Add automatically hide scroller when not scrolling. (default: automat…

…ically hide)

Introduced these public methods:

- AbsRecyclerViewFastScroller.isFastScrollAlwaysVisible()
- AbsRecyclerViewFastScroller.setFastScrollAlwaysVisible(boolean alwaysVisible)

Application/src/main/java/com/example/recyclerviewfastscroller/ui/scroller/AbsRecyclerViewFastScroller.java

@@ -8,12 +8,14 @@
 import android.os.Build.VERSION_CODES;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
+import android.support.v4.view.ViewCompat;
 import android.support.v7.widget.RecyclerView;
 import android.support.v7.widget.RecyclerView.OnScrollListener;
 import android.util.AttributeSet;
 import android.view.LayoutInflater;
 import android.view.MotionEvent;
 import android.view.View;
+import android.view.animation.Animation;
 import android.widget.FrameLayout;
 import android.widget.SectionIndexer;
 
@@ -31,6 +33,14 @@
 public abstract class AbsRecyclerViewFastScroller extends FrameLayout implements RecyclerViewScroller {
 
     private static final int[] STYLEABLE = R.styleable.AbsRecyclerViewFastScroller;
+
+    private static final int AUTO_HIDE_SCROLLER_TIMEOUT_MILLS = 1000;
+
+    private static final int CURRENT_ANIMATION_NONE = 0;
+    private static final int CURRENT_ANIMATION_SHOW = 1;
+    private static final int CURRENT_ANIMATION_HIDE = 2;
+
+
     /** The long bar along which a handle travels */
     protected final View mBar;
     /** The handle that signifies the user's progress in the list */
@@ -47,6 +57,12 @@ public abstract class AbsRecyclerViewFastScroller extends FrameLayout implements
      * {@link OnScrollListener} an abstract class instead of an interface. Hmmm */
     protected OnScrollListener mOnScrollListener;
 
+    /** true: always show the scroller, false: hide the scroller automatically */
+    private boolean mFastScrollAlwaysVisible = false;
+    /** Type of the view animation (CURRENT_ANIMATION_xxx) */
+    private int mCurrentAnimationType = CURRENT_ANIMATION_NONE;
+    private Runnable mAutoHideProcessRunnable;
+
     public AbsRecyclerViewFastScroller(Context context) {
         this(context, null, 0);
     }
@@ -83,6 +99,29 @@ public AbsRecyclerViewFastScroller(Context context, AttributeSet attrs, int defS
         setOnTouchListener(new FastScrollerTouchListener(this));
     }
 
+    @Override
+    protected void onAttachedToWindow() {
+        super.onAttachedToWindow();
+
+        mAutoHideProcessRunnable = new Runnable() {
+            @Override
+            public void run() {
+                hideWithAnimation();
+            }
+        };
+        if (!mFastScrollAlwaysVisible) {
+            hide();
+        }
+    }
+
+    @Override
+    protected void onDetachedFromWindow() {
+        super.onDetachedFromWindow();
+
+        cancelAutoHideScrollerProcess();
+        mAutoHideProcessRunnable = null;
+    }
+
     private void applyCustomAttributesToView(View view, Drawable drawable, int color) {
         if (drawable != null) {
             setViewBackground(view, drawable);
@@ -183,12 +222,145 @@ public OnScrollListener getOnScrollListener() {
                 public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                     float scrollProgress = getScrollProgressCalculator().calculateScrollProgress(recyclerView);
                     moveHandleToPosition(scrollProgress);
+
+                    if (!mFastScrollAlwaysVisible) {
+                        showWithAnimation();
+                        scheduleAutoHideScrollerProcess();
+                    }
                 }
             };
         }
         return mOnScrollListener;
     }
 
