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 }