Question

我有一个MainActivity，其中放置了Fragment。具有SearchView的片段（app：actionViewClass =＆＃34; android.support.v7.widget.SearchView＆＃34; ）和MainActivity在工具栏中有一个SearchView图标。我想隐藏/显示片段的Searchview是显示/隐藏时的工具栏中的图标（如Flipkart应用程序）。当使用Hiding或Showing方法之一时，它正常工作，但当我同时使用它们时，它会给出错误，如

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

我的代码段是......

MainActivity

 @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();
            }
        }
    });
}

Answer 1

早上好，你为什么不膨胀其他menu.xml片段？例如..在片段插入

中

@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);
}

我帮助了

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1 个答案: