Question

我有这个POJO：

public class Person{
    private String id;
    private List phoneNumbers=new ArrayList<>();
    private Map<String,String> fcmTokens;
    //getters + Setters + default constructor are present
}

在活动中：我尝试使用以下代码将此对象保存到Firebase Realtime DB，但仅保存了String id值！我在这里想念什么？

Person p= new Person();
p.setUid("123");
List<String> list=new ArrayList<>();
list.add("123);
list.add("23");
p.setPhoneNumbers(list);
Map<String,String> map=new HashMap<>();
map.put("asdf","asdfas");
map.put("23","@3r");
p.setFcmTokens(map);
mPersonNodeReference.setValue(p);

Answer 1

检查是否没有添加调用DataSnapshot.getValue（User.class）所需的Default构造函数

public class Person{
       public Person() {

    }
}

备注：变量命名不一致。

Answer 2

要在Firebase中添加此类嵌套字段，应远离数组，并根据官方文档使用Map。因此，对于您的情况，应该是

Person p = new Person();
p.setUid("123");
//List<String> list = new ArrayList<>();   //this will not work unless you push a new key for every value added to the list
//list.add("123");
//list.add("23");
Map<String,String> mapPhoneNumbers = new HashMap<>();
mapPhoneNumbers.put("1","123");
mapPhoneNumbers.put("2","23");
p.setPhoneNumbers(mapPhoneNumbers);
Map<String,String> map = new HashMap<>();
p.setFcmTokens(map)   //not sure what barber is?
mPersonNodeReference.setValue(p);  //did you mean p?

Answer 3

A。活动中：

@Override
public void onCreate() {
    super.onCreate();
    FirebaseApp.initializeApp(this);
    //your code.
}

B。应用程序级build.gradle：

apply plugin: 'com.android.application'

    enter code here

android {
  // ...
}

dependencies {
  // ...
  implementation 'com.google.firebase:firebase-core:16.0.1'
  implementation 'com.google.firebase:firebase-database:16.0.1'
}

// ADD THIS AT THE BOTTOM
apply plugin: 'com.google.gms.google-services'

C。项目级build.gradle：

dependencies {
    classpath 'com.android.tools.build:gradle:3.3.0'
    classpath 'com.google.gms:google-services:4.0.0'
    /*classpath 'com.google.gms:google-services:4.1.0' <-- do not use this version*/
}

Firebase Realtime数据库未保存包含列表或地图属性的POJO

3 个答案: