1/*
2 * Copyright (C) 2016 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
17package com.android.documentsui.dirlist;
18
19import static com.android.documentsui.base.Shared.VERBOSE;
20
21import android.annotation.Nullable;
22import android.content.Context;
23import android.os.Build;
24import android.support.v7.widget.RecyclerView;
25import android.support.v7.widget.RecyclerView.OnItemTouchListener;
26import android.util.Log;
27import android.view.GestureDetector;
28import android.view.MotionEvent;
29import android.view.ScaleGestureDetector;
30
31import com.android.documentsui.base.BooleanConsumer;
32import com.android.documentsui.base.EventHandler;
33import com.android.documentsui.base.Events;
34import com.android.documentsui.base.Events.InputEvent;
35import com.android.documentsui.base.Events.MotionInputEvent;
36import com.android.documentsui.base.Features;
37import com.android.documentsui.selection.BandController;
38import com.android.documentsui.selection.GestureSelector;
39
40import java.util.function.Consumer;
41
42//Receives event meant for both directory and empty view, and either pass them to
43//{@link UserInputHandler} for simple gestures (Single Tap, Long-Press), or intercept them for
44//other types of gestures (drag n' drop)
45final class ListeningGestureDetector extends GestureDetector implements OnItemTouchListener {
46
47    private static final String TAG = "ListeningGestureDetector";
48
49    private final Features mFeatures;
50    private final GestureSelector mGestureSelector;
51    private final EventHandler<InputEvent> mMouseDragListener;
52    private final BooleanConsumer mRefreshLayoutEnabler;
53    private final BandController mBandController;
54    private final MouseDelegate mMouseDelegate = new MouseDelegate();
55    private final TouchDelegate mTouchDelegate = new TouchDelegate();
56
57    // Currently only initialized on IS_DEBUGGABLE builds.
58    private final @Nullable ScaleGestureDetector mScaleDetector;
59
60    public ListeningGestureDetector(
61            Features features,
62            Context context,
63            RecyclerView recView,
64            EventHandler<InputEvent> mouseDragListener,
65            BooleanConsumer refreshLayoutEnabler,
66            GestureSelector gestureSelector,
67            UserInputHandler<? extends InputEvent> handler,
68            @Nullable BandController bandController,
69            Consumer<Float> scaleHandler) {
70
71        super(context, handler);
72
73        mFeatures = features;
74        mMouseDragListener = mouseDragListener;
75        mRefreshLayoutEnabler = refreshLayoutEnabler;
76        mGestureSelector = gestureSelector;
77        mBandController = bandController;
78        recView.addOnItemTouchListener(this);
79
80        mScaleDetector = !Build.IS_DEBUGGABLE
81                ? null
82                : new ScaleGestureDetector(
83                        context,
84                        new ScaleGestureDetector.SimpleOnScaleGestureListener() {
85                            @Override
86                            public boolean onScale(ScaleGestureDetector detector) {
87                                if (VERBOSE) Log.v(TAG,
88                                        "Received scale event: " + detector.getScaleFactor());
89                                scaleHandler.accept(detector.getScaleFactor());
90                                return true;
91                            }
92                        });
93    }
94
95    @Override
96    public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
97        boolean handled = false;
98
99        // TODO: Re-wire event handling so that we're not dispatching
100        //     events to to scaledetector's #onTouchEvent from this
101        //     #onInterceptTouchEvent touch event.
102        if (mFeatures.isGestureScaleEnabled()
103                && mScaleDetector != null) {
104            mScaleDetector.onTouchEvent(e);
105        }
106
107        try (InputEvent event = MotionInputEvent.obtain(e, rv)) {
108            if (event.isMouseEvent()) {
109                if (event.isActionDown()) {
110                    mRefreshLayoutEnabler.accept(false);
111                }
112                handled |= mMouseDelegate.onInterceptTouchEvent(event);
113            } else {
114                // If user has started some gesture while RecyclerView is not at the top, disable
115                // refresh
116                if (event.isActionDown() && rv.computeVerticalScrollOffset() != 0) {
117                    mRefreshLayoutEnabler.accept(false);
118                }
119                handled |= mTouchDelegate.onInterceptTouchEvent(event);
120            }
121
122
123            if (event.isActionUp()) {
124                mRefreshLayoutEnabler.accept(true);
125            }
126        }
127
128        // Forward all events to UserInputHandler.
129        // This is necessary since UserInputHandler needs to always see the first DOWN event. Or
130        // else all future UP events will be tossed.
131        handled |= onTouchEvent(e);
132
133        return handled;
134    }
135
136    @Override
137    public void onTouchEvent(RecyclerView rv, MotionEvent e) {
138        try (InputEvent event = MotionInputEvent.obtain(e, rv)) {
139            if (Events.isMouseEvent(e)) {
140                mMouseDelegate.onTouchEvent(event);
141            } else {
142                mTouchDelegate.onTouchEvent(rv, event);
143            }
144
145            if (event.isActionUp()) {
146                mRefreshLayoutEnabler.accept(true);
147            }
148        }
149
150        // Note: even though this event is being handled as part of gestures such as drag and band,
151        // continue forwarding to the GestureDetector. The detector needs to see the entire cluster
152        // of events in order to properly interpret other gestures, such as long press.
153        onTouchEvent(e);
154    }
155
156    private class MouseDelegate {
157        boolean onInterceptTouchEvent(InputEvent e) {
158            if (Events.isMouseDragEvent(e)) {
159                return mMouseDragListener.accept(e);
160            } else if (mBandController != null &&
161                    (mBandController.shouldStart(e) || mBandController.shouldStop(e))) {
162                return mBandController.onInterceptTouchEvent(e);
163            }
164            return false;
165        }
166
167        void onTouchEvent(InputEvent e) {
168            if (mBandController != null) {
169                mBandController.onTouchEvent(e);
170            }
171        }
172    }
173
174    private class TouchDelegate {
175        boolean onInterceptTouchEvent(InputEvent e) {
176            // Gesture Selector needs to be constantly fed events, so that when a long press does
177            // happen, we would have the last DOWN event that occurred to keep track of our anchor
178            // point
179            return mGestureSelector.onInterceptTouchEvent(e);
180        }
181
182        // TODO: Make this take just an InputEvent, no RecyclerView
183        void onTouchEvent(RecyclerView rv, InputEvent e) {
184            mGestureSelector.onTouchEvent(rv, e);
185        }
186    }
187
188    @Override
189    public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {}
190}
191