improved fling behavior, added tab indicator dots, added next video in related videos

app/src/main/java/android/support/design/widget/FlingBehavior.java

@@ -0,0 +1,143 @@
+package android.support.design.widget;
+
+import android.animation.ValueAnimator;
+import android.content.Context;
+import android.os.Parcelable;
+import android.support.annotation.NonNull;
+import android.util.AttributeSet;
+import android.view.View;
+
+// check this https://github.com/ToDou/appbarlayout-spring-behavior/blob/master/appbarspring/src/main/java/android/support/design/widget/AppBarFlingFixBehavior.java
+public final class FlingBehavior extends AppBarLayout.Behavior {
+
+    private ValueAnimator mOffsetAnimator;
+    private static final int MAX_OFFSET_ANIMATION_DURATION = 600; // ms
+
+    public FlingBehavior() {
+    }
+
+    public FlingBehavior(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    @Override
+    public boolean onStartNestedScroll(CoordinatorLayout parent, AppBarLayout child, View directTargetChild, View target, int nestedScrollAxes, int type) {
+        return super.onStartNestedScroll(parent, child, directTargetChild, target, nestedScrollAxes, type);
+    }
+
+    @Override
+    public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, int dx, int dy, int[] consumed, int type) {
+        if (dy != 0) {
+            int val = child.getBottom();
+            if (val != 0) {
+                int min, max;
+                if (dy < 0) {
+                    // We're scrolling down
+                } else {
+                    // We're scrolling up
+                    min = -child.getUpNestedPreScrollRange();
+                    max = 0;
+                    consumed[1] = scroll(coordinatorLayout, child, dy, min, max);
+                }
+            }
+        }
+    }
+
+    @Override
+    public void onNestedScroll(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed, int type) {
+        super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed, type);
+    }
+
+    @Override
+    public void onStopNestedScroll(CoordinatorLayout coordinatorLayout, AppBarLayout abl, View target, int type) {
+        super.onStopNestedScroll(coordinatorLayout, abl, target, type);
+    }
+
+    @Override
+    public boolean onMeasureChild(CoordinatorLayout parent, AppBarLayout child, int parentWidthMeasureSpec, int widthUsed, int parentHeightMeasureSpec, int heightUsed) {
+        return super.onMeasureChild(parent, child, parentWidthMeasureSpec, widthUsed, parentHeightMeasureSpec, heightUsed);
+    }
+
+    @Override
+    public Parcelable onSaveInstanceState(CoordinatorLayout parent, AppBarLayout abl) {
+        return super.onSaveInstanceState(parent, abl);
+    }
+
+    @Override
+    public void onRestoreInstanceState(CoordinatorLayout parent, AppBarLayout appBarLayout, Parcelable state) {
+        super.onRestoreInstanceState(parent, appBarLayout, state);
+    }
+
+    @Override
+    public boolean onNestedPreFling(@NonNull CoordinatorLayout coordinatorLayout, @NonNull AppBarLayout child, @NonNull View target, float velocityX, float velocityY) {
+
+        if (velocityY != 0) {
+            if (velocityY < 0) {
+                // We're flinging down
+                int val = child.getBottom();
+                if (val != 0) {
+                    final int targetScroll =
+                            +child.getDownNestedPreScrollRange();
+                    animateOffsetTo(coordinatorLayout, child, targetScroll, velocityY);
+                }
+
+            } else {
+                // We're flinging up
+                int val = child.getBottom();
+                if (val != 0) {
+                    final int targetScroll = -child.getUpNestedPreScrollRange();
+                    if (getTopBottomOffsetForScrollingSibling() > targetScroll) {
+                        animateOffsetTo(coordinatorLayout, child, targetScroll, velocityY);
+                    }
+                }
+            }
+        }
+
+        return super.onNestedPreFling(coordinatorLayout, child, target, velocityX, velocityY);
+    }
+
+    private void animateOffsetTo(final CoordinatorLayout coordinatorLayout,
+                                 final AppBarLayout child, final int offset, float velocity) {
+        final int distance = Math.abs(getTopBottomOffsetForScrollingSibling() - offset);
+
+        final int duration;
+        velocity = Math.abs(velocity);
+        if (velocity > 0) {
+            duration = 3 * Math.round(1000 * (distance / velocity));
+        } else {
+            final float distanceRatio = (float) distance / child.getHeight();
+            duration = (int) ((distanceRatio + 1) * 150);
+        }
+
+        animateOffsetWithDuration(coordinatorLayout, child, offset, duration);
+    }
+
+    private void animateOffsetWithDuration(final CoordinatorLayout coordinatorLayout,
+                                           final AppBarLayout child, final int offset, final int duration) {
+        final int currentOffset = getTopBottomOffsetForScrollingSibling();
+        if (currentOffset == offset) {
+            if (mOffsetAnimator != null && mOffsetAnimator.isRunning()) {
+                mOffsetAnimator.cancel();
+            }
+            return;
+        }
+
+        if (mOffsetAnimator == null) {
+            mOffsetAnimator = new ValueAnimator();
+            mOffsetAnimator.setInterpolator(AnimationUtils.DECELERATE_INTERPOLATOR);
+            mOffsetAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
+                @Override
+                public void onAnimationUpdate(ValueAnimator animator) {
+                    setHeaderTopBottomOffset(coordinatorLayout, child,
+                            (Integer) animator.getAnimatedValue());
+                }
+            });
+        } else {
+            mOffsetAnimator.cancel();
+        }
+
+        mOffsetAnimator.setDuration(Math.min(duration, MAX_OFFSET_ANIMATION_DURATION));
+        mOffsetAnimator.setIntValues(currentOffset, offset);
+        mOffsetAnimator.start();
+    }
+}