Proof of android development

MainActivity.java

package com.example.weatherapp;

import androidx.appcompat.app.AppCompatActivity;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;

import com.google.gson.Gson;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void onGetTemp(View v) {
        EditText editText = findViewById(R.id.editText);
        String city = editText.getText().toString();

        Runnable r = new WeatherTask(this, city);
        Thread t = new Thread(r);
        t.start();
    }

    public void onGetForecast(View v) {
        EditText editText = findViewById(R.id.editText);
        String city = editText.getText().toString();

        Runnable r = new ForecastTask(this, city);
        Thread t = new Thread(r);
        t.start();
    }
}

class WeatherTask implements Runnable {
    private String city;
    private Activity parentActivity;

    WeatherTask(Activity parent, String city) {
        this.city = city;
        parentActivity = parent;
    }

    @Override
    public void run() {
        Log.d("WeatherTask", "Getting weather for " + city);

        String url = "";

        try {
            url = "https://api.openweathermap.org/data/2.5/weather?q=" + URLEncoder.encode(city, "UTF-8") + "&apiKey=830472d14b275cc781bbd5a0fe04e376";
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

        WeatherConditions weatherConditions = null;

        try {
            InputStream response = new URL(url).openStream();
            Reader reader = new InputStreamReader(response);

            weatherConditions = new Gson().fromJson(reader, WeatherConditions.class);
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        Log.d("WeatherTask", "Current temp in " + city + ": " + weatherConditions.measurements.temp);

        WeatherConditions finalWeatherConditions = weatherConditions;
        parentActivity.runOnUiThread(() -> {
            Toast t = Toast.makeText(parentActivity, "Temperature in " + city + " is " + finalWeatherConditions.measurements.temp + "k", Toast.LENGTH_LONG);
            t.show();
        });
    }
}

class ForecastTask implements Runnable {
    private String city;
    private Activity parentActivity;

    public ForecastTask(Activity parent, String city) {
        this.city = city;
        parentActivity = parent;
    }

    @Override
    public void run() {
        Log.d("ForecastTask", "Getting forecast for " + city);

        String url = "";

        try {
            url = "https://api.openweathermap.org/data/2.5/forecast?q=" + URLEncoder.encode(city, "UTF-8") + "&apiKey=830472d14b275cc781bbd5a0fe04e376";
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

        WeatherForecast weatherForecast = null;

        try {
            InputStream response = new URL(url).openStream();
            Reader reader = new InputStreamReader(response);

            weatherForecast = new Gson().fromJson(reader, WeatherForecast.class);
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        WeatherForecast finalWeatherForecast = weatherForecast;
        parentActivity.runOnUiThread(() -> {
            ListView listView = parentActivity.findViewById(R.id.listView);
            assert finalWeatherForecast != null;

            ArrayAdapter<WeatherForecastItem> arrayAdapter = new ArrayAdapter<>(parentActivity, android.R.layout.simple_list_item_1, finalWeatherForecast.list);

            listView.setAdapter(arrayAdapter);
        });
    }
}