How do I maintain my app running and doing the same thing without the app´s window opened? - android-studio

Question

It's probably pretty obvious, but I'm completely new to programming or asking a question at stackoverflow, so I apologize in advance if I can't explain myself properly. Also, there are some parts I have no idea what they are for anymore since the code is basically a mix of tutorials.
What I need the app to do is for it to keep doing what it's doing (the handler part), but while it's is closed (not minimized). But instead of changing the background, I need it to send a notification instead.
In other words, every 10 minutes, if the value of temperBU is 19, I get a notification even if the app is closed.
For that, if I'm not mistaken, what I need is a service, but I don't understand what type is better for this situation. I tried some tutorials, but nothing seems to work, and if it's possible to start the service as soon as the app gets started.
public class MainActivity extends AppCompatActivity {
ConstraintLayout layout;
class Weather extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... address) {
try {
URL url = new URL(address[0]);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.connect();
InputStream is = connection.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
int data = isr.read();
String content = "";
char ch;
while (data != -1) {
ch = (char) data;
content = content + ch;
data = isr.read();
}
Log.i("Content", content);
return content;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String content;
Weather weather = new Weather();
{
{
try {
content = weather.execute("https://api.openweathermap.org/data/2.5/weather?q=budapest,hu&units=metric&appid=ce2fd10cdcc8ab209f979f6a41c27cfe").get();
JSONObject jsonObject = new JSONObject(content);
String mainData = jsonObject.getString("main");
Log.i("mainData", mainData);
JSONObject object = new JSONObject(mainData);
Double temp = object.getDouble("temp");
Log.i("temp", String.valueOf(temp));
int temperBU = (int) Math.round(temp);
Log.i("temperBU", String.valueOf(temperBU));
layout = findViewById(R.id.hs_n);
if (temperBU == 19)
layout.setBackgroundResource(R.drawable.hungry_summer_premium_yes_simple);
else layout.setBackgroundResource(R.drawable.hungry_summer_premium_no_simple);
Handler handler = new Handler();
Runnable r = new Runnable() {
public void run() {
String content;
Weather weather = new Weather();
try {
content = weather.execute("https://api.openweathermap.org/data/2.5/weather?q=budapest,hu&units=metric&appid=ce2fd10cdcc8ab209f979f6a41c27cfe").get();
JSONObject jsonObject = new JSONObject(content);
String mainData = jsonObject.getString("main");
Log.i("mainData", mainData);//*
JSONObject object = new JSONObject(mainData);
Double temp = object.getDouble("temp");
Log.i("temp", String.valueOf(temp));
int temperBU = (int) Math.round(temp);
Log.i("temperBU", String.valueOf(temperBU));//*
layout = findViewById(R.id.hs_n);
if (temperBU == 19)
layout.setBackgroundResource(R.drawable.hungry_summer_premium_yes_simple);
else
layout.setBackgroundResource(R.drawable.hungry_summer_premium_no_simple);
} catch (Exception e) {
e.printStackTrace();
}
handler.postDelayed(this::run, 600000);
}
};
handler.postDelayed(r, 600000);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
}
Thank you so much for the help.

Answer 1

Please note that AsyncTask is deprecated, so use the following to do a background work:
Android AsyncTask API deprecating in Android 11.What are the alternatives?
In order to continue doing something after the user closed your app try using foreground service, like this:
in Android manifest, add
uses-permission android:name="android.permission.FOREGROUND_SERVICE"
this inside the application tag:
service android:name=".services.WorkerSvc"
add this class:
class WorkerSvc : Service() {
override fun onBind(intent: Intent?): IBinder? {
return null
}
override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
LogUtil.i("onStartCommand")
startForeground(
NotificationUtil.NOTIFICATION_ID,
NotificationUtil.makeForeGroundNotification(getString(R.string.please_wait))
)
processIntent(intent)
return START_STICKY
}
private fun processIntent(intent: Intent?) {
if (intent == null) {
stopSelf()
} else {
// DO YOUR WORK HERE. USE INTENT EXTRAS TO PASS DATA TO SERVICE
// NOTE THIS IS EXECUTED IN MAIN THREAD SO USE ONE OF THE SOLUTION PROVIDED IN A LINK ABOVE
}
}
}
To start the service:
val svcIntent = Intent(App.instance, WorkerSvc::class.java)
svcIntent.putExtra(
//DATA TO PASS TO SERVICE
)
if (context != null) {
ContextCompat.startForegroundService(context, svcIntent)
}