android一个向上滑动显示菜单，向下滑动隐藏菜单实现

 最近发现浏览器qq猎豹等，很多都是，向上滑动显示搜索菜单，向下浏览网页隐藏搜索菜单，而且非常平滑的效果，用Visistty.setVisisty(View....)一直达到我想要的效果。用改变view的位置，平移到屏幕显示外面。并且带有动画效果来实现。貌似会更好点。直接看代码。一部分代码仿另一个开源项目基础上修改而来的。

 
主要原理是检查判定是否在滑动到屏幕的顶部或者底部，根据其顶部的话就，让我们的内容view 偏移顶部高度为我们topview高度，否则view偏移量为0。并为其设置平移动画效果。 

 

public class ScrollViewActivity extends Activity {

    private PoppyViewHelper mPoppyViewHelper;

    private LayoutInflater layoutInflater;

    private NotifyingScrollView scrollView;

    private View poppyview;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_scrollview);

        layoutInflater=LayoutInflater.from(this);

        scrollView=(NotifyingScrollView)findViewById(R.id.scrollView);

        poppyview=layoutInflater.inflate(R.layout.poppyview, null);

        

        

        mPoppyViewHelper = new PoppyViewHelper(this, PoppyViewPosition.TOP);

        ViewGroup poppyView = mPoppyViewHelper.createPoppyViewOnScrollView(scrollView, poppyview);

        

        poppyView.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                Toast.makeText(ScrollViewActivity.this, "Click me!", Toast.LENGTH_SHORT).show();

            }

        });

    }

}

 

 

public class PoppyViewHelper {

    public enum PoppyViewPosition {

        TOP, BOTTOM

    };

    private static final int SCROLL_TO_TOP = - 1;

    private static final int SCROLL_TO_BOTTOM = 1;

    private static final int SCROLL_DIRECTION_CHANGE_THRESHOLD = 5;

    private Activity mActivity;

    private LayoutInflater mLayoutInflater;

    private View mPoppyView;

    private int mScrollDirection = 0;

    private int mPoppyViewHeight = - 1;

    

    private PoppyViewPosition mPoppyViewPosition;

    public PoppyViewHelper(Activity activity, PoppyViewPosition position) {

        mActivity = activity;

        mLayoutInflater = LayoutInflater.from(activity);

        mPoppyViewPosition = position;

    }

    public PoppyViewHelper(Activity activity) {

        this(activity, PoppyViewPosition.BOTTOM);

    }

    

    private ViewGroup viewGroup;

    // for scrollview

    private  NotifyingScrollView scrollView;

    public ViewGroup createPoppyViewOnScrollView(NotifyingScrollView scrollViewId, View poppyViewResId) {

         mPoppyView =poppyViewResId;

         scrollView = scrollViewId;

        initPoppyViewOnScrollView();

        return viewGroup;

    }

    // for ListView

    public View createPoppyViewOnListView(int listViewId, int poppyViewResId, OnScrollListener onScrollListener) {

        final ListView listView = (ListView)mActivity.findViewById(listViewId);

        if(listView.getHeaderViewsCount() != 0) {

            throw new IllegalArgumentException("use createPoppyViewOnListView with headerResId parameter");

        }

        if(listView.getFooterViewsCount() != 0) {

            throw new IllegalArgumentException("poppyview library doesn't support listview with footer");

        }

        mPoppyView = mLayoutInflater.inflate(poppyViewResId, null);

        initPoppyViewOnListView(listView, onScrollListener);

        return mPoppyView;

    }

    public View createPoppyViewOnListView(int listViewId, int poppyViewResId) {

        return createPoppyViewOnListView(listViewId, poppyViewResId, null);

    }

    // common

    private void setPoppyViewOnView(View view) {

        LayoutParams lp = view.getLayoutParams();

        ViewParent parent = view.getParent();

