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parent is guaranteed to be a View here, or null
[mobile-ledger.git] / app / src / main / java / net / ktnx / mobileledger / ui / FabManager.java
1 /*
2  * Copyright © 2021 Damyan Ivanov.
3  * This file is part of MoLe.
4  * MoLe is free software: you can distribute it and/or modify it
5  * under the term of the GNU General Public License as published by
6  * the Free Software Foundation, either version 3 of the License, or
7  * (at your opinion), any later version.
8  *
9  * MoLe is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12  * GNU General Public License terms for details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with MoLe. If not, see <https://www.gnu.org/licenses/>.
16  */
17
18 package net.ktnx.mobileledger.ui;
19
20 import android.animation.Animator;
21 import android.animation.AnimatorListenerAdapter;
22 import android.animation.TimeInterpolator;
23 import android.annotation.SuppressLint;
24 import android.content.Context;
25 import android.view.MotionEvent;
26 import android.view.View;
27 import android.view.ViewParent;
28 import android.view.ViewPropertyAnimator;
29
30 import androidx.annotation.NonNull;
31 import androidx.recyclerview.widget.RecyclerView;
32
33 import com.google.android.material.floatingactionbutton.FloatingActionButton;
34
35 import net.ktnx.mobileledger.utils.DimensionUtils;
36 import net.ktnx.mobileledger.utils.Logger;
37
38 public class FabManager {
39     private static final boolean FAB_SHOWN = true;
40     private static final boolean FAB_HIDDEN = false;
41     private final FloatingActionButton fab;
42     private boolean wantedFabState = FAB_SHOWN;
43     private ViewPropertyAnimator fabSlideAnimator;
44     private int fabVerticalOffset;
45     public FabManager(FloatingActionButton fab) {
46         this.fab = fab;
47     }
48     @SuppressLint("ClickableViewAccessibility")
49     public static void handle(FabHandler activity, RecyclerView recyclerView) {
50         final float triggerAbsolutePixels = DimensionUtils.dp2px(activity.getContext(), 20f);
51         final float triggerRelativePixels = triggerAbsolutePixels / 4f;
52         recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
53             @Override
54             public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
55                 Logger.debug("touch", "Scrolled " + dy);
56                 if (dy <= 0)
57                     activity.showManagedFab();
58                 else
59                     activity.hideManagedFab();
60
61                 super.onScrolled(recyclerView, dx, dy);
62             }
63         });
64         recyclerView.addOnItemTouchListener(new RecyclerView.SimpleOnItemTouchListener() {
65             private float absoluteAnchor = -1;
66             @Override
67             public boolean onInterceptTouchEvent(@NonNull RecyclerView rv, @NonNull MotionEvent e) {
68                 switch (e.getActionMasked()) {
69                     case MotionEvent.ACTION_DOWN:
70                         absoluteAnchor = e.getRawY();
71 //                        Logger.debug("touch",
72 //                                String.format(Locale.US, "Touch down at %4.2f", absoluteAnchor));
73                         break;
74                     case MotionEvent.ACTION_MOVE:
75                         if (absoluteAnchor < 0)
76                             break;
77
78                         final float absoluteY = e.getRawY();
79 //                        Logger.debug("touch", String.format(Locale.US, "Move to %4.2f", absoluteY));
80
81                         if (absoluteY > absoluteAnchor + triggerAbsolutePixels) {
82                             // swipe down
83 //                            Logger.debug("touch", "SHOW");
84                             activity.showManagedFab();
85                             absoluteAnchor = absoluteY;
86                         }
87                         else if (absoluteY < absoluteAnchor - triggerAbsolutePixels) {
88                             // swipe up
89 //                            Logger.debug("touch", "HIDE");
90                             activity.hideManagedFab();
91                             absoluteAnchor = absoluteY;
92                         }
93
94                         break;
95                 }
96                 return false;
97             }
98         });
99     }
100     private void slideFabTo(int target, long duration, TimeInterpolator interpolator) {
101         fabSlideAnimator = fab.animate()
102                               .translationY((float) target)
103                               .setInterpolator(interpolator)
104                               .setDuration(duration)
105                               .setListener(new AnimatorListenerAdapter() {
106                                   public void onAnimationEnd(Animator animation) {
107                                       fabSlideAnimator = null;
108                                   }
109                               });
110     }
111     public void showFab() {
112         if (wantedFabState == FAB_SHOWN)
113             return;
114
115 //        b.btnAddTransaction.show();
116         if (this.fabSlideAnimator != null) {
117             this.fabSlideAnimator.cancel();
118             fab.clearAnimation();
119         }
120
121         wantedFabState = FAB_SHOWN;
122         slideFabTo(0, 200L,
123                 com.google.android.material.animation.AnimationUtils.LINEAR_OUT_SLOW_IN_INTERPOLATOR);
124     }
125     public void hideFab() {
126         if (wantedFabState == FAB_HIDDEN)
127             return;
128
129         calcVerticalFabOffset();
130
131 //        b.btnAddTransaction.hide();
132         if (this.fabSlideAnimator != null) {
133             this.fabSlideAnimator.cancel();
134             fab.clearAnimation();
135         }
136
137         wantedFabState = FAB_HIDDEN;
138         slideFabTo(fabVerticalOffset, 150L,
139                 com.google.android.material.animation.AnimationUtils.FAST_OUT_LINEAR_IN_INTERPOLATOR);
140     }
141     private void calcVerticalFabOffset() {
142         if (fabVerticalOffset > 0)
143             return;// already calculated
144         int top = fab.getTop();
145         ViewParent parent = fab.getParent();
146         while (parent != null && !(parent instanceof View))
147             parent = parent.getParent();
148
149         if (parent != null) {
150             View parentView = (View) parent;
151             int parentHeight = parentView.getHeight();
152             fabVerticalOffset = parentHeight - top;
153         }
154     }
155     public interface FabHandler {
156         Context getContext();
157
158         void showManagedFab();
159
160         void hideManagedFab();
161     }
162 }