fatel error check internet connection in kotlin - kotlin

Question

my app working fine any without problem , i used AsyncTask to get data json and every thing is fine . i want to add code to check internet connection in my app and i put code under onCreate in main activity .
val cm = baseContext.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
val networkInfo = cm.activeNetworkInfo
if (networkInfo != null && networkInfo.isConnected){
if (networkInfo.type == ConnectivityManager.TYPE_WIFI){
Toast.makeText(baseContext,"wifi",Toast.LENGTH_SHORT).show()
}
if (networkInfo.type == ConnectivityManager.TYPE_MOBILE){
Toast.makeText(baseContext,"MOBILE",Toast.LENGTH_SHORT).show()
}
}else {
Toast.makeText(baseContext,"MOBILE",Toast.LENGTH_SHORT).show()
this.finish()
}
when l put the phone on airplan mode and launching app he is stop working . and crash .
console log
E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
Process: com.iraqairoirt.iraqairports, PID: 10868
main activity
package com.iraqairoirt.iraqairports
import android.annotation.SuppressLint
import android.content.Context
import android.content.DialogInterface
import android.os.AsyncTask
import android.os.Bundle
import android.support.design.widget.NavigationView
import android.support.v4.view.GravityCompat
import android.support.v7.app.ActionBarDrawerToggle
import android.support.v7.app.AlertDialog
import android.support.v7.app.AppCompatActivity
import android.view.Menu
import android.view.MenuItem
import android.widget.TextView
import com.iraqairoirt.iraqairports.BaghdadAirport.ListAdapteArr
import com.iraqairoirt.iraqairports.BaghdadAirport.ListAdapteDep
import kotlinx.android.synthetic.main.activity_main.*
import kotlinx.android.synthetic.main.content_main.*
import kotlinx.android.synthetic.main.fragment_baghdada_arrivel.*
import kotlinx.android.synthetic.main.fragment_baghdada_dep.*
import org.json.JSONArray
import org.json.JSONObject
import java.net.HttpURLConnection
import java.net.URL
import android.widget.Toast
import android.content.Intent
import android.content.IntentFilter
import android.net.ConnectivityManager
import android.net.NetworkInfo
import android.support.design.widget.Snackbar
import com.iraqairoirt.iraqairports.BaghdadAirport.FlightsArrivelBeforBGW
import com.iraqairoirt.iraqairports.BaghdadAirport.FlightsDepBeforBGW
class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val url = "airport.json"
Arr().execute(url)
setSupportActionBar(toolbar)
val fragmentAdapter = MyPagerAdapter(supportFragmentManager)
viewpager_main.adapter = fragmentAdapter
sliding_tabs.setupWithViewPager(viewpager_main)
val toggle = ActionBarDrawerToggle(
this, drawer_layout, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close
)
drawer_layout.addDrawerListener(toggle)
toggle.syncState()
nav_view.setNavigationItemSelectedListener(this)
val cm = baseContext.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
val networkInfo = cm.activeNetworkInfo
if (networkInfo != null && networkInfo.isConnected){
if (networkInfo.type == ConnectivityManager.TYPE_WIFI){
Toast.makeText(baseContext,"wifi",Toast.LENGTH_SHORT).show()
}
if (networkInfo.type == ConnectivityManager.TYPE_MOBILE){
Toast.makeText(baseContext,"MOBILE",Toast.LENGTH_SHORT).show()
}
}else {
Toast.makeText(baseContext,"MOBILE",Toast.LENGTH_SHORT).show()
this.finish()
}
}
// full class for json api
inner class Arr : AsyncTask<String, String, String>() {
val progressDialog = AlertDialog.Builder(this#MainActivity)
val dialogView = layoutInflater.inflate(R.layout.progress_dialog, null)
val message = dialogView.findViewById<TextView>(R.id.message_id)
val dialog = progressDialog.create()
override fun onPreExecute() {
super.onPreExecute()
dialog.setMessage("يرجى الانتظار")
dialog.setCancelable(false)
dialog.show()
}
// 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?) {
super.onPostExecute(result)
