rewrote ScrollAwareFABBehavior.java to Kotlin. Can now implement FABAnimationBase to create different FAB animations

app/src/main/java/eu/kanade/tachiyomi/ui/base/fab/FABAnimationBase.kt

@@ -0,0 +1,31 @@
+package eu.kanade.tachiyomi.ui.base.fab
+
+import android.support.design.widget.CoordinatorLayout
+import android.support.design.widget.FloatingActionButton
+import android.support.v4.view.ViewCompat
+import android.view.View
+
+open class FABAnimationBase() : FloatingActionButton.Behavior()
+{
+    open val mIsAnimatingOut = false;
+
+    override fun onStartNestedScroll(coordinatorLayout: CoordinatorLayout?, child: FloatingActionButton?, directTargetChild: View?, target: View?, nestedScrollAxes: Int): Boolean {
+        // Ensure we react to vertical scrolling
+        return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL ||
+                super.onStartNestedScroll(coordinatorLayout, child, directTargetChild, target, nestedScrollAxes)
+    }
+
+    override fun onNestedScroll(coordinatorLayout: CoordinatorLayout?, child: FloatingActionButton?, target: View?, dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int) {
+        super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed)
+        if (dyConsumed > 0 && !this.mIsAnimatingOut && child!!.visibility == View.VISIBLE) {
+            // User scrolled down and the FAB is currently visible -> hide the FAB
+            animateOut(child)
+        } else if (dyConsumed < 0 && child!!.visibility != View.VISIBLE) {
+            // User scrolled up and the FAB is currently not visible -> show the FAB
+            animateIn(child)
+        }
+    }
+
+    open fun animateOut(button : FloatingActionButton) {}
+    open fun animateIn(button : FloatingActionButton) {}
+}

app/src/main/java/eu/kanade/tachiyomi/ui/base/fab/FABAnimationUpDown.kt

@@ -0,0 +1,54 @@
+package eu.kanade.tachiyomi.ui.base.fab
+
+import android.content.Context
+import android.support.design.widget.FloatingActionButton
+import android.support.v4.view.animation.FastOutSlowInInterpolator
+import android.util.AttributeSet
+import android.view.View
+import android.view.animation.Animation
+import android.view.animation.AnimationUtils
+import eu.kanade.tachiyomi.R
+
+class FABAnimationUpDown() : FABAnimationBase()
+{
+    override var mIsAnimatingOut: Boolean = false
+        get() = super.mIsAnimatingOut
+
+    private val INTERPOLATOR = FastOutSlowInInterpolator()
+
+    /**
+     * Needed to prevent NoSuchMethodException
+     */
+    constructor(ctx: Context, attrs: AttributeSet) : this() { }
+
+    override fun animateOut(button: FloatingActionButton) {
+        super.animateIn(button)
+        val anim = AnimationUtils.loadAnimation(button.context, R.anim.fab_hide_to_bottom)
+        anim.interpolator = INTERPOLATOR
+        anim.duration = 200L
+        anim.setAnimationListener(object : Animation.AnimationListener {
+            override fun onAnimationStart(animation: Animation) {
+                mIsAnimatingOut = true
+            }
+
+            override fun onAnimationEnd(animation: Animation) {
+                mIsAnimatingOut = false
+                button.visibility = View.GONE
+            }
+
+            override fun onAnimationRepeat(animation: Animation) {
+            }
+        })
+        button.startAnimation(anim)
+
+    }
+
+    override fun animateIn(button: FloatingActionButton) {
+        super.animateOut(button)
+        button.visibility = View.VISIBLE
+        val anim = AnimationUtils.loadAnimation(button.context, R.anim.fab_show_from_bottom)
+        anim.duration = 200L
+        anim.interpolator = INTERPOLATOR
+        button.startAnimation(anim)
+    }
+}

