. It can be done using * {@code MenuItem#setChecked(true)} * </p> * * <pre> * layout resource file: * <android.support.design.widget.BottomNavigationView * xmlns:android="http://schemas.android.com/apk/res/android" * xmlns:app="http://schemas.android.com/apk/res-auto" * android:id="@+id/navigation" * android:layout_width="match_parent" * android:layout_height="56dp" * android:layout_gravity="start" * app:menu="@menu/my_navigation_items" /> * * res/menu/my_navigation_items.xml: * <menu xmlns:android="http://schemas.android.com/apk/res/android"> * <item android:id="@+id/action_search" * android:title="@string/menu_search" * android:icon="@drawable/ic_search" /> * <item android:id="@+id/action_settings" * android:title="@string/menu_settings" * android:icon="@drawable/ic_add" /> * <item android:id="@+id/action_navigation" * android:title="@string/menu_navigation" * android:icon="@drawable/ic_action_navigation_menu" /> * </menu> * </pre> */ public class BottomNavigationViewNew extends FrameLayout { private static final int[] CHECKED_STATE_SET = { android.R.attr.state_checked }; private static final int[] DISABLED_STATE_SET = { -android.R.attr.state_enabled }; private static final int MENU_PRESENTER_ID = 1; private final MenuBuilder mMenu; private final BottomNavigationMenuView mMenuView; private final BottomNavigationPresenter mPresenter = new BottomNavigationPresenter(); private MenuInflater mMenuInflater; private OnNavigationItemSelectedListener mSelectedListener; private OnNavigationItemReselectedListener mReselectedListener; public BottomNavigationViewNew(Context context) { this(context, null); } public BottomNavigationViewNew(Context context, AttributeSet attrs) { this(context, attrs, 0); } public BottomNavigationViewNew(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); ThemeUtils.checkAppCompatTheme(context); // Create the menu mMenu = new BottomNavigationMenu(context); mMenuView = new BottomNavigationMenuView(context); LayoutParams params = new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT); params.gravity = Gravity.CENTER; mMenuView.setLayoutParams(params); mPresenter.setBottomNavigationMenuView(mMenuView); mPresenter.setId(MENU_PRESENTER_ID); mMenuView.setPresenter(mPresenter); mMenu.addMenuPresenter(mPresenter); mPresenter.initForMenu(getContext(), mMenu); // Custom attributes TintTypedArray a = TintTypedArray.obtainStyledAttributes(context, attrs, android.support.design.R.styleable.BottomNavigationView, defStyleAttr, android.support.design.R.style.Widget_Design_BottomNavigationView); if (a.hasValue(android.support.design.R.styleable.BottomNavigationView_itemIconTint)) { mMenuView.setIconTintList( a.getColorStateList(android.support.design.R.styleable.BottomNavigationView_itemIconTint)); } else { mMenuView.setIconTintList(createDefaultColorStateList(android.R.attr.textColorSecondary)); } if (a.hasValue(android.support.design.R.styleable.BottomNavigationView_itemTextColor)) { mMenuView.setItemTextColor( a.getColorStateList(android.support.design.R.styleable.BottomNavigationView_itemTextColor)); } else { mMenuView.setItemTextColor(createDefaultColorStateList(android.R.attr.textColorSecondary)); } if (a.hasValue(android.support.design.R.styleable.BottomNavigationView_elevation)) { ViewCompat.setElevation(this, a.getDimensionPixelSize(android.support.design.R.styleable.BottomNavigationView_elevation, 0)); } int itemBackground = a.getResourceId(android.support.design.R.styleable.BottomNavigationView_itemBackground, 0); mMenuView.setItemBackgroundRes(itemBackground); if (a.hasValue(android.support.design.R.styleable.BottomNavigationView_menu)) { inflateMenu(a.getResourceId(android.support.design.R.styleable.BottomNavigationView_menu, 0)); } a.recycle(); addView(mMenuView, params); if (Build.VERSION.SDK_INT < 21) { addCompatibilityTopDivider(context); } mMenu.setCallback(new MenuBuilder.Callback() { @Override public boolean onMenuItemSelected(MenuBuilder menu, MenuItem item) { if (mReselectedListener != null && item.getItemId() == getSelectedItemId()) { mReselectedListener.onNavigationItemReselected(item); return true; // item is already selected } return mSelectedListener != null && !mSelectedListener.onNavigationItemSelected(item); } @Override public void onMenuModeChange(MenuBuilder menu) { } }); } /** * Set a listener that will be notified when a bottom navigation item is selected. This listener * will also be notified when the currently selected item is reselected, unless an * {@link OnNavigationItemReselectedListener} has also been set. * * @param listener The listener to notify * * @see #setOnNavigationItemReselectedListener(OnNavigationItemReselectedListener) */ public void setOnNavigationItemSelectedListener(@Nullable OnNavigationItemSelectedListener listener) { mSelectedListener = listener; } /** * Set a listener that will be notified when the currently selected bottom navigation item is * reselected. This does not require an {@link OnNavigationItemSelectedListener} to be set. * * @param listener The listener to notify * * @see #setOnNavigationItemSelectedListener(OnNavigationItemSelectedListener) */ public void setOnNavigationItemReselectedListener(@Nullable OnNavigationItemReselectedListener listener) { mReselectedListener = listener; } /** * Returns the {@link Menu} instance associated with this bottom navigation bar. */ @NonNull public Menu getMenu() { return mMenu; } /** * Inflate a menu resource into this navigation view. * * <p>Existing items in the menu will not be modified or removed.</p> * * @param resId ID of a menu resource to inflate */ public void inflateMenu(int resId) { mPresenter.setUpdateSuspended(true); getMenuInflater().inflate(resId, mMenu); mPresenter.setUpdateSuspended(false); mPresenter.updateMenuView(true); } /** * @return The maximum number of items that can be shown in BottomNavigationView. */ public int getMaxItemCount() { return BottomNavigationMenu.MAX_ITEM_COUNT; } /** * Returns the tint which is applied to our menu items' icons. * * @see #setItemIconTintList(ColorStateList) * * @attr ref R.styleable#BottomNavigationView_itemIconTint */ @Nullable public ColorStateList getItemIconTintList() { return mMenuView.getIconTintList(); } /** * Set the tint which is applied to our menu items' icons. * * @param tint the tint to apply. * * @attr ref R.styleable#BottomNavigationView_itemIconTint */ public void setItemIconTintList(@Nullable ColorStateList tint) { mMenuView.setIconTintList(tint); } /** * Returns colors used for the different states (normal, selected, focused, etc.) of the menu * item text. * * @see #setItemTextColor(ColorStateList) * * @return the ColorStateList of colors used for the different states of the menu items text. * * @attr ref R.styleable#BottomNavigationView_itemTextColor */ @Nullable public ColorStateList getItemTextColor() { return mMenuView.getItemTextColor(); } /** * Set the colors to use for the different states (normal, selected, focused, etc.) of the menu * item text. * * @see #getItemTextColor() * * @attr ref R.styleable#BottomNavigationView_itemTextColor */ public void setItemTextColor(@Nullable ColorStateList textColor) { mMenuView.setItemTextColor(textColor); } /** * Returns the background resource of the menu items. * * @see #setItemBackgroundResource(int) * * @attr ref R.styleable#BottomNavigationView_itemBackground */ @DrawableRes public int getItemBackgroundResource() { return mMenuView.getItemBackgroundRes(); } /** * Set the background of our menu items to the given resource. * * @param resId The identifier of the resource. * * @attr ref R.styleable#BottomNavigationView_itemBackground */ public void setItemBackgroundResource(@DrawableRes int resId) { mMenuView.setItemBackgroundRes(resId); } /** * Returns the currently selected menu item ID, or zero if there is no menu. * * @see #setSelectedItemId(int) */ @IdRes public int getSelectedItemId() { return mMenuView.getSelectedItemId(); } /** * Set the selected menu item ID. This