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.os.Handler;
  26 import android.view.MotionEvent;
  27 import android.view.ViewGroup;
  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 static final int AUTO_SHOW_DELAY_MILLS = 4000;
  42     private final FloatingActionButton fab;
  43     private boolean wantedFabState = FAB_SHOWN;
  44     private ViewPropertyAnimator fabSlideAnimator;
  45     private int fabVerticalOffset;
  46     public FabManager(FloatingActionButton fab) {
  47         this.fab = fab;
  48     }
  49     public static void handle(FabHandler fabHandler, RecyclerView recyclerView) {
  50         new ScrollFabHandler(fabHandler, recyclerView);
  51     }
  52     private void slideFabTo(int target, long duration, TimeInterpolator interpolator) {
  53         fabSlideAnimator = fab.animate()
  54                               .translationY((float) target)
  55                               .setInterpolator(interpolator)
  56                               .setDuration(duration)
  57                               .setListener(new AnimatorListenerAdapter() {
  58                                   public void onAnimationEnd(Animator animation) {
  59                                       fabSlideAnimator = null;
  60                                   }
  61                               });
  62     }
  63     public void showFab() {
  64         if (wantedFabState == FAB_SHOWN)
  65             return;
  66
  67 //        b.btnAddTransaction.show();
  68         if (this.fabSlideAnimator != null) {
  69             this.fabSlideAnimator.cancel();
  70             fab.clearAnimation();
  71         }
  72
  73         wantedFabState = FAB_SHOWN;
  74         slideFabTo(0, 200L,
  75                 com.google.android.material.animation.AnimationUtils.LINEAR_OUT_SLOW_IN_INTERPOLATOR);
  76     }
  77     public void hideFab() {
  78         if (wantedFabState == FAB_HIDDEN)
  79             return;
  80
  81         calcVerticalFabOffset();
  82
  83 //        b.btnAddTransaction.hide();
  84         if (this.fabSlideAnimator != null) {
  85             this.fabSlideAnimator.cancel();
  86             fab.clearAnimation();
  87         }
  88
  89         wantedFabState = FAB_HIDDEN;
  90         slideFabTo(fabVerticalOffset, 150L,
  91                 com.google.android.material.animation.AnimationUtils.FAST_OUT_LINEAR_IN_INTERPOLATOR);
  92     }
  93     private void calcVerticalFabOffset() {
  94         if (fabVerticalOffset > 0)
  95             return;// already calculated
  96         fab.measure(0, 0);
  97
  98         int height = fab.getMeasuredHeight();
  99
 100         int bottomMargin;
 101
 102         ViewGroup.LayoutParams layoutParams = fab.getLayoutParams();
 103         if (layoutParams instanceof ViewGroup.MarginLayoutParams)
 104             bottomMargin = ((ViewGroup.MarginLayoutParams) layoutParams).bottomMargin;
 105         else
 106             throw new RuntimeException("Unsupported layout params " + layoutParams.getClass()
 107                                                                                   .getCanonicalName());
 108
 109         fabVerticalOffset = height + bottomMargin;
 110     }
 111     public interface FabHandler {
 112         Context getContext();
 113
 114         void showManagedFab();
 115
 116         void hideManagedFab();
 117     }
 118
 119     public static class ScrollFabHandler {
 120         final private FabHandler fabHandler;
 121         private int generation = 0;
 122         @SuppressLint("ClickableViewAccessibility")
 123         ScrollFabHandler(FabHandler fabHandler, RecyclerView recyclerView) {
 124             this.fabHandler = fabHandler;
 125             final float triggerAbsolutePixels = DimensionUtils.dp2px(fabHandler.getContext(), 20f);
 126             final float triggerRelativePixels = triggerAbsolutePixels / 4f;
 127             recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
 128                 @Override
 129                 public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
 130                     Logger.debug("touch", "Scrolled " + dy);
 131                     if (dy <= 0) {
 132                         showFab();
 133                     }
 134                     else
 135                         hideFab();
 136
 137                     super.onScrolled(recyclerView, dx, dy);
 138                 }
 139             });
 140             recyclerView.addOnItemTouchListener(new RecyclerView.SimpleOnItemTouchListener() {
 141                 private float absoluteAnchor = -1;
 142                 @Override
 143                 public boolean onInterceptTouchEvent(@NonNull RecyclerView rv,
 144                                                      @NonNull MotionEvent e) {
 145                     switch (e.getActionMasked()) {
 146                         case MotionEvent.ACTION_DOWN:
 147                             absoluteAnchor = e.getRawY();
 148 //                        Logger.debug("touch",
 149 //                                String.format(Locale.US, "Touch down at %4.2f", absoluteAnchor));
 150                             break;
 151                         case MotionEvent.ACTION_MOVE:
 152                             if (absoluteAnchor < 0)
 153                                 break;
 154
 155                             final float absoluteY = e.getRawY();
 156 //                        Logger.debug("touch", String.format(Locale.US, "Move to %4.2f",
 157 //                        absoluteY));
 158
 159                             if (absoluteY > absoluteAnchor + triggerAbsolutePixels) {
 160                                 // swipe down
 161 //                            Logger.debug("touch", "SHOW");
 162                                 showFab();
 163                                 absoluteAnchor = absoluteY;
 164                             }
 165                             else if (absoluteY < absoluteAnchor - triggerAbsolutePixels) {
 166                                 // swipe up
 167 //                            Logger.debug("touch", "HIDE");
 168                                 hideFab();
 169                                 absoluteAnchor = absoluteY;
 170                             }
 171
 172                             break;
 173                     }
 174                     return false;
 175                 }
 176             });
 177         }
 178         private void hideFab() {
 179             generation++;
 180             int thisGeneration = generation;
 181             fabHandler.hideManagedFab();
 182             new Handler().postDelayed(() -> {
 183                 if (generation != thisGeneration)
 184                     return;
 185
 186                 showFab();
 187             }, AUTO_SHOW_DELAY_MILLS);
 188         }
 189         private void showFab() {
 190             generation++;
 191             fabHandler.showManagedFab();
 192         }
 193     }
 194 }