Android Firebase ruft Benutzerinformationen ab, um den Zugriff zu beschränken

Question

Wie kann ich die Benutzer-Nr. "1", um in der Navigationsleiste auf 1 Registerkarte zuzugreifen. Ich habe zwei Arten von Benutzern: Benutzer 1 (Tutee) und Benutzer 2 (Tutor). Wie man es macht, wenn Benutzer 1 angemeldet ist, sehen sie in der Navigationsleiste anstelle von "Tutor-Profil" den Reiter "Bewerben für einen Tutor". Nur Benutzer 2 wird in der Lage sein, diese "Tutor Profile Tab" zu sehen und Zugriff darauf zu haben. irgendein Vorschlag?

So habe ich diese Datenstruktur auf meiner Datenbank:

{ 
     "users" : { 
      "tua3IbbJ2APuLI1z1SesBQlAGCF2" : { 
      "birthday" : "02/07/1995", 
      "country" : "Zimbabwe", 
      "email" : "email@gmail.com", 
      "hobby" : "Rugby", 
      "name" : "Ainul ", 
      "phone" : "646446", 
      "uId" : "tua3IbbJ2APuLI1z1SesBQlAGCF2", 
      "userType" : "2" 
     } 
     } 
    } 

und aus meiner HomeActivity.java:

private void setUpNavigationView() { 
    //Setting Navigation View Item Selected Listener to handle the item click of the navigation menu 
    navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() { 

     // This method will trigger on item Click of navigation menu 
     @Override 
     public boolean onNavigationItemSelected(MenuItem menuItem) { 

      //Check to see which item was being clicked and perform appropriate action 
      switch (menuItem.getItemId()) { 
       //Replacing the main content with ContentFragment Which is our Inbox View; 
       case R.id.home: 
        navItemIndex = 0; 
        CURRENT_TAG = TAG_HOME; 
        break; 
       case R.id.nav_inbox: 
        navItemIndex = 1; 
        CURRENT_TAG = TAG_INBOX; 
        break; 
       case R.id.nav_notifications: 
        navItemIndex = 2; 
        CURRENT_TAG = TAG_NOTIFICATIONS; 
        break; 
       case R.id.nav_settings: 
        navItemIndex = 3; 
        CURRENT_TAG = TAG_SETTINGS; 
        break; 
       case R.id.nav_profile: 
        // launch new intent instead of loading fragment 
        startActivity(new Intent(HomeActivity.this, ProfileActivity.class)); 
        drawer.closeDrawers(); 
        return true; 
       case R.id.nav_about_us: 
        // launch new intent instead of loading fragment 
        startActivity(new Intent(HomeActivity.this, AboutUsActivity.class)); 
        drawer.closeDrawers(); 
        return true; 
       case R.id.nav_privacy_policy: 
        // launch new intent instead of loading fragment 
        startActivity(new Intent(HomeActivity.this, PrivacyPolicyActivity.class)); 
        drawer.closeDrawers(); 
        return true; 
       default: 
        navItemIndex = 0; 
      } 

      //Checking if the item is in checked state or not, if not make it in checked state 
      if (menuItem.isChecked()) { 
       menuItem.setChecked(false); 
      } else { 
       menuItem.setChecked(true); 
      } 
      menuItem.setChecked(true); 

      loadHomeFragment(); 

      return true; 
     } 
    }); 


    ActionBarDrawerToggle actionBarDrawerToggle = new ActionBarDrawerToggle(this, drawer, toolbar, R.string.openDrawer, R.string.closeDrawer) { 

     @Override 
     public void onDrawerClosed(View drawerView) { 
      // Code here will be triggered once the drawer closes as we dont want anything to happen so we leave this blank 
      super.onDrawerClosed(drawerView); 
     } 

     @Override 
     public void onDrawerOpened(View drawerView) { 
      // Code here will be triggered once the drawer open as we dont want anything to happen so we leave this blank 
      super.onDrawerOpened(drawerView); 
     } 
    }; 

    //Setting the actionbarToggle to drawer layout 
    drawer.setDrawerListener(actionBarDrawerToggle); 

