Android中基于RegId从Firebase实时数据库更新数据失败问题

我需要基于用户保存的RegId（作为子字符串存储，而非通过Auth认证）从Firebase实时数据库检索数据并更新对应值，但当前编写的updateDatatoFirebase方法无法完成更新操作。

当前更新数据代码 #

private void updateDatatoFirebase(String regid, String doctor_name, String city,String speciality) {
    Map<String, Object> update=new HashMap<>();
    update.put("doctor",doctor_name);
    update.put("city",city);
    update.put("speciality",speciality);

    DatabaseReference dbref=FirebaseDatabase.getInstance().getReference();
    dbref.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot snapshot) {
            
            for (DataSnapshot ds : snapshot.getChildren()){
                key = snapshot.getKey();


                if(checkid.equalsIgnoreCase(regid))
                {
                    dbref.updateChildren(update);
                    Toast.makeText(need_help.this, "Data in Database updated", Toast.LENGTH_SHORT).show();
                }

                else
                    Toast.makeText(need_help.this, "No such id found", Toast.LENGTH_SHORT).show();
               
            }
        }

        @Override
        public void onCancelled(@NonNull DatabaseError error) {
           
            Toast.makeText(need_help.this, "Fail to add data " + error, Toast.LENGTH_SHORT).show();
        }
    });
}

数据添加代码 #

private void addDatatoFirebase(String regid, String doctor_name, String city,String speciality) {
    
    root=firebaseDatabase.getReference().child("RegId").child(regid);
    HashMap<String, String> usermap=new HashMap<>();
    usermap.put("doctor",doctor_name);
    usermap.put("city",city);
    usermap.put("speciality",speciality);
    root.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot snapshot) {
           
            root.push().setValue(usermap);

            
            Toast.makeText(need_help.this, "Data in Database updated", Toast.LENGTH_SHORT).show();
        }

        @Override
        public void onCancelled(@NonNull DatabaseError error) {
          
            Toast.makeText(need_help.this, "Fail to add data " + error, Toast.LENGTH_SHORT).show();
        }
    });
}

问题分析 #

• 根引用定位错误：更新方法直接使用数据库根节点，而数据实际存储在RegId/regid/随机pushId路径下，未定位到正确子节点。
• 循环逻辑错误：循环中错误获取根节点key而非当前子节点ds的key；checkid变量未定义，缺少RegId匹配逻辑。
• 更新路径错误：调用dbref.updateChildren(update)会更新根节点字段，而非目标子节点，导致数据更新到错误位置。
• 添加数据冗余：添加时无需监听快照即可调用push()，且push()生成的随机ID会让每个RegId下存在多个子节点，增加更新复杂度。

修复方案 #

优化添加数据方法（可选，简化结构） #

若每个RegId仅需存储一条数据，可移除push()，直接写入RegId节点：

private void addDatatoFirebase(String regid, String doctor_name, String city,String speciality) {
    DatabaseReference root = FirebaseDatabase.getInstance().getReference().child("RegId").child(regid);
    HashMap<String, String> usermap = new HashMap<>();
    usermap.put("doctor", doctor_name);
    usermap.put("city", city);
    usermap.put("speciality", speciality);
    
    root.setValue(usermap)
        .addOnSuccessListener(aVoid -> 
            Toast.makeText(need_help.this, "Data added successfully", Toast.LENGTH_SHORT).show())
        .addOnFailureListener(e -> 
            Toast.makeText(need_help.this, "Failed to add data: " + e.getMessage(), Toast.LENGTH_SHORT).show());
}

修复更新数据方法 #

场景1：每个RegId对应一条数据（无随机pushId）

直接通过路径定位目标节点并更新：

private void updateDatatoFirebase(String regid, String doctor_name, String city,String speciality) {
    Map<String, Object> update = new HashMap<>();
    update.put("doctor", doctor_name);
    update.put("city", city);
    update.put("speciality", speciality);

    DatabaseReference targetRef = FirebaseDatabase.getInstance().getReference()
        .child("RegId").child(regid);
    
    targetRef.updateChildren(update)
        .addOnSuccessListener(aVoid -> 
            Toast.makeText(need_help.this, "Data updated successfully", Toast.LENGTH_SHORT).show())
        .addOnFailureListener(e -> 
            Toast.makeText(need_help.this, "Update failed: " + e.getMessage(), Toast.LENGTH_SHORT).show());
}

场景2：每个RegId下有多个随机pushId子节点

遍历RegId下的子节点，找到匹配项后更新：

private void updateDatatoFirebase(String regid, String doctor_name, String city,String speciality) {
    Map<String, Object> update = new HashMap<>();
    update.put("doctor", doctor_name);
    update.put("city", city);
    update.put("speciality", speciality);

    DatabaseReference regIdRef = FirebaseDatabase.getInstance().getReference().child("RegId").child(regid);
    
    regIdRef.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot snapshot) {
            boolean found = false;
            for (DataSnapshot ds : snapshot.getChildren()) {
                // 根据实际数据结构调整匹配逻辑，比如从子节点获取regid字段
                String childRegId = ds.getKey(); 
                if (regid.equalsIgnoreCase(childRegId)) {
                    ds.getRef().updateChildren(update);
                    Toast.makeText(need_help.this, "Data updated", Toast.LENGTH_SHORT).show();
                    found = true;
                    break;
                }
            }
            if (!found) {
                Toast.makeText(need_help.this, "No such id found", Toast.LENGTH_SHORT).show();
            }
        }

        @Override
        public void onCancelled(@NonNull DatabaseError error) {
            Toast.makeText(need_help.this, "Update failed: " + error.getMessage(), Toast.LENGTH_SHORT).show();
        }
    });
}

内容的提问来源于stack exchange，提问作者Raunak Seth