handleJson(result)
dialog.dismiss();
}
override fun onProgressUpdate(vararg text: String?) {
}
#SuppressLint("WrongViewCast")
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("arrivals")
// weather data
val weather = pluginData.getJSONObject("weather")
val mater = weather.getString("metar")
// MaterText.text=mater
// 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("short"),
jsonObject.getJSONObject("flight").getJSONObject("status").getJSONObject("generic").getJSONObject(
"status"
).getString("text"),
jsonObject.getJSONObject("flight").getJSONObject("airline").getJSONObject("code").getString("icao"),
jsonObject.getJSONObject("flight").getJSONObject("time").getJSONObject("scheduled").getString("arrival"),
jsonObject.getJSONObject("flight").getJSONObject("airport").getJSONObject("origin").getJSONObject(
"code"
).getString("iata"),
jsonObject.getJSONObject("flight").getJSONObject("aircraft").getJSONObject("model").getString("code"),
// for more information
jsonObject.getJSONObject("flight").getJSONObject("time").getJSONObject("real").getString("departure"),
jsonObject.getJSONObject("flight").getJSONObject("time").getJSONObject("estimated").getString("arrival"),
// jsonObject.getJSONObject("flight").getJSONObject("time").getJSONObject("estimated").getString("arrival"),
jsonObject.getJSONObject("flight").getJSONObject("aircraft").getString("registration"),
jsonObject.getJSONObject("flight").getJSONObject("status").getJSONObject("generic").getJSONObject(
"status"
).getString("diverted"),
arrivals.getString("timestamp"),
jsonObject.getJSONObject("flight").getJSONObject("status").getString("icon")
)
)
x++
}
list.forEach(::println)
var adapter = ListAdapteArr(this#MainActivity, list)
flight_arrivel_list.adapter = adapter
}
}
override fun onBackPressed() {
if (drawer_layout.isDrawerOpen(GravityCompat.START)) {
drawer_layout.closeDrawer(GravityCompat.START)
} else {
super.onBackPressed()
}
}
override fun onCreateOptionsMenu(menu: Menu): Boolean {
// Inflate the menu; this adds items to the action bar if it is present.
menuInflater.inflate(R.menu.main, menu)
return true
}
override fun onOptionsItemSelected(item: MenuItem): Boolean {
val id = item.itemId
//noinspection SimplifiableIfStatement
if (id == R.id.flightarrbeforbgw) {
val intent = Intent(this, FlightsArrivelBeforBGW::class.java)
this.startActivity(intent)
return true
}
if (id == R.id.flightdepbefrobgw) {
val intent = Intent(this, FlightsDepBeforBGW::class.java)
this.startActivity(intent)
return true
}
//
// if (id == R.id.searchflights) {
// Toast.makeText(this, "Android Menu is Clicked", Toast.LENGTH_LONG).show()
// return true
// }
return super.onOptionsItemSelected(item)
}
override fun onNavigationItemSelected(item: MenuItem): Boolean {
// Handle navigation view item clicks here.
when (item.itemId) {
R.id.nav_camera -> {
// Handle the camera action
}
R.id.nav_gallery -> {
}
R.id.nav_slideshow -> {
}
R.id.nav_manage -> {
}
R.id.nav_share -> {
}
R.id.nav_send -> {
}
}
drawer_layout.closeDrawer(GravityCompat.START)
return true
}
}

Answer 1

to avoid fatal error and crash when there is not internet connection ,my mistake is i should put execute() url inside code of check internet connection
val cm = baseContext.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
val networkInfo = cm.activeNetworkInfo
if (networkInfo != null && networkInfo.isConnected){
if (networkInfo.type == ConnectivityManager.TYPE_WIFI){
val url = "airport.json"
Arr().execute(url)
}
if (networkInfo.type == ConnectivityManager.TYPE_MOBILE){
val url = "airport.json"
Arr().execute(url)
}
}else {
val builder = AlertDialog.Builder(this)
builder.setTitle("No internet Connection")
builder.setMessage("Please turn on internet connection to continue")
builder.setNegativeButton(
"close"
) { dialog, button -> this.finish() }
val alertDialog = builder.create()
alertDialog.show()
}
now my app working fine =)