无法将String转换为数据类对象-Firebase实时数据库 [英] Can't convert String to data class objects - Firebase realtime database

问题描述

我也阅读了有关同一问题的其他评论，但没有人提到类似我的情况

I have read other comments on this same issue, but none of them has touched on a situation like mine

在我的文章中，下面介绍了数据的结构:

In mine, below describes how the data is structured:

{
   "symbols":{
      "alphabets":{
         "a":{
            "available":true,
            "text":"A",
            "timestamp":1.512686825309134E9
         },
         "b":{
            "available":true,
            "text":"B",
            "timestamp":1.512687248764272E9
         }"NameOfSymbols":"alphabets"
      }
   }
}

*我的显示错误的原因是它无法转换字符串"NameOfSymbols":对数据类中指定的对象使用字母"

*The reason why mine is showing the error is that it can't convert the string "NameOfSymbols" : "alphabets" to the objects as specified in the data class

因此，我可以使用Kotlin

有没有一种方法可以排除那部分children值，而只获得数据类中指定的那一部分?

数据类

data class alphabets(
    val name: Names,
var NameOfSymbols: String? = null) {
    data class Names(

        var available: Boolean? = null,
        var text: String? = null,
        var timestamp: Long? = null) {

    }
}

推荐答案

此结构可能适用于您的情况(未经测试):

This structure might work for your case (untested):

data class Message(
    @PropertyName("symbols") val symbols: Symbols,
)

data class Symbols(
    @PropertyName("alphabets") val alphabets: Alphabets,
)

data class Alphabets(
    @PropertyName("a") val a: Alphabet,
    @PropertyName("b") val b: Alphabet,
    @PropertyName("NameOfSymbols") val nameOfSymbols: String,
)

data class Alphabet(
    @PropertyName("available") val available: Boolean,
    @PropertyName("text") val text: String,
    @PropertyName("timestamp") val timestamp: Long,
)

用法是:

// in your ValueEventListener
override fun onDataChange(snapshot: DataSnapshot) {
    val value = snapshot.getValue<Message>()
}

如果要排除 NameOfSymbols ，则应将其删除，并添加 @IgnoreExtraProperties ，如下所示:

If you want to exclude your NameOfSymbols, you should remove it, and add the @IgnoreExtraProperties, like shown below:

@IgnoreExtraProperties
data class Alphabets(
    @PropertyName("a") val a: Alphabet,
    @PropertyName("b") val b: Alphabet,
)

注意，我使用了这些版本的Firebase数据库:

NOTE, I used these versions of firebase database:

implementation 'com.google.firebase:firebase-database:19.7.0'
implementation 'com.google.firebase:firebase-database-ktx:19.7.0'

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