将Firebase数据快照反序列化为Kotlin数据类 [英] Deserialize a Firebase Data-Snapshot to a Kotlin data class
问题描述
我有一个如下的Kotlin数据类
Hi I have a Kotlin data class as follows
data class User (
@get:Exclude val gUser: Boolean,
@get:Exclude val uid: String,
@get:PropertyName("display_name") val displayName: String,
@get:PropertyName("email") val email: String,
@get:PropertyName("account_picture_url") val accountPicUrl: String,
@get:PropertyName("provider") val provider: String
)
我能够序列化该对象而没有任何问题.但是在执行Firebase查询时,我无法反序列化对象.目前,这就是我正在获取数据的步骤
I am able to serialize the object without an issues. But i'm having trouble deserializing the object when doing a firebase query. Currently this is what i'm doing to get the data
_firebaseReference.child(getString(R.string.firebase_users_key)).child(user.uid)
.setValue(user).addOnCompleteListener{
_firebaseReference.child("users").child(user.uid)
.addListenerForSingleValueEvent(object : ValueEventListener {
override fun onCancelled(p0: DatabaseError) {
}
override fun onDataChange(p0: DataSnapshot) {
if (p0.exists()) {
val userHash = p0.value as HashMap<*, *>
var currentUser: User
if (userHash[getString(R.string.provider_key)]
!= getString(R.string.provider_google)) {
currentUser = User(false, p0.key!!,
userHash["display_name"].toString(),
userHash["email"].toString(),
userHash["account_picture_url"].toString(),
userHash["provider"].toString())
} else {
currentUser = User(true, p0.key!!,
userHash["display_name"].toString(),
userHash["email"].toString(),
userHash["account_picture_url"].toString(),
userHash["provider"].toString())
}
}
}
})
}
这只是我正在练习我的Kotlin的测试项目,但这是我想弄清楚的东西.
This is only a test project that i'm working on to practice my Kotlin, but this is something I would like to figure out.
如果我做错了,请告诉我,任何建议将不胜感激
If i'm doing it completely wrong please let me know, any advise would be greatly appreciated
谢谢
推荐答案
Firebase需要一个空的构造函数才能反序列化对象:
Firebase needs an empty constructor to be able to deserialize the objects:
data class User(
@Exclude val gUser: Boolean,
@Exclude val uid: String,
@PropertyName("display_name") val displayName: String,
@PropertyName("email") val email: String,
@PropertyName("account_picture_url") val accountPicUrl: String,
@PropertyName("provider") val provider: String
) {
constructor() : this(false, "", "", "", "", "")
}
您可以像这样声明它并提供一些默认值以调用主构造函数,也可以为所有参数声明默认值:
You can either declare it like so and provide some default values to be able to call the primary constructor or you can declare default values for all your parameters:
data class User (
@Exclude val gUser: Boolean = false,
@Exclude val uid: String = "",
@PropertyName("display_name") val displayName: String = "",
@PropertyName("email") val email: String = "",
@PropertyName("account_picture_url") val accountPicUrl: String = "",
@PropertyName("provider") val provider: String = ""
)
然后将为您创建各种构造函数,包括一个空的构造函数.
Then various constructors will be created for you, including an empty constructor.
如果序列化存在问题,可能是由于ide生成的getter和setter引起的,请尝试使用@get和@set批注来增强它们:
If there's a problem with serialization there might be because of the getters and setters generated by the ide, try reinforcing them with @get and @set annotations:
data class User (
@Exclude val gUser: Boolean = false,
@Exclude val uid: String = "",
@set:PropertyName("display_name")
@get:PropertyName("display_name")
var displayName: String = "",
@PropertyName("email") val email: String = "",
@set:PropertyName("account_picture_url")
@get:PropertyName("account_picture_url")
var accountPicUrl: String = "",
@PropertyName("provider") val provider: String = ""
)
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