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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package androidx.wear.internal.widget.drawer;
     18 
     19 import androidx.annotation.Nullable;
     20 import androidx.annotation.RestrictTo;
     21 import androidx.annotation.RestrictTo.Scope;
     22 import androidx.wear.widget.drawer.WearableNavigationDrawerView;
     23 import androidx.wear.widget.drawer.WearableNavigationDrawerView.WearableNavigationDrawerAdapter;
     24 
     25 /**
     26  * Provides a {@link WearableNavigationDrawerPresenter} implementation that is designed for the
     27  * multi-page navigation drawer.
     28  *
     29  * @hide
     30  */
     31 @RestrictTo(Scope.LIBRARY)
     32 public class MultiPagePresenter extends WearableNavigationDrawerPresenter {
     33 
     34     private final Ui mUi;
     35     private final WearableNavigationDrawerView mDrawer;
     36     private final boolean mIsAccessibilityEnabled;
     37     @Nullable private WearableNavigationDrawerAdapter mAdapter;
     38 
     39     /**
     40      * Controls the user interface of a multi-page {@link WearableNavigationDrawerView}.
     41      */
     42     public interface Ui {
     43 
     44         /**
     45          * Initializes the {@code Ui}.
     46          */
     47         void initialize(WearableNavigationDrawerView drawer,
     48                 WearableNavigationDrawerPresenter presenter);
     49 
     50         /**
     51          * Should notify the {@code NavigationPagerAdapter} that the underlying data has changed.
     52          */
     53         void notifyNavigationPagerAdapterDataChanged();
     54 
     55         /**
     56          * Should notify the Page Indicator that the underlying data has changed.
     57          */
     58         void notifyPageIndicatorDataChanged();
     59 
     60         /**
     61          * Associates the given {@code adapter} with this {@link Ui}.
     62          */
     63         void setNavigationPagerAdapter(WearableNavigationDrawerAdapter adapter);
     64 
     65         /**
     66          * Sets which item is selected and optionally smooth scrolls to it.
     67          */
     68         void setNavigationPagerSelectedItem(int index, boolean smoothScrollTo);
     69     }
     70 
     71     public MultiPagePresenter(WearableNavigationDrawerView drawer, Ui ui,
     72             boolean isAccessibilityEnabled) {
     73         if (drawer == null) {
     74             throw new IllegalArgumentException("Received null drawer.");
     75         }
     76         if (ui == null) {
     77             throw new IllegalArgumentException("Received null ui.");
     78         }
     79         mDrawer = drawer;
     80         mUi = ui;
     81         mUi.initialize(drawer, this);
     82         mIsAccessibilityEnabled = isAccessibilityEnabled;
     83     }
     84 
     85     @Override
     86     public void onDataSetChanged() {
     87         mUi.notifyNavigationPagerAdapterDataChanged();
     88         mUi.notifyPageIndicatorDataChanged();
     89     }
     90 
     91     @Override
     92     public void onNewAdapter(WearableNavigationDrawerAdapter adapter) {
     93         if (adapter == null) {
     94             throw new IllegalArgumentException("Received null adapter.");
     95         }
     96         mAdapter = adapter;
     97         mAdapter.setPresenter(this);
     98         mUi.setNavigationPagerAdapter(adapter);
     99     }
    100 
    101     @Override
    102     public void onSelected(int index) {
    103         notifyItemSelectedListeners(index);
    104     }
    105 
    106     @Override
    107     public void onSetCurrentItemRequested(int index, boolean smoothScrollTo) {
    108         mUi.setNavigationPagerSelectedItem(index, smoothScrollTo);
    109     }
    110 
    111     @Override
    112     public boolean onDrawerTapped() {
    113         if (mDrawer.isOpened()) {
    114             if (mIsAccessibilityEnabled) {
    115                 // When accessibility gestures are enabled, the user can't access a closed nav
    116                 // drawer, so peek it instead.
    117                 mDrawer.getController().peekDrawer();
    118             } else {
    119                 mDrawer.getController().closeDrawer();
    120             }
    121             return true;
    122         }
    123         return false;
    124     }
    125 }
    126