无论登录哪个用户，arrayList总是装载来自Firebase数据库的用户信息？ [英] arrayList always loaded with user info from Firebase database regardless of which user is signed in ؟

问题描述

在showdata方法中，当我运行应用程序并用任何用户登录时，加载FirebaseUser信息的方法中的arrayList总是加载User_03信息，

调试show即：

• DataSnapshot ds加载了正确的登录用户值（右键和信息）。
  
• uInfo（携带用户信息登录的对象）从数据库中加载正确的数据。 = $ undefined。


• 我认为arryList大小有问题。

我到达断点的时候把它拿到：toastMassege（完成了）。

  public class AddToDatabase extends AppCompatActivity {
 private static final String TAG =AddToDatabase; 
私人ListView userInfolist; 
 private FirebaseAuth mAuth; 
私有FirebaseAuth.AuthStateListener mAuthListener; 
字符串userId; 
 UserInformations uInfo = new UserInformations（）; 
 @Override 
 protected void onCreate（Bundled savedInstanceState）{
 super.onCreate（savedInstanceState）; 
 setContentView（R.layout.activity_add_to_database）; 
 
 userInfolist =（ListView）findViewById（R.id.userInfolist）; 
 mAuth = FirebaseAuth.getInstance（）; 
 FirebaseDatabase mFirebaseDatabase = FirebaseDatabase.getInstance（）; 
 DatabaseReference myRef = mFirebaseDatabase.getReference（）; 
 FirebaseUser user = mAuth.getCurrentUser（）; 
 userId = user.getUid（）; 
 $ b mAuthListener = new FirebaseAuth.AuthStateListener（）{
 @Override $ b $ public void onAuthStateChanged（@NonNull FirebaseAuth firebaseAuth）{
 FirebaseUser user = firebaseAuth.getCurrentUser（）; 
 if（user！= null）{
 Log.d（TAG，onAuthStateChanged：signed_in：+ user.getUid（））; 
 toastMassege（您已成功登录+ 
 user.getEmail（））; 
} else {
 Log.d（TAG，onAuthStateChanged：signed_out）; 
 toastMassege（您已成功登出）; 
} 
} 
}; 
 
 myRef.addValueEventListener（new ValueEventListener（）{
 @Override $ b $ public void onDataChange（DataSnapshot dataSnapshot）{
 showData（dataSnapshot）; 
} 
 @Override 
 public void onCancelled（DatabaseError error）{
} 
}）; （DataSnapshot ds：dataSnapshot.getChildren（））{
 
 private void showData（DataSnapshot dataSnapshot）{
）uInfo.setName（ds.getValue（UserInformations的.class）.getName（））; 
 uInfo.setEmail（ds.getValue（UserInformations.class）.getEmail（））; 
 uInfo.setPhone_num（ds.getValue（UserInformations.class）.getPhone_num（））; 
 
 ArrayList< String> arrayList = new ArrayList<>（）; 
 int listSize = arrayList.size（）; 
 arrayList.add（uInfo.getName（））; 
 arrayList.add（uInfo.getEmail（））; 
 arrayList.add（uInfo.getPhone_num（））; 
 ArrayAdapter< String> adapter = new ArrayAdapter<>（this，android.R.layout.simple_list_item_1，arrayList）; 
 userInfolist.setAdapter（adapter）; 
 toastMassege（完成）; 
 
 $ b @Override 
 public void onStart（）{
 super.onStart（）; 
 mAuth.addAuthStateListener（mAuthListener）; 
 
 @Override 
 public void onStop（）{
 super.onStop（）; 
 if（mAuthListener！= null）{
 mAuth.removeAuthStateListener（mAuthListener）; 
 
 $ b private void toastMassege（String massege）{
 Toast.makeText（this，massege，Toast.LENGTH_SHORT）.show（）; 
 
 
 
 
 
这是类UserInformations 
  class UserInformations {
 
 public String email，name，phone_num; 
 UserInformations（）{
} 
 public String getEmail（）{
 return email; 
} 
 public void setEmail（String email）{
 this.email = email; 
} 
 public String getName（）{
 return name; 
} 
 public void setName（String name）{
 this.name = name; 
} 
 public String getPhone_num（）{
 return phone_num; 
} 
 public void setPhone_num（String phone_num）{
 this.phone_num = phone_num; 
 
 
 $ / code $ / pre 
 $ b 
    
解决方案
这是因为您已经声明了 ArrayList< String> arrayList = new ArrayList<>（）; 在for循环中。这意味着你每次迭代都要创建一个ArrayList类的新实例。
 
 
为了解决这个问题， p> 
 
 
  private void showData（DataSnapshot dataSnapshot）{
 ArrayList< String> arrayList = new ArrayList<>（）; //移动到
 $ b之外（DataSnapshot ds：dataSnapshot.getChildren（））{
 
 uInfo.setName（ds.getValue（UserInformations.class）.getName（））; 
 uInfo.setEmail（ds.getValue（UserInformations.class）.getEmail（））; 
 uInfo.setPhone_num（ds.getValue（UserInformations.class）.getPhone_num（））; 
 
 int listSize = arrayList.size（）; 
 arrayList.add（uInfo.getName（））; 
 arrayList.add（uInfo.getEmail（））; 
 arrayList.add（uInfo.getPhone_num（））; 
 ArrayAdapter< String> adapter = new ArrayAdapter<>（this，android.R.layout.simple_list_item_1，arrayList）; 
 userInfolist.setAdapter（adapter）; 
 toastMassege（完成）; 
} 
} 
  
