從多個節點

Question

一個火力點數據庫檢索數據，我正在嘗試從用戶和時間的數據。但是我無法訪問數據，它並不真正訪問數據庫。

protected void onCreate(@Nullable Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_balance); 

    mFirebaseDatabase=FirebaseDatabase.getInstance(); 
    cashRef=mFirebaseDatabase.getReference().child("ASSETS").child("cash_at_bank"); 


    TextView view=(TextView)findViewById(R.id.view); 
    view.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View view) { 

      cashRef.addListenerForSingleValueEvent(new ValueEventListener() { 
       @Override 
       public void onDataChange(DataSnapshot dataSnapshot) { 

        int time=dataSnapshot.getValue(int.class); 
        int values =dataSnapshot.getValue(int.class); 

       } 

       @Override 
       public void onCancelled(DatabaseError databaseError) { 

       } 
      }); 

     } 
    }); 

Answer 1

要獲得time，請使用如下代碼：

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference(); 
DatabaseReference cashAtBankRef = rootRef.child("ASSETS").child("Cash at bank"); 
ValueEventListener eventListener = new ValueEventListener() { 
    @Override 
    public void onDataChange(DataSnapshot dataSnapshot) { 
     for(DataSnapshot ds : dataSnapshot.getChildren()) { 
      Long time = ds.child("time").child("time").getValue(Long.class); 
      Log.d("TAG", time + ""); 
     } 
    } 

    @Override 
    public void onCancelled(DatabaseError databaseError) {} 
}; 
cashAtBankRef.addListenerForSingleValueEvent(eventListener); 

輸出將是：

150555043995 
//and so on