    //calling sync state is necessary or else your hamburger icon wont show up 
    actionBarDrawerToggle.syncState(); 
} 

Unten ist die vollständige Codierung von HomeActivity.java für alle Fälle im etwas fehlt :

package com.example.cqaai.tutorpal.activity; 
    import android.content.Intent; 
    import android.os.Bundle; 
    import android.os.Handler; 
    import android.support.design.widget.FloatingActionButton; 
    import android.support.design.widget.NavigationView; 
    import android.support.design.widget.Snackbar; 
    import android.support.v4.app.Fragment; 
    import android.support.v4.app.FragmentTransaction; 
    import android.support.v4.view.GravityCompat; 
    import android.support.v4.widget.DrawerLayout; 
    import android.support.v7.app.ActionBarDrawerToggle; 
    import android.support.v7.app.AppCompatActivity; 
    import android.support.v7.widget.Toolbar; 
    import android.view.Menu; 
    import android.view.MenuItem; 
    import android.view.View; 
    import android.widget.ImageView; 
    import android.widget.TextView; 
    import android.widget.Toast; 
    import android.support.annotation.NonNull; 
    import android.widget.Button; 

    import com.bumptech.glide.Glide; 
    import com.bumptech.glide.load.engine.DiskCacheStrategy; 

    import com.example.cqaai.tutorpal.R; 
    import com.example.cqaai.tutorpal.fragment.HomeFragment; 
    import com.example.cqaai.tutorpal.fragment.ProfileFragment; 
    import com.example.cqaai.tutorpal.fragment.NotificationsFragment; 
    import com.example.cqaai.tutorpal.fragment.InboxFragment; 
    import com.example.cqaai.tutorpal.fragment.SettingsFragment; 
    import com.example.cqaai.tutorpal.other.CircleTransform; 

    import com.google.firebase.auth.FirebaseAuth; 
    import com.google.firebase.auth.FirebaseUser; 

    public class HomeActivity extends AppCompatActivity { 

private NavigationView navigationView; 
private DrawerLayout drawer; 
private View navHeader; 
private ImageView imgNavHeaderBg, imgProfile; 
private TextView txtName, txtWebsite; 
private Toolbar toolbar; 
private FloatingActionButton fab; 

private Button btnSettings; 
private FirebaseAuth.AuthStateListener authListener; 
private FirebaseAuth auth; 

// urls to load navigation header background image 
// and profile image 
private static final String urlNavHeaderBg = "http://api.androidhive.info/images/nav-menu-header-bg.jpg"; 
private static final String urlProfileImg = "private static final String urlProfileImg = \"https://lh3.googleusercontent.com/eCtE_G34M9ygdkmOpYvCag1vBARCmZwnVS6rS5t4JLzJ6QgQSBquM0nuTsCpLhYbKljoyS-txg\";\n"; 

// index to identify current nav menu item 
public static int navItemIndex = 0; 

// tags used to attach the fragments 
private static final String TAG_HOME = "home"; 
private static final String TAG_PROFILE = "profile"; 
private static final String TAG_INBOX = "inbox"; 
private static final String TAG_NOTIFICATIONS = "notifications"; 
private static final String TAG_SETTINGS = "settings"; 
public static String CURRENT_TAG = TAG_HOME; 

// toolbar titles respected to selected nav menu item 
private String[] activityTitles; 

// flag to load home fragment when user presses back key 
private boolean shouldLoadHomeFragOnBackPress = true; 
private Handler mHandler; 


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

    //get firebase auth instance 
    auth = FirebaseAuth.getInstance(); 

    //get current user 
    final FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser(); 

    authListener = new FirebaseAuth.AuthStateListener() { 
     @Override 
     public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) { 
      FirebaseUser user = firebaseAuth.getCurrentUser(); 
      if (user == null) { 
       // user auth state is changed - user is null 
       // launch login activity 
       startActivity(new Intent(HomeActivity.this, LoginActivity.class)); 
       finish(); 
      } 
     } 
    }; 



