Я получаю эту ошибку, когда нажимаю на второй фрагмент в ящике навигации в приложении. Второй фрагмент, где я пытаюсь подключиться к базе данных Firebase. Я не понимаю почему, потому что я использовал плагин Google в build.gradle, использовал последний путь к классу и попытался поместить все необходимые зависимости в build.gradle. У кого-нибудь есть подсказка и помогите мне с этим?
2019-11-07 18:39:44.356 21884-21884/com.example.appv1 E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.appv1, PID: 21884
java.lang.NullPointerException: Firebase Database component is not present.
at com.google.android.gms.common.internal.Preconditions.checkNotNull(Unknown Source)
at com.google.firebase.database.FirebaseDatabase.getInstance(com.google.firebase:firebase-database@@19.2.0:114)
at com.google.firebase.database.FirebaseDatabase.getInstance(com.google.firebase:firebase-database@@19.2.0:57)
at com.example.appv1.SecondFragment.onCreateView(SecondFragment.java:62)
build.gradle (app)
apply plugin: 'com.android.application'
repositories {
mavenLocal()
flatDir {
dirs 'libs'
}
}
android {
compileSdkVersion 28
buildToolsVersion "28.0.3"
defaultConfig {
applicationId "com.example.appv1"
minSdkVersion 16
targetSdkVersion 28
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
testImplementation 'junit:junit:4.12'
implementation 'androidx.appcompat:appcompat:1.0.0'
implementation 'com.google.android.material:material:1.0.0'
implementation 'androidx.coordinatorlayout:coordinatorlayout:1.0.0-alpha1'
implementation "androidx.constraintlayout:constraintlayout:1.1.3"
implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
androidTestImplementation 'androidx.test:runner:1.1.0'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.0'
// Displaying images
implementation 'com.github.bumptech.glide:glide:3.6.1'
// Firebase
//implementation 'com.google.firebase:firebase-database:9.6.0'
//implementation 'com.google.firebase:firebase-auth:9.6.0'
implementation 'com.google.firebase:firebase-database:19.2.0'
implementation 'com.google.firebase:firebase-auth:19.1.0'
implementation 'com.google.firebase:firebase-analytics:17.2.1'
implementation 'com.google.firebase:firebase-firestore:21.2.1'
// FirebaseUI
implementation 'com.firebaseui:firebase-ui-auth:4.3.1'
}
apply plugin: 'com.google.gms.google-services'
}
buil.graddle
buildscript {
repositories {
google()
jcenter()
}
dependencies {
classpath 'com.android.tools.build:gradle:3.4.2'
classpath 'com.google.gms:google-services:4.3.2'
// NOTE: Do not place your application dependencies here; they belong
// in the individual module build.gradle files
}
}
allprojects {
repositories {
google()
jcenter()
}
}
task clean(type: Delete) {
delete rootProject.buildDir
}
У меня есть этовнутри фрагмента, который вызывает ошибку:
mFirebaseDatabase = FirebaseDatabase.getInstance();
mMessagesDatabaseReference = mFirebaseDatabase.getReference().child("messages");
Я также пытался использовать FirebaseApp.initializeApp(this); как во фрагменте, так и в MainActivity, но получаю ту же ошибку.
Редактировать:
MainActivity.java
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
FirebaseApp.initializeApp(getApplicationContext());
setContentView(R.layout.activity_main);
/**
* Navigation drawer
*/
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerLayout drawer = findViewById(R.id.drawer_layout);
NavigationView navigationView = findViewById(R.id.nav_view);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.addDrawerListener(toggle);
toggle.syncState();
navigationView.setNavigationItemSelectedListener(this);
}
@Override
public void onBackPressed() {
DrawerLayout drawer = findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.sign_out_menu) {
return true;
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
FragmentManager fragmentManager=getSupportFragmentManager();
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_sign_in){
fragmentManager.beginTransaction().replace(R.id.content_frame, new LogInFragment()).commit();
}
if (id == R.id.nav_add) {
fragmentManager.beginTransaction().replace(R.id.content_frame, new FirstFragment()).commit();
// Handle the camera action
} else if (id == R.id.nav_second_layout) {
fragmentManager.beginTransaction().replace(R.id.content_frame, new SecondFragment()).commit();
} else if (id == R.id.nav_third_layout) {
fragmentManager.beginTransaction().replace(R.id.content_frame, new ThirdFragment()).commit();
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
DrawerLayout drawer = findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
SecondFragment.java
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
setHasOptionsMenu(true);
myView=inflater.inflate(R.layout.nav_second_layout, container, false);
mUsername = ANONYMOUS;
// Initialize Firebase components
mFirebaseDatabase = FirebaseDatabase.getInstance();
mMessagesDatabaseReference = mFirebaseDatabase.getReference().child("messages");
// Initialize references to views
mProgressBar = (ProgressBar) myView.findViewById(R.id.progressBar);
mMessageListView = (ListView)myView.findViewById(R.id.messageListView);
mPhotoPickerButton = (ImageButton) myView.findViewById(R.id.photoPickerButton);
mMessageEditText = (EditText) myView.findViewById(R.id.messageEditText);
mSendButton = (Button) myView.findViewById(R.id.sendButton);
// Initialize message ListView and its adapter
List<FriendlyMessage> friendlyMessages = new ArrayList<>();
mMessageAdapter = new MessageAdapter(SecondFragment.this.getActivity(), R.layout.item_message, friendlyMessages);
mMessageListView.setAdapter(mMessageAdapter);
// Initialize progress bar
mProgressBar.setVisibility(ProgressBar.INVISIBLE);
// ImagePickerButton shows an image picker to upload a image for a message
mPhotoPickerButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// TODO: Fire an intent to show an image picker
}
});
// Enable Send button when there's text to send
mMessageEditText.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
if (charSequence.toString().trim().length() > 0) {
mSendButton.setEnabled(true);
} else {
mSendButton.setEnabled(false);
}
}
@Override
public void afterTextChanged(Editable editable) {
}
});
mMessageEditText.setFilters(new InputFilter[]{new InputFilter.LengthFilter(DEFAULT_MSG_LENGTH_LIMIT)});
// Send button sends a message and clears the EditText
mSendButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// Send messages on click
FriendlyMessage friendlyMessage = new FriendlyMessage(mMessageEditText.getText().toString(), mUsername, null);
mMessagesDatabaseReference.push().setValue(friendlyMessage);
// Clear input box
mMessageEditText.setText("");
}
});
return myView;
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
inflater.inflate(R.menu.main, menu) ;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
return super.onOptionsItemSelected(item);
}
}