Wsrtjtyk

Please help here (fore job interview)

I'm trying to upload an image , when it's starts uploding , it crashes
and removes the two basic childrens (image,thumb image)

E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.pc.newchatj, PID: 9350
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.Object.toString()' on a null object reference
at com.example.pc.newchatj.SettingsActivity$1.onDataChange(SettingsActivity.java:103)
at com.google.firebase.database.core.ValueEventRegistration.fireEvent(com.google.firebase:firebase-database@@16.0.4:75)
at com.google.firebase.database.core.view.DataEvent.fire(com.google.firebase:firebase-database@@16.0.4:63)
at com.google.firebase.database.core.view.EventRaiser$1.run(com.google.firebase:firebase-database@@16.0.4:55)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

And in my Firebase database it removes the two childrens (image , thumb_image)

anyone please help

mUserDatabase.addValueEventListener(new ValueEventListener() {

        @Override

        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {



            String name = dataSnapshot.child("name").getValue().toString();

            String image = dataSnapshot.child("image").getValue().toString();

            String status = dataSnapshot.child("status").getValue().toString();

            String thumb_image = dataSnapshot.child("thumb_image").getValue().toString();



            mName.setText(name);

            mStatus.setText(status);



            if (!image.equals("default")) {

                Picasso.get().load(image).placeholder(R.drawable.default_avatar).into(mDisplayImage);

            }

        }



        @Override

        public void onCancelled(@NonNull DatabaseError databaseError) {



        }

    });

I've added StorageReference for both (image , thumb image)

filepath.putFile(resultUri).addOnCompleteListener(new OnCompleteListener<UploadTask.TaskSnapshot>() {

                @Override

                public void onComplete(@NonNull Task<UploadTask.TaskSnapshot> task) {

                if (task.isSuccessful()){



                    UploadTask uploadTask = thumb_filepath.putBytes(thumb_byte);

                    uploadTask.addOnCompleteListener(new OnCompleteListener<UploadTask.TaskSnapshot>() {

                        @Override

                        public void onComplete(@NonNull Task<UploadTask.TaskSnapshot> thumb_task) {



                            if (thumb_task.isSuccessful()){



                                //getting regular image download url

                                filepath.getDownloadUrl().addOnSuccessListener(new OnSuccessListener<Uri>() {

                                    @Override

                                    public void onSuccess(Uri uri) {



                                        download_urll = uri.toString();



                                    }

                                }).addOnFailureListener(new OnFailureListener() {

                                    @Override

                                    public void onFailure(@NonNull Exception e) {

                                        Toast.makeText(SettingsActivity.this, "Regular fail", Toast.LENGTH_SHORT).show();

                                    }

                                });





                                //getting thumbnail download url

                                thumb_filepath.getDownloadUrl().addOnSuccessListener(new OnSuccessListener<Uri>() {

                                    @Override

                                    public void onSuccess(Uri thumb_uri) {



                                        thumb_downloadUrl = thumb_uri.toString();



                                    }

                                }).addOnFailureListener(new OnFailureListener() {

                                    @Override

                                    public void onFailure(@NonNull Exception e) {

                                        Toast.makeText(SettingsActivity.this, "thumb failed", Toast.LENGTH_SHORT).show();

                                    }

                                });





                                Map update_hashMap = new HashMap();

                                update_hashMap.put("image" , download_urll);

                                update_hashMap.put("thumb_image" , thumb_downloadUrl);





                                mUserDatabase.updateChildren(update_hashMap).addOnCompleteListener(new OnCompleteListener<Void>() {

                                    @Override

                                    public void onComplete(@NonNull Task<Void> task) {



                                        if (task.isSuccessful()){

                                            avi_settings.smoothToHide();

                                            avi_settings.setVisibility(View.INVISIBLE);

                                            Toast.makeText(SettingsActivity.this, "Successfully uploaded", Toast.LENGTH_SHORT).show();





                                        }



                                    }

                                });



                            }







                        }

                    });



                    Toast.makeText(SettingsActivity.this, "working", Toast.LENGTH_SHORT).show();

                }else {

                    Toast.makeText(SettingsActivity.this, "Error uploading file", Toast.LENGTH_SHORT).show();

                    avi_settings.smoothToHide();

                    avi_settings.setVisibility(View.INVISIBLE);

                }

                }

            });

Before trying to get the data from the dataSnapshot object, you should check if that data actually exist:

mUserDatabase.addValueEventListener(new ValueEventListener() {

    @Override

    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

        if (dataSnapshot.exists()) { //Check for existens

            String name = dataSnapshot.child("name").getValue(String.class);

            String image = dataSnapshot.child("image").getValue(String.class);

            String status = dataSnapshot.child("status").getValue(String.class);

            String thumb_image = dataSnapshot.child("thumb_image").getValue(String.class);



            mName.setText(name);

            mStatus.setText(status);



            if (!image.equals("default")) {

                Picasso.get().load(image).placeholder(R.drawable.default_avatar).into(mDisplayImage);

            }   

        }

    }



    @Override

    public void onCancelled(@NonNull DatabaseError databaseError) {

        Log.d(TAG, databaseError.getMessage()); //Don't ignore errors!

    }

});

Also is best to pass String.class to the getValue() method insted of casting it to String. You will not get any NullPointerException anymore.

As you wrote NullPointerException rises in line

String name = dataSnapshot.child("name").getValue().toString();

The error message says you try to invoke .toString() on an null object.
You should save the result from String name = dataSnapshot.child("name").getValue() and check if it's not null before calling .toSring() method.