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