Attempt to invoke virtual method on a null object reference - Firebase database android -


i trying read 'resname' , 'status' values pjsxhqxcyxdsv07lxvzu7buvhkf2 under business_info node firebase database, seen here.

i keep getting error:

attempt invoke virtual method 'java.lang.string com.example.android.project_water.utilities.restaurantinformation.getresname()' on null object reference.

does know how solve this? please let me know if more info needed.

code:

    public class info extends fragment {          private databasereference mdatabase;         private firebaseauth firebaseauth;         private string businessid;         private textview resnamechange, statuschange;          public info() {         }          @override         public view oncreateview(layoutinflater inflater, viewgroup container,                                  bundle savedinstancestate) {              view rootview = inflater.inflate(r.layout.fragment_info, container, false);              sharedpreferences businessid1 = getactivity().getsharedpreferences("business_id", context.mode_private);             businessid = businessid1.getstring("businessid", "businessidnotfound");             log.i("business key is: ", businessid);              firebaseauth = firebaseauth.getinstance();             mdatabase = firebasedatabase.getinstance().getreference();              resnamechange = rootview.findviewbyid(r.id.resnamechange);             statuschange = rootview.findviewbyid(r.id.statuschange);              mdatabase.addvalueeventlistener(new valueeventlistener() {                 @override                 public void ondatachange(datasnapshot datasnapshot) {                     showdata(datasnapshot);                 }                  @override                 public void oncancelled(databaseerror databaseerror) {                  }             });              return rootview;         }          public void showdata(datasnapshot datasnapshot) {              if (datasnapshot.child("business_info").child(businessid).exists()) {                 (datasnapshot ds : datasnapshot.getchildren()) {                     restaurantinformation resinfo = new restaurantinformation(); //error on line below******                     resinfo.setresname(ds.child(businessid).getvalue(restaurantinformation.class).getresname());                     resinfo.setstatus(ds.child(businessid).getvalue(restaurantinformation.class).getstatus());                      resnamechange.settext(resinfo.getresname());                     statuschange.settext(resinfo.getstatus());                 }             } else {                 resnamechange.settext("name");                 statuschange.settext("online");             }          }      }

my model

public class restaurantinformation {      private string resname;     private string status;      public restaurantinformation() {      }      public restaurantinformation(string resname) {         this.resname = resname;     }      public restaurantinformation(string resname, string status) {         this.resname = resname;         this.status = status;     }      public string getresname() {         return resname;     }      public void setresname(string resname) {         this.resname = resname;     }      public string getstatus() {         return status;     }      public void setstatus(string status) {         this.status = status;     } }

your current code downloading entire database , tries figure out show client-side. wasteful use of user's bandwidth. recommend listening business you're interested in:

mdatabase = firebasedatabase.getinstance().getreference(); mdatabase.child("business_info").child(businessid).addvalueeventlistener(new valueeventlistener() {

then can simplify showdata method to:

public void showdata(datasnapshot snapshot) {      if (snapshot.exists()) {         restaurantinformation resinfo = snapshot.getvalue(restaurantinformation.class)          resnamechange.settext(resinfo.getresname());         statuschange.settext(resinfo.getstatus());     } else {         resnamechange.settext("name");         statuschange.settext("online");     }  }

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