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.os.Looper;
  27 import android.view.MotionEvent;
  28 import android.view.ViewGroup;
  29 import android.view.ViewPropertyAnimator;
  30
  31 import androidx.annotation.NonNull;
  32 import androidx.recyclerview.widget.RecyclerView;
  33
  34 import com.google.android.material.floatingactionbutton.FloatingActionButton;
  35
  36 import net.ktnx.mobileledger.utils.DimensionUtils;
  37 import net.ktnx.mobileledger.utils.Logger;
  38
  39 public class FabManager {
  40     private static final boolean FAB_SHOWN = true;
  41     private static final boolean FAB_HIDDEN = false;
  42     private static final int AUTO_SHOW_DELAY_MILLS = 4000;
  43     private final FloatingActionButton fab;
  44     private boolean wantedFabState = FAB_SHOWN;
  45     private ViewPropertyAnimator fabSlideAnimator;
  46     private int fabVerticalOffset;
  47     public FabManager(FloatingActionButton fab) {
  48         this.fab = fab;
  49     }
  50     public static void handle(FabHandler fabHandler, RecyclerView recyclerView) {
  51         new ScrollFabHandler(fabHandler, recyclerView);
  52     }
  53     private void slideFabTo(int target, long duration, TimeInterpolator interpolator) {
  54         fabSlideAnimator = fab.animate()
  55                               .translationY((float) target)
  56                               .setInterpolator(interpolator)
  57                               .setDuration(duration)
  58                               .setListener(new AnimatorListenerAdapter() {
  59                                   public void onAnimationEnd(Animator animation) {
  60                                       fabSlideAnimator = null;
  61                                   }
  62                               });
  63     }
  64     public void showFab() {
  65         if (wantedFabState == FAB_SHOWN) {
  66 //            Logger.debug("fab", "Ignoring request to show already visible FAB");
  67             return;
  68         }
  69
  70 //        b.btnAddTransaction.show();
  71         if (this.fabSlideAnimator != null) {
  72             this.fabSlideAnimator.cancel();
  73             fab.clearAnimation();
  74         }
  75
  76         Logger.debug("fab", "Showing FAB");
  77         wantedFabState = FAB_SHOWN;
  78         slideFabTo(0, 200L,
  79                 com.google.android.material.animation.AnimationUtils.LINEAR_OUT_SLOW_IN_INTERPOLATOR);
  80     }
  81     public void hideFab() {
  82         if (wantedFabState == FAB_HIDDEN) {
  83 //            Logger.debug("fab", "Ignoring request to hide FAB -- already hidden");
  84             return;
  85         }
  86
  87         calcVerticalFabOffset();
  88
  89 //        b.btnAddTransaction.hide();
  90         if (this.fabSlideAnimator != null) {
  91             this.fabSlideAnimator.cancel();
  92             fab.clearAnimation();
  93         }
  94
  95         Logger.debug("fab", "Hiding FAB");
  96         wantedFabState = FAB_HIDDEN;
  97         slideFabTo(fabVerticalOffset, 150L,
  98                 com.google.android.material.animation.AnimationUtils.FAST_OUT_LINEAR_IN_INTERPOLATOR);
  99     }
 100     private void calcVerticalFabOffset() {
 101         if (fabVerticalOffset > 0)
 102             return;// already calculated
 103         fab.measure(0, 0);
 104
 105         int height = fab.getMeasuredHeight();
 106
 107         int bottomMargin;
 108
 109         ViewGroup.LayoutParams layoutParams = fab.getLayoutParams();
 110         if (layoutParams instanceof ViewGroup.MarginLayoutParams)
 111             bottomMargin = ((ViewGroup.MarginLayoutParams) layoutParams).bottomMargin;
 112         else
 113             throw new RuntimeException("Unsupported layout params " + layoutParams.getClass()
 114                                                                                   .getCanonicalName());
 115
 116         fabVerticalOffset = height + bottomMargin;
 117     }
 118     public interface FabHandler {
 119         Context getContext();
 120
 121         void showManagedFab();
 122
 123         void hideManagedFab();
 124     }
 125
 126     public static class ScrollFabHandler {
 127         final private FabHandler fabHandler;
 128         private int generation = 0;
 129         @SuppressLint("ClickableViewAccessibility")
 130         ScrollFabHandler(FabHandler fabHandler, RecyclerView recyclerView) {
 131             this.fabHandler = fabHandler;
 132             final float triggerAbsolutePixels = DimensionUtils.dp2px(fabHandler.getContext(), 20f);
 133             final float triggerRelativePixels = triggerAbsolutePixels / 4f;
 134             recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
 135                 @Override
 136                 public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
 137 //                    Logger.debug("touch", "Scrolled " + dy);
 138                     if (dy <= 0) {
 139                         showFab();
 140                     }
 141                     else
 142                         hideFab();
 143
 144                     super.onScrolled(recyclerView, dx, dy);
 145                 }
 146             });
 147             recyclerView.addOnItemTouchListener(new RecyclerView.SimpleOnItemTouchListener() {
 148                 private float absoluteAnchor = -1;
 149                 @Override
 150                 public boolean onInterceptTouchEvent(@NonNull RecyclerView rv,
 151                                                      @NonNull MotionEvent e) {
 152                     switch (e.getActionMasked()) {
 153                         case MotionEvent.ACTION_DOWN:
 154                             absoluteAnchor = e.getRawY();
 155 //                        Logger.debug("touch",
 156 //                                String.format(Locale.US, "Touch down at %4.2f", absoluteAnchor));
 157                             break;
 158                         case MotionEvent.ACTION_MOVE:
 159                             if (absoluteAnchor < 0)
 160                                 break;
 161
 162                             final float absoluteY = e.getRawY();
 163 //                        Logger.debug("touch", String.format(Locale.US, "Move to %4.2f",
 164 //                        absoluteY));
 165
 166                             if (absoluteY > absoluteAnchor + triggerAbsolutePixels) {
 167                                 // swipe down
 168 //                            Logger.debug("touch", "SHOW");
 169                                 showFab();
 170                                 absoluteAnchor = absoluteY;
 171                             }
 172                             else if (absoluteY < absoluteAnchor - triggerAbsolutePixels) {
 173                                 // swipe up
 174 //                            Logger.debug("touch", "HIDE");
 175                                 hideFab();
 176                                 absoluteAnchor = absoluteY;
 177                             }
 178
 179                             break;
 180                     }
 181                     return false;
 182                 }
 183             });
 184         }
 185         private void hideFab() {
 186             generation++;
 187             int thisGeneration = generation;
 188             fabHandler.hideManagedFab();
 189             new Handler(Looper.getMainLooper()).postDelayed(() -> {
 190                 if (generation != thisGeneration)
 191                     return;
 192
 193                 showFab();
 194             }, AUTO_SHOW_DELAY_MILLS);
 195         }
 196         private void showFab() {
 197             generation++;
 198             fabHandler.showManagedFab();
 199         }
 200     }
 201 }