        ViewGroup group = (ViewGroup)parent;

        int index = group.indexOfChild(view);

        final FrameLayout newContainer = new FrameLayout(mActivity);

        group.removeView(view);

        group.addView(newContainer, index, lp);

        newContainer.addView(view);

        final FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);

        layoutParams.gravity = mPoppyViewPosition == PoppyViewPosition.BOTTOM ? Gravity.BOTTOM : Gravity.TOP;

        newContainer.addView(mPoppyView, layoutParams);

        group.invalidate();

        viewGroup=group;

    }

    private boolean isjixu=false;

    private void onScrollPositionChanged(int oldScrollPosition, int newScrollPosition) {

        int newScrollDirection;

        System.out.println(oldScrollPosition + " ->" + newScrollPosition);

        if(newScrollPosition < oldScrollPosition) {

            newScrollDirection = SCROLL_TO_TOP;

            isjixu=true;

            //gundong滚动dao到dingb顶部

        } else {

            newScrollDirection = SCROLL_TO_BOTTOM;

            isjixu=false;

        }

        if(newScrollDirection != mScrollDirection) {

            mScrollDirection = newScrollDirection;

            translateYPoppyView();

        }

    }

    private     int translationY = 0;

    private boolean isdingbu=false;

    private void translateYPoppyView() {

    

        mPoppyView.post(new Runnable() {

            @Override

            public void run() {

                if(mPoppyViewHeight <= 0) {

                    mPoppyViewHeight = mPoppyView.getHeight();

                }

                

                

                switch (mPoppyViewPosition) {

                case BOTTOM:

                    translationY = mScrollDirection == SCROLL_TO_TOP ? 0 : mPoppyViewHeight;

                    

                    break;

                case TOP:

                    translationY = mScrollDirection == SCROLL_TO_TOP ?  0:  -mPoppyViewHeight;

                    isdingbu=true;

                    break;

                }

                ViewPropertyAnimator.animate(mPoppyView).setDuration(300).translationY(translationY);

            }

        });

        if(isdingbu){

            scrollView.post(new Runnable() {

                @Override

                public void run() {

                    如果为顶部显示就让view平移Mpoppyviewhiegh高度

                    ViewPropertyAnimator.animate(scrollView).setDuration(300).translationY(mPoppyViewHeight);

                    isdingbu=false;

                }

            });

            

        }else{

            scrollView.post(new Runnable() {

                @Override

                public void run() {

                    不然就让他显示在屏幕顶部

                    ViewPropertyAnimator.animate(scrollView).setDuration(300).translationY(0);

                }

            });

            

        }

        

    }

    // for ScrollView

    private void initPoppyViewOnScrollView() {

        setPoppyViewOnView(scrollView);

        scrollView.setOnScrollChangedListener(new NotifyingScrollView.OnScrollChangedListener() {

            int mScrollPosition;

            public void onScrollChanged(ScrollView who, int l, int t, int oldl, int oldt) {

                if(Math.abs(t - mScrollPosition) >= SCROLL_DIRECTION_CHANGE_THRESHOLD) {

                    onScrollPositionChanged(mScrollPosition, t);

                }

                

                mScrollPosition = t;

            }

        });

    }

    // for ListView

    private void initPoppyViewOnListView(ListView listView, final OnScrollListener onScrollListener) {

        setPoppyViewOnView(listView);

        listView.setOnScrollListener(new OnScrollListener() {

            int mScrollPosition;

            @Override

            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {

                if(onScrollListener != null) {

                    onScrollListener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);

                }

                View topChild = view.getChildAt(0);

                int newScrollPosition = 0;

                if(topChild == null) {

                    newScrollPosition = 0;

                } else {

                    newScrollPosition = - topChild.getTop() + view.getFirstVisiblePosition() * topChild.getHeight();

                }

                if(Math.abs(newScrollPosition - mScrollPosition) >= SCROLL_DIRECTION_CHANGE_THRESHOLD) {

                    onScrollPositionChanged(mScrollPosition, newScrollPosition);

                }

                mScrollPosition = newScrollPosition;

            }

            @Override

            public void onScrollStateChanged(AbsListView view, int scrollState) {

                if(onScrollListener != null) {

                    onScrollListener.onScrollStateChanged(view, scrollState);

                }

            }

        });

    }

}