Android 搜索操作菜单图标未隐藏

我有一个放置碎片的主要活动。具有SearchView的片段（app:actionViewClass=“android.support.v7.widget.SearchView” )MainActivity在工具栏中有一个SearchView图标。 当片段的Searchview为show/hide（如Flipkart应用程序）时，我想从工具栏隐藏/显示图标。当使用隐藏或显示方法中的一种时，它工作正常，但当我同时使用这两种方法时，它会产生如下错误

java.lang.NullPointerException: Attempt to invoke interface method 'android.view.MenuItem android.view.Menu.findItem(int)' on a null object reference

我的代码片段是

main活动

 @Override
public boolean onCreateOptionsMenu(final Menu menu)
{
    _menu = menu;
    final Menu m= menu;
    getMenuInflater().inflate(R.menu.menus, menu);
    final MenuItem searchItem = menu.findItem(R.id.action_search);

    SearchManager searchManager = (SearchManager) DrawerActivity.this.getSystemService(Context.SEARCH_SERVICE);

    SearchView searchView = null;
    if (searchItem != null) {
        searchView = (SearchView) MenuItemCompat.getActionView(searchItem);
    }
    if (searchView != null) {
        searchView.setSearchableInfo(searchManager.getSearchableInfo(getComponentName()));
    }
    searchView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            m.performIdentifierAction(searchItem.getItemId(), 0);
        }
    });

    searchItem.setVisible(false);
    return super.onCreateOptionsMenu(menu);
}

public void show_search(){

    final MenuItem searchItem = _menu.findItem(R.id.action_search);
    searchItem.setVisible(true);
//        invalidateOptionsMenu();  //if i use this it not show the icon.
}

public void hide_search() {
    final MenuItem sitem = _menu.findItem(R.id.action_search); // gives NullPointerException in this line.
    sitem.setVisible(false);
    invalidateOptionsMenu();
}

片段代码：

public class Fragment1 extends Fragment
{

         scroll = (ScrollView) v.findViewById(R.id.scroll_view);

// Total Height of layout which contains searchview
    ViewTreeObserver vas = lin.getViewTreeObserver();
    vas.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            ViewGroup.MarginLayoutParams vlp = (ViewGroup.MarginLayoutParams) lin.getLayoutParams();
            search_size = lin.getMeasuredHeight() + vlp.topMargin;
            lin.getViewTreeObserver().removeGlobalOnLayoutListener(this);

        }
    });
         scroll.getViewTreeObserver().addOnScrollChangedListener(new ViewTreeObserver.OnScrollChangedListener() {

        @Override
        public void onScrollChanged() {

            float y = scroll.getScrollY();

            DrawerActivity d = (DrawerActivity) getActivity();
            if (y >= search_size)
            {
                d.show_search();
            }
            else
            {
                d.hide_search();
            }
        }
    });
}

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早上好，为什么不将其他menu.xml文件的片段放大？ 例如在你的片段中插入

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    setHasOptionsMenu(true);
}

private Menu mMenu;
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    inflater.inflate(R.menu.menu_fragment, menu);
    mMenu = menu;

    MenuItem searchViewItem = menu.findItem(R.id.search);

    final android.support.v7.widget.SearchView searchView =
            (android.support.v7.widget.SearchView) MenuItemCompat.getActionView(searchViewItem);

    super.onCreateOptionsMenu(menu, inflater);
}

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我已经帮了你

没有，你只要试试flipkart应用程序，我只想在滚动时隐藏/显示工具栏中的搜索图标。