java.lang.NullPointerException выбрасывает из приложения

Question

Что измените чтоб не выбрасывало из эмулятора после выхода из окна диалога? Выдает ошибку :

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.blum, PID: 8594
    java.lang.NullPointerException: You cannot start a load on a not yet attached View or a Fragment where getActivity() returns null (which usually occurs when getActivity() is called before the Fragment is attached or after the Fragment is destroyed).
        at com.bumptech.glide.util.Preconditions.checkNotNull(Preconditions.java:29)
        at com.bumptech.glide.Glide.getRetriever(Glide.java:744)
        at com.bumptech.glide.Glide.with(Glide.java:776)
        at com.example.blum.Fragments.ProfileFragment$1.onDataChange(ProfileFragment.java:80)
        at com.google.firebase.database.core.ValueEventRegistration.fireEvent(ValueEventRegistration.java:75)
        at com.google.firebase.database.core.view.DataEvent.fire(DataEvent.java:63)
        at com.google.firebase.database.core.view.EventRaiser$1.run(EventRaiser.java:55)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

MessageActivity:

import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.TextView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import com.bumptech.glide.Glide;
import com.example.blum.Adapter.MessageAdapter;
import com.example.blum.Model.Chat;
import com.example.blum.Model.User;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import de.hdodenhof.circleimageview.CircleImageView;

public class MessageActivity extends AppCompatActivity {

    CircleImageView profile_image;
    TextView username;

    FirebaseUser fuser;
    DatabaseReference reference;

    ImageButton btn_send;
    EditText text_send;

    MessageAdapter messageAdapter;
    List<Chat> mchat;

    RecyclerView recyclerView;

    Intent intent;

    ValueEventListener seenListener;

    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_message);

        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setTitle("");
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        toolbar.setNavigationOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // и это тоже
                startActivity(new Intent(MessageActivity.this, MainActivity.class).setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP));
             }
        });

        recyclerView = findViewById(R.id.recycler_view);
        recyclerView.setHasFixedSize(true);
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getApplicationContext());
        linearLayoutManager.setStackFromEnd(true);
        recyclerView.setLayoutManager(linearLayoutManager);

        profile_image = findViewById(R.id.profile_image);
        username = findViewById(R.id.username);
        btn_send = findViewById(R.id.btn_send);
        text_send = findViewById(R.id.text_send);


        intent = getIntent();
        String userid = intent.getStringExtra("userid");

        btn_send.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String msg = text_send.getText().toString();
                if (!msg.equals("")) {
                    sendMessage(fuser.getUid(),userid, msg);
                } else {
                    Toast.makeText(MessageActivity.this, "Вы не можете отправить пустое сообщение :(", Toast.LENGTH_SHORT).show();
                }
                text_send.setText("");
            }
        });

        fuser = FirebaseAuth.getInstance().getCurrentUser();
        reference = FirebaseDatabase.getInstance().getReference("Users").child(userid);

        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                User user = dataSnapshot.getValue(User.class);
                username.setText(user.getUsername());
                if ("default".equals(user.getImageURL())) {
                    profile_image.setImageResource(R.mipmap.ic_launcher);
                } else {
                    Glide.with(getApplicationContext()).load(user.getImageURL()).into(profile_image);
                }

                readMessages(fuser.getUid(), userid, user.getImageURL());
            }

            @Override
            public void onCancelled(@NonNull DatabaseError error) {

            }
        });

        seenMessage(userid);
    }

    private void seenMessage(String userid) {
        reference = FirebaseDatabase.getInstance().getReference("Chats");
        seenListener = reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                    Chat chat = snapshot.getValue(Chat.class);
                    if (chat.getReceiver().equals(fuser.getUid()) && chat.getSender().equals(userid)) {
                        HashMap<String, Object> hashMap = new HashMap<>();
                        hashMap.put("isseen", true);
                        snapshot.getRef().updateChildren(hashMap);
                    }
                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError error) {

            }
        });
    }

    private void sendMessage(String sender, String receiver, String message){

        DatabaseReference reference = FirebaseDatabase.getInstance().getReference();

        HashMap<String, Object> hashMap = new HashMap<>();
        hashMap.put("sender", sender);
        hashMap.put("receiver", receiver);
        hashMap.put("message", message);
        hashMap.put("isseen", false);


        reference.child("Chats").push().setValue(hashMap);


