Android自定义FloatingActionButton滑动行为只隐藏不出现的问题小结

public class FabBehavior extends FloatingActionButton.Behavior{  private static final Interpolator INTERPOLATOR = new FastOutSlowInInterpolator();  private boolean mIsAnimatingOut = false;  public FabBehavior(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) {    if (Build.VERSION.SDK_INT >= 14) {      ViewCompat.animate(button).translationY(button.getHeight() + getMarginBottom(button)).setInterpolator(INTERPOLATOR).withLayer()          .setListener(new ViewPropertyAnimatorListener() {            public void onAnimationStart(View view) {              FabBehavior.this.mIsAnimatingOut = true;            }            public void onAnimationCancel(View view) {              FabBehavior.this.mIsAnimatingOut = false;            }            public void onAnimationEnd(View view) {              FabBehavior.this.mIsAnimatingOut = false;              view.setVisibility(View.GONE);            }          }).start();    } else {    }  }  // Same animation that FloatingActionButton.Behavior uses to show the FAB when the AppBarLayout enters  private void animateIn(FloatingActionButton button) {    button.setVisibility(View.VISIBLE);    if (Build.VERSION.SDK_INT >= 14) {      ViewCompat.animate(button).translationY(0)          .setInterpolator(INTERPOLATOR).withLayer().setListener(null)          .start();    } else {    }  }  private int getMarginBottom(View v) {    int marginBottom = 0;    final ViewGroup.LayoutParams layoutParams = v.getLayoutParams();    if (layoutParams instanceof ViewGroup.MarginLayoutParams) {      marginBottom = ((ViewGroup.MarginLayoutParams) layoutParams).bottomMargin;    }    return marginBottom;  }}

app:layout_behavior="com.normalframe.widgets.view.FabBehavior"