Android 向上滚动隐藏视图和向下滚动显示视图效果，如 twitter

Question

如何在向上滚动隐藏viewpager选项卡（主页，发现，活动）时做类似twitter的滚动效果。或类似 facebook 滚动的效果，而向上滚动隐藏选项视图（状态、照片、签到）时，向下滚动显示选项视图。任何示例链接都可以，请提供帮助。

Answer 1

简单的解决方案：

public abstract class OnScrollObserver implements AbsListView.OnScrollListener {

public abstract void onScrollUp();

public abstract void onScrollDown();

@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}

int last = 0;
boolean control = true;

@Override
public void onScroll(AbsListView view, int current, int visibles, int total) {
    if (current < last && !control) {
        onScrollUp();
        control = true;
    } else if (current > last && control) {
        onScrollDown();
        control = false;
    }

    last = current;
}

用法：

listView.setOnScrollListener(new OnScrollObserver() {
        @Override
        public void onScrollUp() {

        }

        @Override
        public void onScrollDown() {

        }
    });

Answer 2

编辑：更好，你有这个库https://github.com/ksoichiro/Android-ObservableScrollView

你可以看看这个https://github.com/LarsWerkman/QuickReturnListView

来源：https://stackoverflow.com/a/25304575/244702

Answer 3

这是我自己的实现： 注意：

• 要隐藏的视图应该是固定高度
• 我们没有隐藏 Visiblity.GONE 的视图
• 我们将最终高度设置为 0px

代码如下：

    //Your view which you would like to animate
    final RelativeLayout yourViewToHide = (yourViewToHideativeLayout) findViewById(R.id.topWrapper);
    //The initial height of that view
    final int initialViewHeight = yourViewToHide.getLayoutParams().height;
    listView.setOnScrollListener(new AbsListView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(AbsListView view, int scrollState) {

        }

        @Override
        public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
            //Try catch block for NullPointerExceptions
            try{
                //Here is a simple delay. If user scrolls ListView from the top of the screen to the bottom then continue
                if(firstVisibleItem % visibleItemCount == 0) {
                    //Here we initialize the animator, doesn't matter what values You will type in
                    ValueAnimator animator = ValueAnimator.ofInt(0, 1);
                    //if Scrolling up
                    if (fastScrollSB.getProgress() > view.getFirstVisiblePosition()){
                        //Getting actual yourViewToHide params
                        ViewGroup.LayoutParams params = yourViewToHide.getLayoutParams();
                        if (!animator.isRunning()) {
                            //Setting animation from actual value to the initial yourViewToHide height)
                            animator.setIntValues(params.height, initialViewHeight);
                            //Animation duration
                            animator.setDuration(500);
                            //In this listener we update the view
                            animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                                @Override
                                public void onAnimationUpdate(ValueAnimator animation) {
                                    ViewGroup.LayoutParams params = yourViewToHide.getLayoutParams();
                                    params.height = (int) animation.getAnimatedValue();
                                    yourViewToHide.setLayoutParams(params);
                                }
                            });
                            //Starting the animation
                            animator.start();

                        }
                        System.out.println("Scrolling up!");
                    //If not scrolling
                    } else if (fastScrollSB.getProgress() == view.getFirstVisiblePosition()) {

                        System.out.println("Not Scrolling!");
                    //If scrolling down
                    } else if (fastScrollSB.getProgress() < view.getFirstVisiblePosition()){
                        //Getting actual yourViewToHide params
                        ViewGroup.LayoutParams params = yourViewToHide.getLayoutParams();
                        if (!animator.isRunning()) {
                            //Setting animation from actual value to the target value (here 0, because we're hiding the view)
                            animator.setIntValues(params.height, 0);
                            //Animation duration
                            animator.setDuration(500);
                            //In this listener we update the view
                            animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                                @Override
                                public void onAnimationUpdate(ValueAnimator animation) {
                                    ViewGroup.LayoutParams params = yourViewToHide.getLayoutParams();
                                    params.height = (int) animation.getAnimatedValue();
                                    yourViewToHide.setLayoutParams(params);
                                }
                            });
                            //Starting the animation
                            animator.start();

                        }
                        System.out.println("Scrolling down!");

                    }
                }
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    });`

希望它符合您的需求:)

Answer 4

这方面没有简单的例子。但是您可以做的是跟踪您滚动的方式并相应地显示或隐藏视图

例如，获取 ListView 的第一个可见位置来跟踪它，如果它更小，那么在你知道你正在向上滚动之前，你可以显示视图。如果它更大，则隐藏视图。

这是一种简单的方法，以防您想要更精确地使用 onTouchListeners 和运动的 y 坐标。

http://developer.android.com/reference/android/widget/ListView.html