Android RecyclerView列表视图没有'；t在加载活动时填充，但在按下后退按钮时填充（有时在多次后退时）
我正在使用firebase作为我的数据库。我的recyclerview不会在活动首次加载时填充，但它会在backpress操作后填充，有时会多次backpress HomeActivity.javaAndroid RecyclerView列表视图没有'；t在加载活动时填充，但在按下后退按钮时填充（有时在多次后退时）,android,firebase,android-recyclerview,firebase-realtime-database,firebaseui,Android,Firebase,Android Recyclerview,Firebase Realtime Database,Firebaseui,我正在使用firebase作为我的数据库。我的recyclerview不会在活动首次加载时填充，但它会在backpress操作后填充，有时会多次backpress HomeActivity.java public class HomeActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener { //Recycler Contact list variable
public class HomeActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
//Recycler Contact list variables
private RecyclerView mContactList;
//Firebase Variables
private DatabaseReference rDatabase;
private FirebaseAuth mAuth;
private StorageReference mStorageRef;
private FirebaseAuth.AuthStateListener mAuthListener;
FirebaseUser user;
FirebaseRecyclerAdapter<ContactList,ContactListViewHolder> firebaseRecyclerAdapter;
//Request Contact Constant
private static final int REQUEST_READ_CONTACTS = 0;
private Long contactId;
private Uri downloadUrl = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
if (Build.VERSION.SDK_INT >= 23) {
//do your check here
mayRequestContacts();
}
//initialize Recycler view
mContactList = (RecyclerView) findViewById(R.id.contact_list);
mContactList.setHasFixedSize(true);
mContactList.setLayoutManager(new LinearLayoutManager(this));
//initialize UI elements
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
View headView = navigationView.getHeaderView(0);
TextView uName = (TextView)headView.findViewById(R.id.userName);
ImageView dPhoto = (ImageView)headView.findViewById(R.id.imageView);
TextView mEmail = (TextView)headView.findViewById(R.id.uEmail);
//initialize Firebase variables
mStorageRef = FirebaseStorage.getInstance().getReference();
user = FirebaseAuth.getInstance().getCurrentUser();
rDatabase = FirebaseDatabase.getInstance().getReference().child("users").child(user.getUid()).child(user.getDisplayName()).child("contacts");
mAuth = FirebaseAuth.getInstance();
mAuthListener = new FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
FirebaseUser user = firebaseAuth.getCurrentUser();
if (user == null) {
// user auth state is changed - user is null
// launch login activity
startActivity(new Intent(HomeActivity.this, LoginActivity.class));
finish();
}
}
};
if (user != null) {
// Name, email address, and profile photo Url
String name = user.getDisplayName();
String email = user.getEmail();
Uri photoUrl = user.getPhotoUrl();
System.out.println(name);
if(name!=null) {
uName.setText(name);
mEmail.setText(email);
}
if(photoUrl!=null){
Picasso.with(this)
.load(photoUrl)
.into(dPhoto);
}
// The user's ID, unique to the Firebase project. Do NOT use this value to
// authenticate with your backend server, if you have one. Use
// FirebaseUser.getToken() instead.
}
//initialize FirebaseRecyclerAdapter
firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<ContactList, ContactListViewHolder>(
ContactList.class,
R.layout.contact_list_row,
ContactListViewHolder.class,
rDatabase
) {
@Override
protected void populateViewHolder(ContactListViewHolder viewHolder, ContactList model, int position) {
viewHolder.setName(model.getName());
viewHolder.setPhone(model.getPhone());
}
};
mContactList.setAdapter(firebaseRecyclerAdapter); //set adapter for recycler view
setSupportActionBar(toolbar); //instantiate toolbar
//initialize floating action button
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with add contact or agenda", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
//initialize navigation drawer
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle mDrawerToggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.addDrawerListener(mDrawerToggle);
mDrawerToggle.syncState();
navigationView.setNavigationItemSelectedListener(this); //listen if any item selected
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) 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.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_importContacts) {
// Handle the Import Contacts Action
final ProgressDialog ringProgressDialog = ProgressDialog.show(HomeActivity.this, "Please Wait", "Importing Contacts", true);
ringProgressDialog.setCancelable(true);
new Thread(new Runnable() {
@Override
public void run() {
try {
//user = FirebaseAuth.getInstance().getCurrentUser(); //Get the currently logged in user information
//Uid = user.getUid(); //Get User ID
//UName = user.getDisplayName();
//Initialize cursor to import contacts
ContentResolver cr = getContentResolver();
Cursor cur = cr.query(ContactsContract.Contacts.CONTENT_URI,
null, null, null, null);
assert cur != null;
if (cur.getCount() > 0) {
while (cur.moveToNext()) {
//Get current Contact ID
contactId=cur.getLong(cur.getColumnIndex(ContactsContract.Contacts._ID));
//Get current Contact Name
String cName = cur.getString(cur.getColumnIndex(
ContactsContract.Contacts.DISPLAY_NAME));
//Get Current Contact URI
Uri contactUri = ContentUris.withAppendedId(ContactsContract.Contacts.CONTENT_URI, contactId);
//Get Current Contact Photo Uri
Uri displayPhotoUri=null;
if(Uri.withAppendedPath(contactUri, ContactsContract.Contacts.Photo.DISPLAY_PHOTO)!=null){