 
In showdata method witch load FirebaseUser info when I run the app and signed in with any user , arrayList in the method is always loaded with User_03 info , 

debugging show that : 


DataSnapshot ds is loaded with right value of signed in user ( right key and info ) .
uInfo ( the object which carry signed in user info) loaded with right data from database .
uInfo.setName(ds.getValue(UserInformations.class).getName()); = undefined .
I think there is something wrong in arryList size .


the attached screen shot I take it when arrive to breakpoint in line : toastMassege("it's Done") . 
public class AddToDatabase extends AppCompatActivity {
private static final String TAG = "AddToDatabase";
private ListView userInfolist ;
private FirebaseAuth mAuth;
private FirebaseAuth.AuthStateListener mAuthListener;
String userId;
UserInformations uInfo =new UserInformations();
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_add_to_database);

    userInfolist = (ListView) findViewById(R.id.userInfolist);
    mAuth = FirebaseAuth.getInstance();
    FirebaseDatabase mFirebaseDatabase = FirebaseDatabase.getInstance();
    DatabaseReference myRef = mFirebaseDatabase.getReference();
    FirebaseUser user = mAuth.getCurrentUser();
    userId = user.getUid();

    mAuthListener = new FirebaseAuth.AuthStateListener() {
        @Override
        public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
            FirebaseUser user = firebaseAuth.getCurrentUser();
            if (user != null) {
                Log.d(TAG, "onAuthStateChanged:signed_in:" + user.getUid());
                toastMassege(" You are successfly signed in with " + 
                user.getEmail());
            } else {
                Log.d(TAG, "onAuthStateChanged:signed_out");
                toastMassege(" You are successfly signed out ");
            }
        }
    };

    myRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
          showData(dataSnapshot);
        }
        @Override
        public void onCancelled(DatabaseError error) {
        }
    });
}
private void showData(DataSnapshot dataSnapshot) {
  for(DataSnapshot ds : dataSnapshot.getChildren()){

      uInfo.setName(ds.getValue(UserInformations.class).getName());
      uInfo.setEmail(ds.getValue(UserInformations.class).getEmail()); 
     uInfo.setPhone_num(ds.getValue(UserInformations.class).getPhone_num());

      ArrayList<String> arrayList=new ArrayList<>();
      int listSize = arrayList.size();
      arrayList.add(uInfo.getName());
      arrayList.add(uInfo.getEmail());
      arrayList.add(uInfo.getPhone_num()); 
      ArrayAdapter<String> adapter =new ArrayAdapter<>(this,android.R.layout.simple_list_item_1,arrayList);
      userInfolist.setAdapter(adapter);
      toastMassege("its Done ");
  }
}
@Override
public void onStart() {
    super.onStart();
    mAuth.addAuthStateListener(mAuthListener);
}
@Override
public void onStop() {
    super.onStop();
    if (mAuthListener != null) {
        mAuth.removeAuthStateListener(mAuthListener);
    }
}
private void toastMassege(String massege) {
    Toast.makeText(this, massege, Toast.LENGTH_SHORT).show();
}

 }
this is class UserInformations
class UserInformations {

public String email,name,phone_num ;
UserInformations() {
}
public String getEmail() {
    return email;
}
public void setEmail(String email) {
    this.email = email;
}
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}
public String getPhone_num() {
    return phone_num;
}
public void setPhone_num(String phone_num) {
    this.phone_num = phone_num;
}
}
解决方案
This is happening because you are have declared the ArrayList<String> arrayList=new ArrayList<>(); inside the for loop. This means that you are creating a new instance of ArrayList class every time you iterate.

In order to solve this, just move the decration outside for loop like this:
private void showData(DataSnapshot dataSnapshot) {
  ArrayList<String> arrayList=new ArrayList<>(); //Moved outside

  for(DataSnapshot ds : dataSnapshot.getChildren()){

      uInfo.setName(ds.getValue(UserInformations.class).getName());
      uInfo.setEmail(ds.getValue(UserInformations.class).getEmail()); 
      uInfo.setPhone_num(ds.getValue(UserInformations.class).getPhone_num());

      int listSize = arrayList.size();
      arrayList.add(uInfo.getName());
      arrayList.add(uInfo.getEmail());
      arrayList.add(uInfo.getPhone_num()); 
      ArrayAdapter<String> adapter =new ArrayAdapter<>(this,android.R.layout.simple_list_item_1,arrayList);
      userInfolist.setAdapter(adapter);
      toastMassege("its Done ");
  }
}


                        
这篇关于无论登录哪个用户，arrayList总是装载来自Firebase数据库的用户信息？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！