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

    mHandler = new Handler(); 

    drawer = (DrawerLayout) findViewById(R.id.drawer_layout); 
    navigationView = (NavigationView) findViewById(R.id.nav_view); 
    fab = (FloatingActionButton) findViewById(R.id.fab); 

    // Navigation view header 
    navHeader = navigationView.getHeaderView(0); 
    txtName = (TextView) navHeader.findViewById(R.id.name); 
    txtWebsite = (TextView) navHeader.findViewById(R.id.website); 
    imgNavHeaderBg = (ImageView) navHeader.findViewById(R.id.img_header_bg); 
    imgProfile = (ImageView) navHeader.findViewById(R.id.img_profile); 

    // load toolbar titles from string resources 
    activityTitles = getResources().getStringArray(R.array.nav_item_activity_titles); 

    fab.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View view) { 
      Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG) 
        .setAction("Action", null).show(); 
     } 
    }); 

    // load nav menu header data 
    loadNavHeader(); 

    // initializing navigation menu 
    setUpNavigationView(); 

    if (savedInstanceState == null) { 
     navItemIndex = 0; 
     CURRENT_TAG = TAG_HOME; 
     loadHomeFragment(); 
    } 
} 

/*** 
* Load navigation menu header information 
* like background image, profile image 
* name, website, notifications action view (dot) 
*/ 



private void loadNavHeader() { 
    // name, website 
    txtName.setText("Ainul Fitiri"); 
    txtWebsite.setText("@ainulfi3"); 

    // loading header background image 
    Glide.with(this).load(urlNavHeaderBg) 
      .crossFade() 
      .diskCacheStrategy(DiskCacheStrategy.ALL) 
      .into(imgNavHeaderBg); 

    // Loading profile image 
    Glide.with(this).load(urlProfileImg) 
      .crossFade() 
      .thumbnail(0.5f) 
      .bitmapTransform(new CircleTransform(this)) 
      .diskCacheStrategy(DiskCacheStrategy.ALL) 
      .into(imgProfile); 

    // showing dot next to notifications label 
    navigationView.getMenu().getItem(3).setActionView(R.layout.menu_dot); 
} 

/*** 
* Returns respected fragment that user 
* selected from navigation menu 
*/ 
private void loadHomeFragment() { 
    // selecting appropriate nav menu item 
    selectNavMenu(); 

    // set toolbar title 
    setToolbarTitle(); 

    // if user select the current navigation menu again, don't do anything 
    // just close the navigation drawer 
    if (getSupportFragmentManager().findFragmentByTag(CURRENT_TAG) != null) { 
     drawer.closeDrawers(); 

     // show or hide the fab button 
     toggleFab(); 
     return; 
    } 

    // Sometimes, when fragment has huge data, screen seems hanging 
    // when switching between navigation menus 
    // So using runnable, the fragment is loaded with cross fade effect 
    // This effect can be seen in GMail app 
    Runnable mPendingRunnable = new Runnable() { 
     @Override 
     public void run() { 
      // update the main content by replacing fragments 
      Fragment fragment = getHomeFragment(); 
      FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction(); 
      fragmentTransaction.setCustomAnimations(android.R.anim.fade_in, 
        android.R.anim.fade_out); 
      fragmentTransaction.replace(R.id.frame, fragment, CURRENT_TAG); 
      fragmentTransaction.commitAllowingStateLoss(); 
     } 
    }; 

    // If mPendingRunnable is not null, then add to the message queue 
    if (mPendingRunnable != null) { 
     mHandler.post(mPendingRunnable); 
    } 

    // show or hide the fab button 
    toggleFab(); 

    //Closing drawer on item click 
    drawer.closeDrawers(); 

    // refresh toolbar menu 
    invalidateOptionsMenu(); 
} 

private Fragment getHomeFragment() { 
    switch (navItemIndex) { 
     case 0: 
      // home 
      HomeFragment homeFragment = new HomeFragment(); 
      return homeFragment; 
     case 1: 
      // Inbox fragment 
      InboxFragment inboxFragment = new InboxFragment(); 
      return inboxFragment; 
     case 2: 
      // notifications fragment 
      NotificationsFragment notificationsFragment = new NotificationsFragment(); 
      return notificationsFragment; 

     case 3: 
      // settings fragment 
      SettingsFragment settingsFragment = new SettingsFragment(); 
      return settingsFragment; 
     default: 
      return new HomeFragment(); 
    } 
} 

private void setToolbarTitle() { 
    getSupportActionBar().setTitle(activityTitles[navItemIndex]); 
} 

private void selectNavMenu() { 
    navigationView.getMenu().getItem(navItemIndex).setChecked(true); 
} 

private void setUpNavigationView() { 
    //Setting Navigation View Item Selected Listener to handle the item click of the navigation menu 
    navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() { 

     // This method will trigger on item Click of navigation menu 
     @Override 
     public boolean onNavigationItemSelected(MenuItem menuItem) { 

      //Check to see which item was being clicked and perform appropriate action 
      switch (menuItem.getItemId()) { 
       //Replacing the main content with ContentFragment Which is our Inbox View; 
       case R.id.home: 
        navItemIndex = 0; 
        CURRENT_TAG = TAG_HOME; 
        break; 
       case R.id.nav_profile: 
        navItemIndex = 1; 
        CURRENT_TAG = TAG_PROFILE; 
        break; 
       case R.id.nav_inbox: 
        navItemIndex = 1; 
        CURRENT_TAG = TAG_INBOX; 
        break; 
       case R.id.nav_notifications: 
        navItemIndex = 2; 
        CURRENT_TAG = TAG_NOTIFICATIONS; 
        break; 
       case R.id.nav_settings: 
        navItemIndex = 3; 
        CURRENT_TAG = TAG_SETTINGS; 
        break; 
       case R.id.nav_profile: 
        // launch new intent instead of loading fragment 
        startActivity(new Intent(HomeActivity.this, ProfileActivity.class)); 
        drawer.closeDrawers(); 
        return true; 
       case R.id.nav_about_us: 
        // launch new intent instead of loading fragment 
        startActivity(new Intent(HomeActivity.this, AboutUsActivity.class)); 
        drawer.closeDrawers(); 
        return true; 
       case R.id.nav_privacy_policy: 
        // launch new intent instead of loading fragment 
        startActivity(new Intent(HomeActivity.this, PrivacyPolicyActivity.class)); 
        drawer.closeDrawers(); 
        return true; 
       default: 
        navItemIndex = 0; 
      } 

      //Checking if the item is in checked state or not, if not make it in checked state 
      if (menuItem.isChecked()) { 
       menuItem.setChecked(false); 
      } else { 
       menuItem.setChecked(true); 
      } 
      menuItem.setChecked(true); 

      loadHomeFragment(); 

      return true; 
     } 
    }); 


    ActionBarDrawerToggle actionBarDrawerToggle = new ActionBarDrawerToggle(this, drawer, toolbar, R.string.openDrawer, R.string.closeDrawer) { 

     @Override 
     public void onDrawerClosed(View drawerView) { 
      // Code here will be triggered once the drawer closes as we dont want anything to happen so we leave this blank 
      super.onDrawerClosed(drawerView); 
     } 

     @Override 
     public void onDrawerOpened(View drawerView) { 
      // Code here will be triggered once the drawer open as we dont want anything to happen so we leave this blank 
      super.onDrawerOpened(drawerView); 
     } 
    }; 

    //Setting the actionbarToggle to drawer layout 
    drawer.setDrawerListener(actionBarDrawerToggle); 

    //calling sync state is necessary or else your hamburger icon wont show up 
    actionBarDrawerToggle.syncState(); 
} 

@Override 
public void onBackPressed() { 
    if (drawer.isDrawerOpen(GravityCompat.START)) { 
     drawer.closeDrawers(); 
     return; 
    } 

    // This code loads home fragment when back key is pressed 
    // when user is in other fragment than home 
    if (shouldLoadHomeFragOnBackPress) { 
     // checking if user is on other navigation menu 
     // rather than home 
     if (navItemIndex != 0) { 
      navItemIndex = 0; 
      CURRENT_TAG = TAG_HOME; 
      loadHomeFragment(); 
      return; 
     } 


    } 

    super.onBackPressed(); 
} 

@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    // Inflate the menu; this adds items to the action bar if it is present. 

