打开某个片段时如何隐藏导航抽屉？

Question

I'm pretty new in android development. I want to hide navigation drawer when user is not logged in. So basically, it will shown login fragment (better in full screen like Facebook android). And if user already logged in, navigation drawer will always shown.

MainActivity.java

public class MainActivity extends AppCompatActivity {

private DrawerLayout navDrawerLayout;
private Toolbar toolbar;
private ActionBarDrawerToggle navDrawerToggle;

private SharedPreferences pref;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    navDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);

    // Find our drawer view
    NavigationView navDrawerView = (NavigationView) findViewById(R.id.navdrawer_view);
    // Setup drawer view
    setupDrawerContent(navDrawerView);

    navDrawerToggle = setupDrawerToggle();

    pref = getPreferences(0);
    initFirstFrame();
}

private ActionBarDrawerToggle setupDrawerToggle() {
    return new ActionBarDrawerToggle(this, navDrawerLayout, toolbar, R.string.drawer_open,  R.string.drawer_close);
}

private void setupDrawerContent(NavigationView navDrawerView) {
    navDrawerView.setNavigationItemSelectedListener(
            new NavigationView.OnNavigationItemSelectedListener() {
                @Override
                public boolean onNavigationItemSelected(MenuItem menuItem) {
                    selectDrawerItem(menuItem);
                    return true;
                }


            });
}

public void selectDrawerItem(MenuItem menuItem) {
    // Create a new fragment and specify the fragment to show based on nav item clicked
    Fragment fragment = null;
    Class fragmentClass;
    switch(menuItem.getItemId()) {
        case R.id.events:
            fragmentClass = EventsFragment.class;
            break;
        case R.id.pengumuman:
            fragmentClass = NewsFragment.class;
            break;
        case R.id.edit_profil:
            fragmentClass = ProfileFragment.class;
            break;
        default:
            fragmentClass = EventsFragment.class;
    }

    try {
        fragment = (Fragment) fragmentClass.newInstance();
    } catch (Exception e) {
        e.printStackTrace();
    }

    // Insert the fragment by replacing any existing fragment
    FragmentManager fragmentManager = getSupportFragmentManager();
    fragmentManager.beginTransaction().replace(R.id.frame_content, fragment).commit();

    // Highlight the selected item has been done by NavigationView
    menuItem.setChecked(true);
    // Set action bar title
    setTitle(menuItem.getTitle());
    // Close the navigation drawer
    navDrawerLayout.closeDrawers();
}

private void initFirstFrame(){
    Fragment fragment;
    if(pref.getBoolean(Constants.IS_LOGGED_IN,false)){
        fragment = new ProfileFragment();
    }else {
        fragment = new LoginFragment();
        // in this login fragment, navdrawer should be invisible, the toolbar too I guess
    }

    FragmentManager fragmentManager = getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    fragmentTransaction.replace(R.id.frame_content,fragment);
    fragmentTransaction.commit();
}


@Override
public boolean onOptionsItemSelected(MenuItem item) {
    return navDrawerToggle.onOptionsItemSelected(item) || super.onOptionsItemSelected(item);
}

// 'onPostCreate' called when activity start-up is complete after 'onStart()'
// NOTE! Make sure to override the method with only a single 'Bundle' argument
@Override
protected void onPostCreate(Bundle savedInstanceState) {
    super.onPostCreate(savedInstanceState);
    // Sync the toggle state after onRestoreInstanceState has occurred
    navDrawerToggle.syncState();
}

@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
    // Pass any configuration change to the drawer toggles
    navDrawerToggle.onConfigurationChanged(newConfig);
}

}

Answer 1

Define an interface say DrawerLocker:

interface DrawerLocker{
   public void setDrawerLocked(boolean shouldLock);
}

Implement this interface in your activity which contains the NavigationDrawer and override this method.

class YourActivity implements DrawerLocker{
...
...
public void setDrawerLocked(boolean enabled){
    if(enabled){
        drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);
    }else{
        drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);
    }

}

Now in your Fragment's onCreateView, call this method like:

 ((DrawerLocker)getActivity()).setDrawerLocked(true);

In your Fragment's onDestroyView, re enable the drawer layout:

((DrawerLocker)getActivity()).setDrawerLocked(false);

Answer 2

This code in activity onCreate method will block drawer when you will have more than one fragment in stack:

 getSupportFragmentManager().addOnBackStackChangedListener(() -> {
        if (getSupportFragmentManager().getBackStackEntryCount() > 0) {
drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);
        } else {
            drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);
        }
    });

Answer 3

This is all you need, check your destinations in if condition where you don't want the drawer to be

Single activity architecture, put below code in activity onCreate

private fun changeDrawerState() {
    val navHostFragment = supportFragmentManager
        .findFragmentById(R.id.nav_host_fragment) as NavHostFragment
    val drawer = findViewById<DrawerLayout>(R.id.drawer_layout)
    navHostFragment.navController.addOnDestinationChangedListener(listener = { _, destination, _ ->
        //set in case app asked for verify auth, signIn page drawer will be locked
        if (destination.id== R.id.signInFragment) {
            drawer.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED)
        } else if (drawer.getDrawerLockMode(GravityCompat.START) != DrawerLayout.LOCK_MODE_UNLOCKED) {
            drawer.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED)
        }
    })
}

GravityCompat.START based on your drawer open direction