behaves the same as tapping on an item. * * @param itemId The menu item ID. If no item has this ID, the current selection is unchanged. * * @see #getSelectedItemId() */ public void setSelectedItemId(@IdRes int itemId) { MenuItem item = mMenu.findItem(itemId); if (item != null) { if (!mMenu.performItemAction(item, mPresenter, 0)) { item.setChecked(true); } } } /** * Listener for handling selection events on bottom navigation items. */ public interface OnNavigationItemSelectedListener { /** * Called when an item in the bottom navigation menu is selected. * * @param item The selected item * * @return true to display the item as the selected item and false if the item should not * be selected. Consider setting non-selectable items as disabled preemptively to * make them appear non-interactive. */ boolean onNavigationItemSelected(@NonNull MenuItem item); } /** * Listener for handling reselection events on bottom navigation items. */ public interface OnNavigationItemReselectedListener { /** * Called when the currently selected item in the bottom navigation menu is selected again. * * @param item The selected item */ void onNavigationItemReselected(@NonNull MenuItem item); } private void addCompatibilityTopDivider(Context context) { View divider = new View(context); divider.setBackgroundColor(ContextCompat.getColor(context, android.support.design.R.color.design_bottom_navigation_shadow_color)); LayoutParams dividerParams = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, getResources() .getDimensionPixelSize(android.support.design.R.dimen.design_bottom_navigation_shadow_height)); divider.setLayoutParams(dividerParams); addView(divider); } private MenuInflater getMenuInflater() { if (mMenuInflater == null) { mMenuInflater = new SupportMenuInflater(getContext()); } return mMenuInflater; } private ColorStateList createDefaultColorStateList(int baseColorThemeAttr) { final TypedValue value = new TypedValue(); if (!getContext().getTheme().resolveAttribute(baseColorThemeAttr, value, true)) { return null; } ColorStateList baseColor = AppCompatResources.getColorStateList(getContext(), value.resourceId); if (!getContext().getTheme().resolveAttribute(android.support.v7.appcompat.R.attr.colorPrimary, value, true)) { return null; } int colorPrimary = value.data; int defaultColor = baseColor.getDefaultColor(); return new ColorStateList(new int[][] { DISABLED_STATE_SET, CHECKED_STATE_SET, EMPTY_STATE_SET }, new int[] { baseColor.getColorForState(DISABLED_STATE_SET, defaultColor), colorPrimary, defaultColor }); } @Override protected Parcelable onSaveInstanceState() { Parcelable superState = super.onSaveInstanceState(); SavedState savedState = new SavedState(superState); savedState.menuPresenterState = new Bundle(); mMenu.savePresenterStates(savedState.menuPresenterState); return savedState; } @Override protected void onRestoreInstanceState(Parcelable state) { if (!(state instanceof SavedState)) { super.onRestoreInstanceState(state); return; } SavedState savedState = (SavedState) state; super.onRestoreInstanceState(savedState.getSuperState()); mMenu.restorePresenterStates(savedState.menuPresenterState); } static class SavedState extends AbsSavedState { Bundle menuPresenterState; public SavedState(Parcelable superState) { super(superState); } public SavedState(Parcel source, ClassLoader loader) { super(source, loader); readFromParcel(source, loader); } @Override public void writeToParcel(@NonNull Parcel out, int flags) { super.writeToParcel(out, flags); out.writeBundle(menuPresenterState); } private void readFromParcel(Parcel in, ClassLoader loader) { menuPresenterState = in.readBundle(loader); } public static final Creator<SavedState> CREATOR = ParcelableCompat .newCreator(new ParcelableCompatCreatorCallbacks<SavedState>() { @Override public SavedState createFromParcel(Parcel in, ClassLoader loader) { return new SavedState(in, loader); } @Override public SavedState[] newArray(int size) { return new SavedState[size]; } }); } }