    }

    private void readMessages(final String myid, final String userid, String imageurl) {
        mchat = new ArrayList<>();

        reference = FirebaseDatabase.getInstance().getReference("Chats");
        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                mchat.clear();
                for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                    Chat chat = snapshot.getValue(Chat.class);
                    if (chat.getReceiver().equals(myid) && chat.getSender().equals(userid) ||
                    chat.getReceiver().equals(userid) && chat.getSender().equals(myid)) {
                        mchat.add(chat);
                    }

                    messageAdapter = new MessageAdapter(MessageActivity.this, mchat, imageurl);
                    recyclerView.setAdapter(messageAdapter);
                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });
    }

    private void status(String status) {
        reference = FirebaseDatabase.getInstance().getReference("Users").child(fuser.getUid());

        HashMap<String, Object> hashMap = new HashMap<>();
        hashMap.put("status", status);

        reference.updateChildren(hashMap);
    }

    @Override
    protected void onResume() {
        super.onResume();
        status("В сети :)");
    }

    @Override
    protected void onPause() {
        super.onPause();
        reference.removeEventListener(seenListener);
        status("Не в сети :(");
    }
}

ProfileFragment:

public class ProfileFragment extends Fragment {

    CircleImageView image_profile;
    TextView username;

    DatabaseReference reference;
    FirebaseUser fuser;

    StorageReference storageReference;
    private static final int IMAGE_REQUEST = 1;
    private Uri imageUri;
    private StorageTask uploadTask;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_profile, container, false);

        image_profile = view.findViewById(R.id.profile_image);
        username = view.findViewById(R.id.username);

        storageReference = FirebaseStorage.getInstance().getReference("uploads");

        fuser = FirebaseAuth.getInstance().getCurrentUser();
        reference = FirebaseDatabase.getInstance().getReference("Users").child(fuser.getUid());

        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                User user = dataSnapshot.getValue(User.class);
                username.setText(user.getUsername());
                if (user.getImageURL() != null && user.getImageURL().equals("default"));
                      else {
                        Glide.with(getContext()).load(user.getImageURL()).into(image_profile);
                    }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });

        image_profile.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                openImage();
            }
        });

        return view;
    }

    private void openImage() {
        Intent intent = new Intent();
        intent.setType("image/*");
        intent.setAction(Intent.ACTION_GET_CONTENT);
        startActivityForResult(intent, IMAGE_REQUEST);
    }

    private String getFileExtension(Uri uri) {
        ContentResolver contentResolver = getContext().getContentResolver();
        MimeTypeMap mimeTypeMap = MimeTypeMap.getSingleton();
        return mimeTypeMap.getExtensionFromMimeType(contentResolver.getType(uri));
    }

    private void uploadImage() {
        final ProgressDialog pd = new ProgressDialog(getContext());
        pd.setMessage("Uploading");
        pd.show();

        if (imageUri != null) {
            final StorageReference fileReference = storageReference.child(System.currentTimeMillis()
                    +"."+getFileExtension(imageUri));

            uploadTask = fileReference.putFile(imageUri);
            uploadTask.continueWithTask(new Continuation<UploadTask.TaskSnapshot, Task<Uri>>() {
                @Override
                public Task<Uri> then(@NonNull Task<UploadTask.TaskSnapshot> task) throws Exception {
                    if (!task.isSuccessful()) {
                        throw task.getException();
                    }

                    return fileReference.getDownloadUrl();
                }
            }).addOnCompleteListener(new OnCompleteListener<Uri>() {
                @Override
                public void onComplete(@NonNull Task<Uri> task) {
                    if (task.isSuccessful()) {
                        Uri downloadUri = task.getResult();
                        String mUri = downloadUri.toString();

                        reference = FirebaseDatabase.getInstance().getReference("Users").child(fuser.getUid());
                        HashMap<String, Object> map = new HashMap<>();
                        map.put("imageURL", mUri);
                        reference.updateChildren(map);

                        pd.dismiss();
                    } else {
                        Toast.makeText(getContext(), "Ошибка!", Toast.LENGTH_SHORT).show();
                        pd.dismiss();
                    }
                }
            }).addOnFailureListener(new OnFailureListener() {
                @Override
                public void onFailure(@NonNull Exception e) {
                    Toast.makeText(getContext(), e.getMessage(), Toast.LENGTH_SHORT).show();
                    pd.dismiss();
                }
            });
        } else {
            Toast.makeText(getContext(), "Изображение не выбрано!", Toast.LENGTH_SHORT).show();
        }
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == IMAGE_REQUEST && resultCode == RESULT_OK
                && data != null && data.getData() != null) {
            imageUri = data.getData();

            if (uploadTask != null && uploadTask.isInProgress()) {
                Toast.makeText(getContext(), "Загружаю", Toast.LENGTH_SHORT).show();
            } else {
                uploadImage();
            }
        }
    }

