This is the error I am facing Caused by: 'java.lang.NullPointerException' Attempt to invoke virtual method 'java.lang.String() on a null object reference at com.example.stdio9.MainActivity.getProfileImage(MainActivity.java:230) at com.example.stdio9.MainActivity.onCreate(MainActivity.java:84)
This is my java code
package com.example.stdio9;
import static com.google.android.gms.auth.api.signin.GoogleSignIn.getClient;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentTransaction;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.example.stdio9.fragment.ExploreFragment;
import com.example.stdio9.fragment.HomeFragment;
import com.example.stdio9.fragment.LibraryFragment;
import com.example.stdio9.fragment.SubscriptionsFragment;
import com.google.android.gms.auth.api.signin.GoogleSignIn;
import com.google.android.gms.auth.api.signin.GoogleSignInAccount;
import com.google.android.gms.auth.api.signin.GoogleSignInClient;
import com.google.android.gms.auth.api.signin.GoogleSignInOptions;
import com.google.android.gms.common.api.ApiException;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.android.material.bottomnavigation.BottomNavigationView;
import com.google.firebase.auth.AuthCredential;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.auth.GoogleAuthProvider;
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 com.squareup.picasso.Picasso;
import java.util.HashMap;
import java.util.Objects;
public class MainActivity extends AppCompatActivity {
Toolbar toolbar;
BottomNavigationView bottomNavigationView;
FrameLayout frameLayout;
private Fragment selectorFragment;
ImageView user_profile_image;
GoogleSignInClient mGoogleSignInClient;
private static final int RC_SIGN_IN = 100;
FirebaseAuth auth;
FirebaseUser user;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle("");
bottomNavigationView = findViewById(R.id.bottom_navigation);
frameLayout = findViewById(R.id.frame_layout);
auth = FirebaseAuth.getInstance();
user = auth.getCurrentUser();
user_profile_image = findViewById(R.id.user_profile_image);
getProfileImage();
GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN).requestIdToken(getString(R.string.default_web_client_id)).requestEmail().build();
mGoogleSignInClient = GoogleSignIn.getClient(MainActivity.this,gso);
bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.home:
selectorFragment = new HomeFragment();
break;
case R.id.explore:
selectorFragment = new ExploreFragment();
break;
case R.id.publish:
Toast.makeText(MainActivity.this, "Upload a video", Toast.LENGTH_SHORT).show();
break;
case R.id.subscriptions:
selectorFragment = new SubscriptionsFragment();
break;
case R.id.library:
selectorFragment = new LibraryFragment();
break;
}
if (selectorFragment != null) {
getSupportFragmentManager().beginTransaction().replace(R.id.frame_layout, selectorFragment).commit();
}
return true;
}
});
getSupportFragmentManager().beginTransaction().replace(R.id.frame_layout, new HomeFragment()).commit();
user_profile_image.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if(user !=null){
Toast.makeText(MainActivity.this, "User Already Signed In", Toast.LENGTH_SHORT).show();
}else{
showDialog();
}
}
});
}
private void showDialog() {
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
builder.setCancelable(true);
ViewGroup viewGroup = findViewById(android.R.id.content);
View view = LayoutInflater.from(getApplicationContext()).inflate(R.layout.item_signin_dialogue,viewGroup,false);
builder.setView(view);
TextView txt_google_signIn = view.findViewById(R.id.txt_google_signIn);
txt_google_signIn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
signIn();
}
});
builder.create().show();
}
private void signIn() {
Intent intent = mGoogleSignInClient.getSignInIntent();
startActivityForResult(intent,RC_SIGN_IN);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if(requestCode == RC_SIGN_IN){
Task<GoogleSignInAccount> task = GoogleSignIn.getSignedInAccountFromIntent(data);
try{
GoogleSignInAccount account = task.getResult(ApiException.class);
AuthCredential credential = GoogleAuthProvider.getCredential(account.getIdToken(),null);
auth.signInWithCredential(credential).addOnCompleteListener(new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
if(task.isSuccessful()){
FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
HashMap<String,Object> map = new HashMap<>();
map.put("username",account.getDisplayName());
map.put("email",account.getEmail());
map.put("profile",String.valueOf(account.getPhotoUrl()));
map.put("uid", firebaseUser.getUid());
map.put("search",account.getDisplayName().toLowerCase());
DatabaseReference reference = FirebaseDatabase.getInstance().getReference().child("Users");
reference.child(firebaseUser.getUid()).setValue(map);
}
else{
Toast.makeText(MainActivity.this, task.getException().getMessage(), Toast.LENGTH_SHORT).show();
}
}
});
}
catch(Exception e){
Toast.makeText(this, e.getMessage(), Toast.LENGTH_SHORT).show();
}
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.toolbar_menu, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(@NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.notification:
Toast.makeText(this, "Notification", Toast.LENGTH_SHORT).show();
break;
case R.id.search:
Toast.makeText(this, "Search", Toast.LENGTH_SHORT).show();
break;
default:
return super.onOptionsItemSelected(item);
}
return false;
}
private void getProfileImage(){
DatabaseReference reference = FirebaseDatabase.getInstance().getReference().child("Users");
reference.child(user.getUid()).addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot snapshot) {
if(snapshot.exists()){
String p =snapshot.child("profile").getValue().toString();
Picasso.get().load(p).placeholder(R.drawable.ic_baseline_account_circle).into(user_profile_image);
}
}
@Override
public void onCancelled(@NonNull DatabaseError error) {
Toast.makeText(MainActivity.this,error.getMessage(),Toast.LENGTH_SHORT).show();
}
});
}
}
My XML code:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<com.google.android.material.appbar.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@ id/appBar">
<androidx.appcompat.widget.Toolbar
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@ id/toolbar"
android:background="@color/white"
app:menu="@menu/toolbar_menu">
<ImageView
android:layout_width="70dp"
android:layout_height="50dp"
android:src="@drawable/icon1"
android:adjustViewBounds="true"
android:id="@ id/icon"/>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<de.hdodenhof.circleimageview.CircleImageView
android:layout_width="24dp"
android:layout_height="24dp"
android:src="@drawable/ic_baseline_account_circle"
android:layout_marginStart="190dp"
android:id="@ id/user_profile_image"/>
</RelativeLayout>
</androidx.appcompat.widget.Toolbar>
</com.google.android.material.appbar.AppBarLayout>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@ id/appBar"
android:layout_above="@ id/bottom_navigation"
android:id="@ id/frame_layout"/>
<com.google.android.material.bottomnavigation.BottomNavigationView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/white"
app:menu="@menu/bottom_menu"
android:layout_alignParentBottom="true"
app:itemTextColor="@color/black"
app:itemIconTint="@color/black"
app:itemRippleColor="@color/cardview_dark_background"
android:id="@ id/bottom_navigation"
app:labelVisibilityMode="labeled"/>
</RelativeLayout>
Error in this particular lines
reference.child(user.getUid()).addValueEventListener(new ValueEventListener() {
and `getProfileImage();
I am new to android can someone please help...will really appretiate
CodePudding user response：
If it's referring to the line:
reference.child(user.getUid()).addValueEventListener(new ValueEventListener()
then it's telling you that either "reference" or "user" is null, and you're note checking for it. So, you need to do something like:
if(reference == null || user == null) return;
right before that line, or alternatively, put in some logic to handle the case of either of those being NULL