[英]Navigation Menu Fragment not being able to initialize its layout's components
我為我的應用程序創建了一個導航菜單片段,以便我可以在我的所有活動中使用它。 但是,當我運行應用程序時,菜單不會在我點擊漢堡包圖標時也不會工作,也不會在我從左向右拉動時。 所以我決定使用調試器,我發現我的片段的布局組件都沒有在片段的類中初始化。 你能幫我弄清楚為什么會發生這種情況以及如何解決這個問題嗎? 這是我的fragment.java類和我的fragment_layout.xml文件:
Fragment.java:
public class NavMenuFragment extends Fragment {
// NavMenu member vars
private DrawerLayout mDrawerLayout;
private NavigationView navigationView;
private ActionBarDrawerToggle mToggle; // Button for toggling the side menu
// Keeps the position of the previously selected menu item(0 : Home)
int position = 0;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_nav_menu,null);
mDrawerLayout = view.findViewById(R.id.drawerLayout);
navigationView = view.findViewById(R.id.nav_view);
mToggle = new ActionBarDrawerToggle(getActivity(),mDrawerLayout,R.string.drawer_open,R.string.drawer_closed); // Instantiating our button
return view;
}
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// Sets the default selected menu item, to the Home item
navigationView.getMenu().findItem(R.id.nav_home).setChecked(true);
// Used to help on check and uncheck menu items when the user clicks on them
final List<MenuItem> items = new ArrayList<>();
Menu menu;
menu = navigationView.getMenu();
// Fill the list with all the menu items
for(int i=0; i<menu.size();i++) {
items.add(menu.getItem(i));
}
Toast.makeText(getActivity(), "size:" + items.size(), Toast.LENGTH_SHORT).show();
// When an item inside the NavView gets clicked, then handle the event...
navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.nav_home:
mDrawerLayout.closeDrawer(Gravity.START);
break;
case R.id.nav_UserBoxGLB:
break;
case R.id.nav_UserBoxJP:
break;
case R.id.nav_settings:
break;
case R.id.nav_feedback:
break;
case R.id.nav_contact_us:
break;
case R.id.nav_donate:
// Open the website's URL in a browser window
Intent intent = new Intent();
intent.setAction(Intent.ACTION_VIEW);
intent.addCategory(Intent.CATEGORY_BROWSABLE);
intent.setData(Uri.parse("http://www.google.com"));
startActivity(intent);
break;
case R.id.nav_about:
break;
default:
return onNavigationItemSelected(item);
}
items.get(position).setChecked(false);
item.setChecked(true);
mDrawerLayout.closeDrawers();
return false;
}
});
mDrawerLayout.addDrawerListener(mToggle);
// Set the hamburger icon's color
mToggle.getDrawerArrowDrawable().setColor(getResources().getColor(R.color.NavActionBarTextColor));
mToggle.syncState();
}
// When an item from the Action Bar gets tapped, then...
@Override
public boolean onOptionsItemSelected(MenuItem item) {
return mToggle.onOptionsItemSelected(item) || onOptionsItemSelected(item);
}
}
Fragment_layout.xml:
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_gravity="left"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/colorPrimary"
android:id="@+id/drawerLayout">
<!-- The actual side menu Nav View -->
<android.support.design.widget.NavigationView
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
app:headerLayout="@layout/navigation_header"
app:menu="@menu/navigation_menu"
android:id="@+id/nav_view">
</android.support.design.widget.NavigationView>
</android.support.v4.widget.DrawerLayout>
你做錯了
如果你想為所有片段使用相同的導航抽屜
您可以在主活動中創建導航抽屜,並從該導航抽屜中打開片段。
這是教程
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