Merge pull request #74 from wncc/back-navigation

Implement back navigation

app/src/main/java/in/ac/iitb/gymkhana/iitbapp/MainActivity.java

@@ -15,6 +15,7 @@ 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.util.Log;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
@@ -47,8 +48,7 @@ import static in.ac.iitb.gymkhana.iitbapp.Constants.MY_PERMISSIONS_REQUEST_READ_
 import static in.ac.iitb.gymkhana.iitbapp.Constants.RESULT_LOAD_IMAGE;
 
 
-public class MainActivity extends AppCompatActivity
-        implements NavigationView.OnNavigationItemSelectedListener {
+public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
 
 
     private static final String TAG = "MainActivity";
@@ -56,6 +56,7 @@ public class MainActivity extends AppCompatActivity
     NotificationsResponse notificationsResponse;
     private User currentUser;
     private boolean showNotifications = false;
+    FeedFragment feedFragment;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -74,7 +75,7 @@ public class MainActivity extends AppCompatActivity
         drawer.addDrawerListener(toggle);
         toggle.syncState();
 
-        FeedFragment feedFragment = new FeedFragment();
+        feedFragment = new FeedFragment();
         updateFragment(feedFragment);
 
 //        fetchNotifications();
@@ -150,6 +151,8 @@ public class MainActivity extends AppCompatActivity
         DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
         if (drawer.isDrawerOpen(GravityCompat.START)) {
             drawer.closeDrawer(GravityCompat.START);
+        } else if (feedFragment != null && feedFragment.isVisible()) {
+            finish();
         } else {
             super.onBackPressed();
         }
@@ -187,7 +190,7 @@ public class MainActivity extends AppCompatActivity
 
         switch (id) {
             case R.id.nav_feed:
-                FeedFragment feedFragment = new FeedFragment();
+                feedFragment = new FeedFragment();
                 updateFragment(feedFragment);
                 break;
             case R.id.nav_my_events:
@@ -249,14 +252,20 @@ public class MainActivity extends AppCompatActivity
         return true;
     }
 
-    private void updateFragment(Fragment fragment) {
-        Bundle bundle = new Bundle();
-        bundle.putString(Constants.SESSION_ID, session.pref.getString(Constants.SESSION_ID, "Error"));
+    public void updateFragment(Fragment fragment) {
+        Log.d(TAG, "updateFragment: " + fragment.toString());
+        Bundle bundle = fragment.getArguments();
+        if (bundle == null) {
+            bundle = new Bundle();
+        }
+        bundle.putString(SESSION_ID, session.pref.getString(SESSION_ID, "Error"));
         fragment.setArguments(bundle);
         FragmentManager manager = getSupportFragmentManager();
+        if (fragment instanceof FeedFragment)
+            manager.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
         FragmentTransaction transaction = manager.beginTransaction();
         transaction.replace(R.id.framelayout_for_fragment, fragment, fragment.getTag());
-        transaction.commit();
+        transaction.addToBackStack(fragment.getTag()).commit();
     }
 
     public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {

app/src/main/java/in/ac/iitb/gymkhana/iitbapp/fragment/CalendarFragment.java

@@ -11,6 +11,7 @@ import android.view.ViewGroup;
 import android.widget.CalendarView;
 import android.widget.Toast;
 
+import in.ac.iitb.gymkhana.iitbapp.MainActivity;
 import in.ac.iitb.gymkhana.iitbapp.R;
 
 /**
@@ -58,11 +59,7 @@ public class CalendarFragment extends BaseFragment {
             @Override
             public void onClick(View v) {
                 AddEventFragment addEventFragment = new AddEventFragment();
-                addEventFragment.setArguments(getArguments());
-                FragmentTransaction ft = getChildFragmentManager().beginTransaction();
-                ft.replace(R.id.calendar_layout, addEventFragment);
-                ft.addToBackStack("addEvent");
-                ft.commit();
+                ((MainActivity) getActivity()).updateFragment(addEventFragment);
             }
         });
         return view;

app/src/main/java/in/ac/iitb/gymkhana/iitbapp/fragment/FeedFragment.java

@@ -21,6 +21,7 @@ import java.util.List;
 import in.ac.iitb.gymkhana.iitbapp.ActivityBuffer;
 import in.ac.iitb.gymkhana.iitbapp.Constants;
 import in.ac.iitb.gymkhana.iitbapp.ItemClickListener;
+import in.ac.iitb.gymkhana.iitbapp.MainActivity;
 import in.ac.iitb.gymkhana.iitbapp.R;
 import in.ac.iitb.gymkhana.iitbapp.adapter.FeedAdapter;
 import in.ac.iitb.gymkhana.iitbapp.api.RetrofitInterface;