displayPhotoUri = Uri.withAppendedPath(contactUri, ContactsContract.Contacts.Photo.DISPLAY_PHOTO);
}
try {
AssetFileDescriptor fd =
getContentResolver().openAssetFileDescriptor(displayPhotoUri, "r");
} catch (IOException e) {
// return null;
}
if(contactId!=null && cName!=null && displayPhotoUri!=null){
boolean flag = true;
Cursor emailCursor = cr.query(ContactsContract.CommonDataKinds.Email.CONTENT_URI,
null,
ContactsContract.CommonDataKinds.Email.CONTACT_ID + " = ?", new String[] {contactId.toString()}, null);
if(cur.getInt(cur.getColumnIndex(
ContactsContract.Contacts.HAS_PHONE_NUMBER)) <=0){
flag = false;
}
else{
//Import Contact Photo
StorageReference filepath = mStorageRef.child("users/"+user.getUid()+"/"+contactId+"/contactPhoto").child(displayPhotoUri.getLastPathSegment());
filepath.putFile(displayPhotoUri).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
@Override
public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
// System.out.println(photoUri.toString()); //debug point
downloadUrl = taskSnapshot.getDownloadUrl();
rDatabase.child(contactId.toString()).child("photoUrl").setValue(downloadUrl.toString());
}
}).addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
}
});
//Import Contact Email ID if Any
assert emailCursor != null;
while (emailCursor.moveToNext())
{
String cEmail = emailCursor.getString(emailCursor.getColumnIndex(ContactsContract.CommonDataKinds.Email.DATA));
int type = emailCursor.getInt(emailCursor.getColumnIndex(ContactsContract.CommonDataKinds.Email.DATA));
rDatabase.child(contactId.toString()).child("email").setValue(cEmail);
}
emailCursor.close();
Cursor pCur = cr.query(
ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
null,
ContactsContract.CommonDataKinds.Phone.CONTACT_ID +" = ?",
new String[]{contactId.toString()}, null);
while (pCur.moveToNext()) {
String phoneNo = pCur.getString(pCur.getColumnIndex(
ContactsContract.CommonDataKinds.Phone.NUMBER));
//Import Contact Phone No.
rDatabase.child(contactId.toString()).child("phone").setValue(phoneNo);
//Import Contact Name
rDatabase.child(contactId.toString()).child("name").setValue(cName);
}
pCur.close();
}}
}
} cur.close();
Thread.sleep(10000);
} catch (Exception e) {
return;
}
ringProgressDialog.dismiss();
}
}).start();
} else if (id == R.id.nav_logout) {
mAuth.signOut(); //Log out user method
} else if (id == R.id.nav_send) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
//Method to request contacts (Required for API 23 and greater)
private boolean mayRequestContacts() {
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
return true;
}
if (checkSelfPermission(READ_CONTACTS) == PackageManager.PERMISSION_GRANTED) {
return true;
}
if (shouldShowRequestPermissionRationale(READ_CONTACTS)) {
if (checkSelfPermission(Manifest.permission.READ_CONTACTS) == PackageManager.PERMISSION_GRANTED) {
Toast.makeText(HomeActivity.this, "Permission Granted",
Toast.LENGTH_LONG).show();
//File write logic here
return true;
}
} else {
requestPermissions(new String[]{READ_CONTACTS}, REQUEST_READ_CONTACTS);
}
return false;
}
public void onStart() {
super.onStart();
mAuth.addAuthStateListener(mAuthListener); //Listen to current user Login status
mContactList.setAdapter(firebaseRecyclerAdapter); //Set adapter for contact list recycler view
}
@Override
public void onStop() {
super.onStop();
if (mAuthListener != null) {
mAuth.removeAuthStateListener(mAuthListener);
}
}
//ViewHolder for ContactList Recycler View
public static class ContactListViewHolder extends RecyclerView.ViewHolder{
View mView;
TextView contact_Name;
TextView contact_Phone;
public ContactListViewHolder(View itemView) {
super(itemView);
mView = itemView;
}
public void setName(String name){
contact_Name = (TextView) itemView.findViewById(R.id.ContactName);
contact_Name.setText(name);
}
public void setPhone(String phone){
contact_Phone = (TextView) itemView.findViewById(R.id.ContactPhone);
contact_Phone.setText(phone);
}
}
<?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:id="@+id/content_main"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="neeti.contactapp.HomeActivity"
tools:showIn="@layout/activity_main">
<android.support.v7.widget.RecyclerView
android:id="@+id/contact_list"
android:scrollbars="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</RelativeLayout>
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:focusable="true"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:paddingTop="10dp"
android:paddingBottom="10dp"
android:clickable="true"
android:background="?android:attr/selectableItemBackground"
android:orientation="vertical">
<TextView
android:id="@+id/ContactName"
android:textColor="@color/ContactName"
android:textSize="16dp"
android:textStyle="bold"
android:layout_alignParentTop="true"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/ContactPhone"
android:layout_below="@id/ContactName"
android:textColor="@color/ContactPhone"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</RelativeLayout>
您缺少
firebaseRecyclerAdapter.notifyDataSetChanged（）
然后将适配器设置为：
mContactList.setAdapter(firebaseRecyclerAdapter);
您缺少firebaseRecyclerAdapter.notifyDataSetChanged（）
然后将适配器设置为：
mContactList.setAdapter(firebaseRecyclerAdapter);
谢谢你的建议！谢谢你的建议！