Android - 无法使用给定的uid从Firebase中检索数据

问题描述

我的Firebase数据库结构是：

p>

我想检索某个用户的全名，当我有它的密钥的时候。

我的代码：
$ b

 public class ProfileActivity扩展了AppCompatActivity的实现View.OnClickListener {
 
 private FirebaseAuth firebaseAuth ; 
私人TextView textView; 
私人按钮logbutton，wantToDeliverButton，lookForButton; 
 private String userName; 
 @Override 
 protected void onCreate（Bundled savedInstanceState）{
 super.onCreate（savedInstanceState）; 
 setContentView（R.layout.activity_profile）; 
 Firebase.setAndroidContext（this）; textView =（TextView）findViewById（R.id.textView2）; 
 Firebase usersRef =新的Firebase（https://myfirstfirebaseauth.firebaseio.com）; 
 firebaseAuth = FirebaseAuth.getInstance（）; 
 if（firebaseAuth.getCurrentUser（）== null）{
 finish（）; 
 startActivity（new Intent（this，LoginActivity.class））; 
} 
 FirebaseUser user = firebaseAuth.getCurrentUser（）; 
 Firebase ref = usersRef.child（User）。child（user.getUid（））; 
 ref.addValueEventListener（new ValueEventListener（）{
 @Override 
 public void onDataChange（DataSnapshot dataSnapshot）{
 userName = dataSnapshot.getValue（User.class）.getFullName（）; 
 
 
 $ b @Override 
 public void onCancelled（FirebaseError firebaseError）{
 
 
}）; 
 textView.setText（welcome+ userName）; 
  

但是它将textView设置为null。我尝试在onDataChange（）方法中放置Toast，但不起作用。它看起来甚至没有进入该方法。
$ b

行 FirebaseUser user = firebaseAuth.getCurrentUser（）; 是正确的，因为如果我写 textView.setText（welcome+ user.getEmail（））; - 我真的得到正确的电子邮件。 b
$ b

如何解决这个问题？我使用正确的听众？我不想在数据库中改变任何东西，只是检索。
$ b

编辑：它去onCancelled（）。

解决方案

您正在混合传统2.5.X Firebase SDK的功能（例如：）和新的9.XX SDK（例如：）。这几乎肯定是失败的秘诀。重做你的代码，只使用新的SDK。 。

My Firebase database structure is:enter image description here

I want to retrieve the full name of some user, when i have its key.

My code:

public class ProfileActivity extends AppCompatActivity implements View.OnClickListener {

private FirebaseAuth firebaseAuth;
private TextView textView;
private Button logbutton,wantToDeliverButton,lookForButton;
private String userName;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_profile);
    Firebase.setAndroidContext(this);textView = (TextView)findViewById(R.id.textView2);
    Firebase usersRef = new Firebase("https://myfirstfirebaseauth.firebaseio.com");
    firebaseAuth = FirebaseAuth.getInstance();
    if (firebaseAuth.getCurrentUser() == null){
        finish();
        startActivity(new Intent(this,LoginActivity.class));
    }
    FirebaseUser user = firebaseAuth.getCurrentUser();
    Firebase ref = usersRef.child("User").child(user.getUid());
    ref.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            userName = dataSnapshot.getValue(User.class).getFullName();

        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {

        }
    });
    textView.setText("welcome "+userName);

But it set the textView to null. I try to put Toast inside the onDataChange() method, but it doesn't work. It seems it doesn't even get inside the method.

The line FirebaseUser user = firebaseAuth.getCurrentUser(); is correct because if i'm writing textView.setText("welcome "+ user.getEmail()); - i realy get the correct email.

How to solve this? Am i using the correct listener? I don't want to change anything in the database, just retrieve.

Edit: it goes to onCancelled().

解决方案

You're mixing capabilities from the legacy 2.5.X Firebase SDK (Example: Firebase.setAndroidContext()) and the new 9.X.X SDK (Example: FirebaseAuth.getInstance()). That is almost certainly a recipe for failure. Rework your code to use only the new SDK. The Setup Guide is here.

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