android - 获取空值作为响应
问题描述
我正在尝试从https://www.reddit.com/r/popular/.rss获取响应并映射到 Android 中的 Kotlin POJO 类。但是当我记录该类别的标签值时,得到空值。对于标题,我得到了作为流行链接的响应值。
这是实体类 FeedX:-
@Root(name = "feed", strict = false)
class FeedX {
@set: Element(name = "category")
@get: Element(name = "category")
var category: Category? = null
val entry: List<Entry>? = null
val id: String? = null
val link: List<LinkX>? = null
@set: Element(name = "title")
@get: Element(name = "title")
var title: String? = null
val updated: String? = null
}
类别类别:-
@Root(name = "category", strict = false)
class Category {
@set: Element(required = false, name = "_label")
@get: Element(required = false, name = "_label")
var _label: String? = null
val _term: String? = null
}
这是 Api 接口:-
interface FeedApi {
@GET("{type}/.rss")
fun getPopularFeeds(
@Path("type") type: String?
): Call<FeedX>?
}
这是主要活动:-
class MainActivity : AppCompatActivity() {
private val BASE_URL = "https://www.reddit.com/r/"
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val retrofit = Retrofit.Builder()
.baseUrl(BASE_URL)
.addConverterFactory(SimpleXmlConverterFactory.create())
.build()
val service = retrofit.create(FeedApi::class.java)
service.getPopularFeeds("popular")?.enqueue(object : Callback<FeedX> {
override fun onFailure(call: Call<FeedX>, t: Throwable) {
Log.d("Response Failed", "${t.localizedMessage}")
}
override fun onResponse(call: Call<FeedX>, response: Response<FeedX>) {
if (response.isSuccessful) {
Log.d("Response Success", "${response.body()!!.title}") // for this I am getting value
Log.d("Response Success", "${response.body()!!.category?._label}") // always getting null value
} else {
Log.d("Response Failed jg", "${response.errorBody()}")
}
}
})
}
}
解决方案
这是因为包含标签不title
包含的值。category
请参阅下面的区别。
<title>popular links</title>
<category term="AskReddit" label="r/AskReddit"/>
如您所见,category
标签是自动关闭的。
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