MainActivity:

public class MainActivity extends AppCompatActivity {

    CircleImageView profile_image;
    TextView username;

    FirebaseUser firebaseUser;
    DatabaseReference reference;



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

        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setTitle("");

        profile_image = findViewById(R.id.profile_image);
        username = findViewById(R.id.username);

        firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
        reference = FirebaseDatabase.getInstance().getReference("Users").child(firebaseUser.getUid());

        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                User user = dataSnapshot.getValue(User.class);
                username.setText(user.getUsername());
                if (user.getImageURL().equals("default")){
                    profile_image.setImageResource(R.mipmap.ic_launcher);
                } else {

                    Glide.with(getApplicationContext()).load(user.getImageURL()).into(profile_image);
                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError error) {

            }
        });

        TabLayout tabLayout = findViewById(R.id.tab_layout);
        ViewPager viewPager = findViewById(R.id.view_pager);

        ViewPagerAdapter viewPagerAdapter = new ViewPagerAdapter(getSupportFragmentManager());

        viewPagerAdapter.addFragment(new ChatsFragment(), "Чат");
        viewPagerAdapter.addFragment(new UsersFragment(), "Контакты");
        viewPagerAdapter.addFragment(new ProfileFragment(), "Профиль");

        viewPager.setAdapter(viewPagerAdapter);

        tabLayout.setupWithViewPager(viewPager);


    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
       switch (item.getItemId()){

           case R.id.logout:
            FirebaseAuth.getInstance().signOut();
            // измените этот код, потому что ваше приложение выйдет из строя
            startActivity(new Intent(MainActivity.this, StartActivity.class).setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP));
            return true;
        }

        return false;
    }

    class ViewPagerAdapter extends FragmentPagerAdapter {

        private ArrayList<Fragment> fragments;
        private ArrayList<String> titles;

        ViewPagerAdapter(FragmentManager fm){
            super(fm);
            this.fragments = new ArrayList<>();
            this.titles = new ArrayList<>();
        }

        @NonNull
        @Override
        public Fragment getItem(int position) {
            return fragments.get(position);
        }

        @Override
        public int getCount() {
            return fragments.size();
        }

        public void addFragment(Fragment fragment, String title){
            fragments.add(fragment);
            titles.add(title);
        }

        //Ctrl + O

        @Nullable
        @Override
        public CharSequence getPageTitle(int position) { return titles.get(position); }
    }

    private void status(String status) {
        reference = FirebaseDatabase.getInstance().getReference("Users").child(firebaseUser.getUid());

        HashMap<String, Object> hashMap = new HashMap<>();
        hashMap.put("status", status);

        reference.updateChildren(hashMap);
    }

    @Override
    protected void onResume() {
        super.onResume();
        status("В сети :)");
    }

    @Override
    protected void onPause() {
        super.onPause();
        status("Не в сети :(");
    }
}

Answer 1

java.lang.NullPointerException: You cannot start a load on a not yet attached View or a Fragment where getActivity() returns null (which usually occurs when getActivity() is called before the Fragment is attached or after the Fragment is destroyed).
...
at com.example.blum.Fragments.ProfileFragment$1.onDataChange(ProfileFragment.java:80)

Проблема в том что фрагмент уже не существует, а у вас в onDataChange (своего рода callback) используется getContext() этого уже не существующего фрагмента. Для проверки есть такие функции как isAdded() isDetached() isRemoving()

Исправьте код в ProfileFragment

@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
    User user = dataSnapshot.getValue(User.class);
    username.setText(user.getUsername());
    if (user.getImageURL() != null && user.getImageURL().equals("default"));
          else {
            Glide.with(getContext()).load(user.getImageURL()).into(image_profile);
        }
}

На

@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
    User user = dataSnapshot.getValue(User.class);
    username.setText(user.getUsername());
    if (user.getImageURL() != null && user.getImageURL().equals("default"));
          else if (isAdded() && getContext() != null) {
            Glide.with(getContext()).load(user.getImageURL()).into(image_profile);
        }
}

БЛОГ НА HUSL

java.lang.NullPointerException выбрасывает из приложения

Ответы (1 шт):