如何在kotlin中添加加载对话框

Question

当我的应用程序加载数据json url时，我试图添加加载对话框，因为在午餐应用程序时显示空白屏幕，直到数据到来

这是代码

inner class Dep : AsyncTask<String, String, String>(){

//        for build connection
override fun doInBackground(vararg url: String?): String{
var text : String
val connection = URL(url[0]).openConnection() as HttpURLConnection
try {
connection.connect()
text = connection.inputStream.use { it.reader().use{reader -> reader.readText()} }

} finally{
connection.disconnect()
}
return text
}
override fun onPostExecute(result: String?) {
val progressDialog = ProgressDialog(Context,this@MainActivity)
progressDialog.setMessage("loading")
progressDialog.setCancelable(false)
progressDialog.show()
super.onPostExecute(result)
handleJson(result)
if (progressDialog != null)
progressDialog.dismiss();
}
private fun handleJson (jsonString: String?){
val jsonObj = JSONObject(jsonString)
val result = jsonObj.getJSONObject("result")
val response = result.getJSONObject("response")
val airport = response.getJSONObject("airport")
val pluginData = airport.getJSONObject("pluginData")
val schedule = pluginData.getJSONObject("schedule")
val arrivals = schedule.getJSONObject("departures")
//        val data = arrivals.getJSONObject("data")
val jsonArray = JSONArray(arrivals.get("data").toString())
val list =  ArrayList<FlightShdu>()
var x = 0
while (x < jsonArray.length()){
val jsonObject = jsonArray.getJSONObject(x)

list.add(FlightShdu(
jsonObject.getJSONObject("flight").getJSONObject("identification").getJSONObject("number").getString("default"),
jsonObject.getJSONObject("flight").getJSONObject("airline").getString("name"),
jsonObject.getJSONObject("flight").getJSONObject("status").getString("text"),
jsonObject.getJSONObject("flight").getJSONObject("airline").getJSONObject("code").getString("icao"),
jsonObject.getJSONObject("flight").getJSONObject("time").getJSONObject("scheduled").getString("departure")

))

x++
}
list.forEach(::println)
val adapter = ListAdapte(this@MainActivity,list)
flight_dep_list.adapter = adapter
}
//    for get items from json api
override fun onProgressUpdate(vararg values: String?) {
}

}

l在onPostExecute中使用了进度对话框代码

override fun onPostExecute(result: String?) {
val progressDialog = ProgressDialog(Context,this@MainActivity)
progressDialog.setMessage("loading")
progressDialog.setCancelable(false)
progressDialog.show()
super.onPostExecute(result)
handleJson(result)
if (progressDialog != null)
progressDialog.dismiss();
}

我得到了红线错误

classifier 'Context' dose not have a companion object , and thus must be initialized here

我需要添加进度对话框xml吗？

Answer 1

您需要像lateinit var context2:Context这样的Context实例，然后context2=container！！。context，然后使用ProgressDialog 传递context2