讀取從Firebase的ChildEventListener（）獲取的DatasnapShot內容的問題

我無法從dataSnapshot中提取字段值。讀取從Firebase的ChildEventListener（）獲取的DatasnapShot內容的問題

下面是代碼：

ChildEventListener userListener = new ChildEventListener() { 
    @Override 
    public void onChildAdded(DataSnapshot dataSnapshot, String s) { 
     Log.d(TAG,"users count:"+dataSnapshot.getChildrenCount()+" users"); 

     for(DataSnapshot receivedSnapshot:dataSnapshot.getChildren()) { 
      Log.d(TAG,"received Snapshot"+receivedSnapshot); 
      Toast.makeText(getBaseContext(),"received Snapshot"+receivedSnapshot,Toast.LENGTH_LONG).show(); 
      Person person = receivedSnapshot.getValue(Person.class)// Getting the error for this line. 

      Log.i(TAG,"receivedSnapshot:"+person.toString()); 

     } 
    } 

    @Override 
    public void onChildChanged(DataSnapshot dataSnapshot, String s) { 

    } 

    @Override 
    public void onChildRemoved(DataSnapshot dataSnapshot) { 

    } 

    @Override 
    public void onChildMoved(DataSnapshot dataSnapshot, String s) { 

    } 

    @Override 
    public void onCancelled(DatabaseError databaseError) { 

    } 
}; 

dataBase = FirebaseDatabase.getInstance(); 
DatabaseReference userTable = dataBase.getReference("users"); 
userTable.addChildEventListener(userListener);

這裏是logcat的：

Process: com.example.raghavkishan.wealthmanagement, PID: 23843 
Theme: themes:{default=overlay:system, iconPack:website.leifs.delta, fontPkg:system, com.android.systemui=overlay:system, com.android.systemui.navbar=overlay:system} 
com.google.firebase.database.DatabaseException: Can't convert object of type java.lang.String to type com.example.raghavkishan.wealthmanagement.Person

我的Person類：

private String personName; 
private String personEmail; 
private int phoneNumber; 
private String dateOfBirth; 
private String city; 
private String state; 
private String country; 
private String groupId; 

public Person(String personName,String personEmail,int phoneNumber,String dateOfBirth,String city,String state,String country,String groupId){ 
    this.personName = personName; 
    this.personEmail = personEmail; 
    this.phoneNumber = phoneNumber; 
    this.dateOfBirth = dateOfBirth; 
    this.city = city; 
    this.state = state; 
    this.country = country; 
    this.groupId = groupId; 

}[![enter image description here][1]][1]

圖像包含數據庫結構。用戶的UID是節點的關鍵。

我使用Person類的一個對象把數據上傳到數據庫的火力點。但在檢索它時，我遇到了上述錯誤。

1）我犯了什麼錯誤？

2）任何替代方法？

來源

2017-05-06 Raghav Kishan

請發佈Person類定義和firebase節點 –

請添加您的數據庫結構和您的pojo。 –

@SushobhNadiger我已更新人員類和數據庫結構 –

您的DatabaseReference是錯誤的。你需要改變這一行：

DatabaseReference userTable = dataBase.getReference("users");

與

DatabaseReference userTable = dataBase.getReference("users").child(userId);

的問題是，你缺少一個孩子，孩子userId。 userId是由push()方法生成的唯一ID。

希望它有幫助。

來源

2017-05-08 09:04:05

讀取從Firebase的ChildEventListener（）獲取的DatasnapShot內容的問題

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