app/src/main/java/eu/kanade/tachiyomi/ui/base/fab/ScrollAwareFABBehavior.java

@@ -1,91 +0,0 @@
-/*
- * Copyright 2015 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package eu.kanade.tachiyomi.ui.base.fab;
-
-import android.content.Context;
-import android.support.design.widget.CoordinatorLayout;
-import android.support.design.widget.FloatingActionButton;
-import android.support.v4.view.ViewCompat;
-import android.support.v4.view.animation.FastOutSlowInInterpolator;
-import android.util.AttributeSet;
-import android.view.View;
-import android.view.animation.Animation;
-import android.view.animation.AnimationUtils;
-import android.view.animation.Interpolator;
-
-import eu.kanade.tachiyomi.R;
-
-public class ScrollAwareFABBehavior extends FloatingActionButton.Behavior {
-    private static final Interpolator INTERPOLATOR = new FastOutSlowInInterpolator();
-    private boolean mIsAnimatingOut = false;
-
-    public ScrollAwareFABBehavior(Context context, AttributeSet attrs) {
-        super();
-    }
-
-    @Override
-    public boolean onStartNestedScroll(final CoordinatorLayout coordinatorLayout, final FloatingActionButton child,
-                                       final View directTargetChild, final View target, final int nestedScrollAxes) {
-        // Ensure we react to vertical scrolling
-        return nestedScrollAxes == ViewCompat.SCROLL_AXIS_VERTICAL
-                || super.onStartNestedScroll(coordinatorLayout, child, directTargetChild, target, nestedScrollAxes);
-    }
-
-    @Override
-    public void onNestedScroll(final CoordinatorLayout coordinatorLayout, final FloatingActionButton child,
-                               final View target, final int dxConsumed, final int dyConsumed,
-                               final int dxUnconsumed, final int dyUnconsumed) {
-        super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed);
-        if (dyConsumed > 0 && !this.mIsAnimatingOut && child.getVisibility() == View.VISIBLE) {
-            // User scrolled down and the FAB is currently visible -> hide the FAB
-            animateOut(child);
-        } else if (dyConsumed < 0 && child.getVisibility() != View.VISIBLE) {
-            // User scrolled up and the FAB is currently not visible -> show the FAB
-            animateIn(child);
-        }
-    }
-
-    // Same animation that FloatingActionButton.Behavior uses to hide the FAB when the AppBarLayout exits
-    private void animateOut(final FloatingActionButton button) {
-            Animation anim = AnimationUtils.loadAnimation(button.getContext(), R.anim.fab_hide_to_bottom);
-            anim.setInterpolator(INTERPOLATOR);
-            anim.setDuration(200L);
-            anim.setAnimationListener(new Animation.AnimationListener() {
-                public void onAnimationStart(Animation animation) {
-                    ScrollAwareFABBehavior.this.mIsAnimatingOut = true;
-                }
-
-                public void onAnimationEnd(Animation animation) {
-                    ScrollAwareFABBehavior.this.mIsAnimatingOut = false;
-                    button.setVisibility(View.GONE);
-                }
-
-                @Override
-                public void onAnimationRepeat(final Animation animation) {
-                }
-            });
-            button.startAnimation(anim);
-    }
-
-    // Same animation that FloatingActionButton.Behavior uses to show the FAB when the AppBarLayout enters
-    private void animateIn(FloatingActionButton button) {
-        button.setVisibility(View.VISIBLE);
-            Animation anim = AnimationUtils.loadAnimation(button.getContext(), R.anim.fab_show_from_bottom);
-            anim.setDuration(200L);
-            anim.setInterpolator(INTERPOLATOR);
-            button.startAnimation(anim);
-    }
-}

app/src/main/res/layout/activity_edit_categories.xml

@@ -27,6 +27,6 @@
         app:backgroundTint="@color/colorPrimary"
         app:layout_anchor="@id/categories_list"
         app:layout_anchorGravity="bottom|right|end"
-        app:layout_behavior="eu.kanade.tachiyomi.ui.base.fab.ScrollAwareFABBehavior"/>
+        app:layout_behavior="eu.kanade.tachiyomi.ui.base.fab.FABAnimationUpDown"/>
 
 </android.support.design.widget.CoordinatorLayout>