英文:
Getting this error - java.lang.llegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line1 column 2 path $
问题
我也尝试过使用DiffUtil进行API调用，但错误仍然存在，我不断收到此错误：java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path $，有人可以帮助吗？我正在使用Kotlin。
这是模型类：
data class BeerList(
val list: List<BeerListItem>
) {
data class BeerListItem(
val alcohol: String,
val blg: String,
val brand: String,
val hop: String,
val ibu: String,
val id: Int,
val malts: String,
val name: String,
val style: String,
val uid: String,
val yeast: String
)
}
这是适配器类：
class BeeraAdapter(private val listItem: List<BeerList.BeerListItem>) : RecyclerView.Adapter<BeeraAdapter.ViewHolderBeer>() {
// ... （其余部分保持不变）
}
这是MainActivity中的API调用：
class MainActivity : AppCompatActivity() {
// ... （其余部分保持不变）
override fun onResponse(call: Call<BeerList>, response: Response<BeerList>) {
val beers = response.body()
val list = beers?.list
adapter = BeeraAdapter(list ?: emptyList())
binding.recyclerView.adapter = adapter
}
// ... （其余部分保持不变）
}
英文:
I've also tried to do this api calling by using DiffUtil but the error remains the same and i keep getting this error java.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path $ can someone help i'm using kotlin
This is model class
package com.example.beercatalog.model
data class BeerList(
val list : List<BeerListItem>
) {
data class BeerListItem(
val alcohol: String,
val blg: String,
val brand: String,
val hop: String,
val ibu: String,
val id: Int,
val malts: String,
val name: String,
val style: String,
val uid: String,
val yeast: String
)
}
This is adapter class
package com.example.beercatalog.adapter
import android.view.LayoutInflater
import android.view.ViewGroup
import androidx.recyclerview.widget.RecyclerView
import com.example.beercatalog.databinding.ListItemBinding
import com.example.beercatalog.model.BeerList
class BeeraAdapter(private val listItem : List<BeerList.BeerListItem>) : RecyclerView.Adapter<BeeraAdapter.ViewHolderBeer>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolderBeer {
val binding = ListItemBinding.inflate(LayoutInflater.from(parent.context),parent ,false)
return ViewHolderBeer(binding)
}
override fun getItemCount(): Int {
return listItem.size
}
override fun onBindViewHolder(holder: ViewHolderBeer, position: Int) {
val count = listItem[position]
holder.binding.beerName.text = count.name
holder.binding.beerBrandName.text = count.brand
holder.binding.alcoholperc.text = count.alcohol
}
class ViewHolderBeer(var binding : ListItemBinding) : RecyclerView.ViewHolder(binding.root){
}
}
This is api calling in mainactivity
package com.example.beercatalog
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Toast
import com.example.beercatalog.adapter.BeeraAdapter
import com.example.beercatalog.api.BeerRetrofit
import com.example.beercatalog.databinding.ActivityMainBinding
import com.example.beercatalog.model.BeerList
import retrofit2.Call
import retrofit2.Callback
import retrofit2.Response
class MainActivity : AppCompatActivity() {
lateinit var binding : ActivityMainBinding
lateinit var adapter : BeeraAdapter
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityMainBinding.inflate(layoutInflater)
setContentView(binding.root)
val url = "https://random-data-api.com/api/v2/beers?size=10&response_type=json"
BeerRetrofit().getInstance()!!
.beerAPI
.getBeers(url)
.enqueue(object : Callback<BeerList>{
override fun onResponse(call: Call<BeerList>, response: Response<BeerList>) {
val beers = response.body()
val list = beers!!.list
adapter = BeeraAdapter(list)
binding.recyclerView.adapter = adapter
}
override fun onFailure(call: Call<BeerList>, t: Throwable) {
Toast.makeText(applicationContext, t.localizedMessage, Toast.LENGTH_SHORT)
.show()
}
})
}
}
Please explain and solve this error
答案1
得分: 1
I believe that the problem is happening in json parsing.
Following the url you've linked I see actually an array of objects, ie [{...}, {...}].
However, you're trying to parse BeerList. The parser is looking for a top level json object with a field list in it, which can be represented as an array. In other words, the parser is looking for {"list": [{...}, ... {...}]}.
To fix your issue you need to change getBeers(url) method signature (this should be a retrofit interface). Instead of returning BeerList from it, you need to return List<BeerListItem>.
英文:
I believe that the problem is happening in json parsing.
Following the url you've linked I see actually an array of objects, ie [{...}, {...}].
However, you're trying to parse BeerList. The parser is looking for a top level json object with a field list in it, which can be represented as array. In other words, the parser is looking for {"list": [{...}, ... {...}]}.
To fix your issue you need to change getBeers(url) method signature (this should be a retrofit interface). Instead of returning BeerList from it, you need to return List<BeerListItem>.
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