滑动底部工具条显示与隐藏

public class ScrollerBottomLayoutDelegation { private NestedScrollViewmNestedScroller; private ViewGroup mBottomLayout; private ScrollerBottomLayoutDelegation(NestedScrollView scroller, ViewGroup view){ this.mNestedScroller = scroller; this.mBottomLayout = view; init(); } /** * 开始初始化代理 */ private void init() { mNestedScroller.setOnScrollChangeListener(new NestedScrollView.OnScrollChangeListener() { @Override public void onScrollChange(NestedScrollView v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) { int dy = scrollY - oldScrollY; // 第一次调用的时候 dy = nowYOffset // 随后调用的时候可以做是变化量dy的叠加 // 在移动的过程中mBottomLayout.getTop()始终不会变 int nowYOffset = (int) (dy + mBottomLayout.getTranslationY()); Log.d("@@@", "dy = " + dy + " , nowYOffset = " + nowYOffset + " , top = " + mBottomLayout.getTop()); // scrollTo()，scrollBy()：移动view的显示位置，并不移动它的点击位置 // setTranslationX()：设置x轴平衡距离,将view的点击位置和显示位置同时移动 // 取消当前正在运行或者挂起的属性动画 ViewCompat.animate(mBottomLayout).cancel(); if (dy > 0) { // 手指向顶部移动 布局隐藏 if (nowYOffset < mBottomLayout.getHeight()) { mBottomLayout.setTranslationY(nowYOffset); } else { mBottomLayout.setTranslationY(mBottomLayout.getHeight()); } } else if (dy < 0) { // 手指向底部移动 if (nowYOffset < 0) { mBottomLayout.setTranslationY(0); } else { mBottomLayout.setTranslationY(nowYOffset); } } } }); mNestedScroller.setOnTouchListener(new View.OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_UP: case MotionEvent.ACTION_CANCEL: // positive to check scrolling down 经测试：如果已经滑动到底部时再把手指往上滑回调该方法 if (!mNestedScroller.canScrollVertically(1)) { animateHide(); return false; } // Negative to check scrolling up 经测试：如果已经滑动到顶部时再把手指往下滑回调该方法 if (!mNestedScroller.canScrollVertically(-1)) { animateShow(); return false; } if (mNestedScroller.getScrollY() <= 0) return false; if (mBottomLayout.getTranslationY() >= mBottomLayout.getHeight() / 2) { // 手指向顶部滑动 animateHide(); } else { animateShow(); } } return false; } }); } public static void delegation(NestedScrollView scroller, ViewGroup view){ new ScrollerBottomLayoutDelegation(scroller, view); } // y = top + translationY; private void animateShow(){ mBottomLayout.animate() .translationY(0) .setInterpolator(new LinearInterpolator()) .setDuration(180); } private void animateHide(){ mBottomLayout.animate() .translationY(mBottomLayout.getHeight()) .setInterpolator(new LinearInterpolator()) .setDuration(180); }}