+    /**
+     * Returns true if the fast scroller is set to always show on this view.
+     *
+     * @return true if the fast scroller will always show
+     */
+    public boolean isFastScrollAlwaysVisible() {
+        return mFastScrollAlwaysVisible;
+    }
+
+    /**
+     * Set whether or not the fast scroller should always be shown.
+     *
+     * @param alwaysVisible true if the fast scroller should always be displayed, false otherwise
+     */
+    public void setFastScrollAlwaysVisible(boolean alwaysVisible) {
+        if (mFastScrollAlwaysVisible == alwaysVisible) {
+            return;
+        }
+        mFastScrollAlwaysVisible = alwaysVisible;
+        if (mFastScrollAlwaysVisible) {
+            show();
+        } else {
+            cancelAutoHideScrollerProcess();
+        }
+    }
+
+    private void scheduleAutoHideScrollerProcess() {
+        cancelAutoHideScrollerProcess();
+
+        if (!mFastScrollAlwaysVisible) {
+            postDelayed(mAutoHideProcessRunnable, AUTO_HIDE_SCROLLER_TIMEOUT_MILLS);
+        }
+    }
+
+    private void cancelAutoHideScrollerProcess() {
+        removeCallbacks(mAutoHideProcessRunnable);
+    }
+
+    private void show() {
+        if (getAnimation() != null) {
+            getAnimation().cancel();
+        }
+
+        ViewCompat.setTranslationX(this, 0);
+        ViewCompat.setTranslationY(this, 0);
+
+        setVisibility(View.VISIBLE);
+    }
+
+    private void hide() {
+        if (getAnimation() != null) {
+            getAnimation().cancel();
+        }
+        setVisibility(View.INVISIBLE);
+    }
+
+    private void showWithAnimation() {
+        if ((mCurrentAnimationType == CURRENT_ANIMATION_SHOW) || (getVisibility() == View.VISIBLE)) {
+            return;
+        }
+
+        if (getAnimation() != null) {
+            getAnimation().cancel();
+        }
+
+        final Animation anim = loadShowAnimation();
+
+        if (anim != null) {
+            anim.setAnimationListener(new Animation.AnimationListener() {
+                @Override
+                public void onAnimationStart(Animation animation) {
+                    setVisibility(View.VISIBLE);
+                }
+
+                @Override
+                public void onAnimationEnd(Animation animation) {
+                    mCurrentAnimationType = CURRENT_ANIMATION_NONE;
+                }
+
+                @Override
+                public void onAnimationRepeat(Animation animation) {
+                }
+            });
+
+            mCurrentAnimationType = CURRENT_ANIMATION_SHOW;
+
+            startAnimation(anim);
+        } else {
+            show();
+        }
+    }
+
+    private void hideWithAnimation() {
+        if ((mCurrentAnimationType == CURRENT_ANIMATION_HIDE) || (getVisibility() != View.VISIBLE)) {
+            return;
+        }
+
+        if (getAnimation() != null) {
+            getAnimation().cancel();
+        }
+
+        final Animation anim = loadHideAnimation();
+
+        if (anim != null) {
+            anim.setAnimationListener(new Animation.AnimationListener() {
+                @Override
+                public void onAnimationStart(Animation animation) {
+                }
+
+                @Override
+                public void onAnimationEnd(Animation animation) {
+                    mCurrentAnimationType = CURRENT_ANIMATION_NONE;
+                    setVisibility(View.INVISIBLE);
+                }
+
+                @Override
+                public void onAnimationRepeat(Animation animation) {
+                }
+            });
+
+            mCurrentAnimationType = CURRENT_ANIMATION_HIDE;
+
+            startAnimation(anim);
+        } else {
+            hide();
+        }
+    }
+
     /**
      * Takes a touch event and determines how much scroll progress this translates into
      * @param event touch event received by the layout
@@ -217,4 +389,15 @@ public float getScrollProgress(MotionEvent event) {
      */
     public abstract void moveHandleToPosition(float scrollProgress);
 
+    /**
+     * Loads scroller show animation
+     * @return animation which is used for the showWithAnimation() method
+     */
+    protected abstract Animation loadShowAnimation();
+
+    /**
+     * Loads scroller hide animation
+     * @return animation which is used for the hideWithAnimation() method
+     */
+    protected abstract Animation loadHideAnimation();
 }

Application/src/main/java/com/example/recyclerviewfastscroller/ui/scroller/vertical/VerticalRecyclerViewFastScroller.java

@@ -4,6 +4,8 @@
 import android.support.v7.widget.LinearLayoutManager;
 import android.support.v7.widget.RecyclerView;
 import android.util.AttributeSet;
+import android.view.animation.Animation;
+import android.view.animation.AnimationUtils;
 
 import com.example.android.recyclerview.R;
 import com.example.recyclerviewfastscroller.ui.scroller.AbsRecyclerViewFastScroller;
@@ -50,6 +52,16 @@ public void moveHandleToPosition(float scrollProgress) {
         mHandle.setY(mScreenPositionCalculator.getYPositionFromScrollProgress(scrollProgress));
     }
 
+    @Override
+    protected Animation loadShowAnimation() {
+        return AnimationUtils.loadAnimation(getContext(), R.anim.fast_scroller_slide_in_right);
+    }
+
+    @Override
+    protected Animation loadHideAnimation() {
+        return AnimationUtils.loadAnimation(getContext(), R.anim.fast_scroller_slide_out_right);
+    }
+
     @Override
     public void onLayout(boolean changed, int left, int top, int right, int bottom) {
         super.onLayout(changed, left, top, right, bottom);

Application/src/main/res/anim/fast_scroller_slide_in_right.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<translate xmlns:android="http://schemas.android.com/apk/res/android"
+    android:interpolator="@android:anim/accelerate_interpolator"
+    android:fromXDelta="100%" android:toXDelta="0"
+    android:duration="@android:integer/config_shortAnimTime"/>

Application/src/main/res/anim/fast_scroller_slide_out_right.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<translate xmlns:android="http://schemas.android.com/apk/res/android"
+    android:interpolator="@android:anim/accelerate_interpolator"
+    android:fromXDelta="0" android:toXDelta="100%"
+    android:duration="@android:integer/config_shortAnimTime"/>