    // show menu only when home fragment is selected 
    if (navItemIndex == 0) { 
     getMenuInflater().inflate(R.menu.main, menu); 

    } 

    // when fragment is notifications, load the menu created for notifications 
    if (navItemIndex == 3) { 
     getMenuInflater().inflate(R.menu.notifications, menu); 
    } 
    return true; 
} 



@Override 
public boolean onOptionsItemSelected(MenuItem item) { 
    // Handle action bar item clicks here. The action bar will 
    // automatically handle clicks on the Home/Up button, so long 
    // as you specify a parent activity in AndroidManifest.xml. 
    int id = item.getItemId(); 

    //noinspection SimplifiableIfStatement 
    if (id == R.id.action_logout) { 
     //signing out user 
     auth.signOut(); 
     Intent intent = new Intent(HomeActivity.this, LoginActivity.class); 
     startActivity(intent); 

     Toast.makeText(getApplicationContext(), "Logout user!", Toast.LENGTH_LONG).show(); 
     return true; 
    } 

    // user is in notifications fragment 
    // and selected 'Mark all as Read' 
    if (id == R.id.action_mark_all_read) { 
     Toast.makeText(getApplicationContext(), "All notifications marked as read!", Toast.LENGTH_LONG).show(); 
    } 

    // user is in notifications fragment 
    // and selected 'Clear All' 
    if (id == R.id.action_clear_notifications) { 
     Toast.makeText(getApplicationContext(), "Clear all notifications!", Toast.LENGTH_LONG).show(); 
    } 

    return super.onOptionsItemSelected(item); 
} 

// show or hide the fab 
private void toggleFab() { 
    if (navItemIndex == 0) 
     fab.show(); 
    else 
     fab.hide(); 
} 

}

Answer 1

Eine Möglichkeit, dies zu erreichen, ist die Verwendung von SharedPreferences. Sie können also einfach den userType speichern und entweder Typ 1 (Tutee) oder Typ 2 (Tutor) prüfen.

Zuerst müssen Sie die usertype des angemeldeten Benutzers zu erhalten, so dass dies gehen könnte in Ihnen Bildschirm einloggen:

databaseReference.addValueEventListener(new ValueEventListener() { 
    @Override 
    public void onDataChange(DataSnapshot dataSnapshot) { 

     String userType = dataSnapshot.child("users").child(task.getResult().getUser().getUid()).getValue(User.class).getUId(); 

     SharedPreferences sharedPreferences = getSharedPreferences("prefs", MODE_PRIVATE); 
     SharedPreferences.Editor editor = sharedPreferences.edit(); 
     editor.putString("userType", userType); 
     editor.commit();     

    } 

    @Override 
    public void onCancelled(DatabaseError databaseError) { 
     // NO-OP 
    } 
}); 

Die Benutzerklasse sollten Sie Benutzer POJO sein oder was auch immer Klasse, die Sie in Ihrem Modell haben für der Benutzer.

Jetzt können Sie die usertype von Ihrem SharedPreferences, abrufen und eine Bedingung entweder verbergen gesetzt oder die Artikel in Ihrem NavigationView-Menü zeigen:

SharedPreferences sharedPreferences = getSharedPreferences("prefs", MODE_PRIVATE); 
if (sharedPreferences.getString("userType", 1).equals("1")) { 
    navigationView.getMenu().findItem(R.id.ITEM_ID).setVisible(false); 
} else { 
    navigationView.getMenu().findItem(R.id.ITEM_ID).setVisible(true); 
} 

Der obige Code in Ihre setUpNavigationView() -Methode gehen sollte. Und wenn Sie möchten, die Einstellungen deaktivieren, wenn sich der Benutzer abmeldet mit:

editor.clear(); 
editor.commit(); 

this helps;)