MainActivity.java

package com.example.ramesh.camera;

import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;

public class MainActivity extends AppCompatActivity {

    private EditText cityInput;
    private Button fetchWeatherButton;
    private ProgressBar loadingIndicator;
    private TextView weatherResult;

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

        cityInput = (EditText) findViewById(R.id.cityInput);
        fetchWeatherButton = (Button) findViewById(R.id.fetchWeatherButton);
        loadingIndicator = (ProgressBar) findViewById(R.id.loadingIndicator);
        weatherResult = (TextView) findViewById(R.id.weatherResult);

        fetchWeatherButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String cityName = cityInput.getText().toString().trim();
                if (TextUtils.isEmpty(cityName)) {
                    Toast.makeText(MainActivity.this, "Please enter a city name", Toast.LENGTH_SHORT).show();
                    return;
                }

                new WeatherTask().execute(cityName);
            }
        });
    }

    private class WeatherTask extends AsyncTask<String, Void, String> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            loadingIndicator.setVisibility(View.VISIBLE);
            fetchWeatherButton.setEnabled(false);
            weatherResult.setText("");
        }

        @Override
        protected String doInBackground(String... params) {
            String cityName = params[0];
            try {
                return fetchWeather(cityName);
            } catch (IOException e) {
                return "Network error: " + e.getMessage();
            } catch (JSONException e) {
                return "Unable to read weather data right now.";
            }
        }

        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);
            loadingIndicator.setVisibility(View.GONE);
            fetchWeatherButton.setEnabled(true);
            weatherResult.setText(result);
        }
    }

    private String fetchWeather(String cityName) throws IOException, JSONException {
        String encodedCity = URLEncoder.encode(cityName, "UTF-8");
        String geocodeUrl = "https://geocoding-api.open-meteo.com/v1/search?name=" + encodedCity + "&count=1&language=en";

        JSONObject geocodeResponse = new JSONObject(readFromUrl(geocodeUrl));
        JSONArray results = geocodeResponse.optJSONArray("results");

        if (results == null || results.length() == 0) {
            return "No results found for \"" + cityName + "\".";
        }

        JSONObject location = results.getJSONObject(0);
        double latitude = location.getDouble("latitude");
        double longitude = location.getDouble("longitude");
        String resolvedName = location.optString("name");
        String country = location.optString("country");

        String weatherUrl = "https://api.open-meteo.com/v1/forecast?current_weather=true&latitude="
                + latitude + "&longitude=" + longitude + "&timezone=auto";

        JSONObject weatherResponse = new JSONObject(readFromUrl(weatherUrl));
        JSONObject currentWeather = weatherResponse.optJSONObject("current_weather");

        if (currentWeather == null) {
            return "Weather details are unavailable right now.";
        }

        double temperature = currentWeather.optDouble("temperature");
        double windSpeed = currentWeather.optDouble("windspeed");
        String time = currentWeather.optString("time");

        StringBuilder builder = new StringBuilder();
        builder.append("Current weather in ").append(resolvedName);
        if (!TextUtils.isEmpty(country)) {
            builder.append(", ").append(country);
        }
        builder.append(":\n\n");
        builder.append("Temperature: ").append(temperature).append("°C\n");
        builder.append("Wind speed: ").append(windSpeed).append(" km/h\n");
        if (!TextUtils.isEmpty(time)) {
            builder.append("Updated at: ").append(time);
        }

        return builder.toString();
    }

    private String readFromUrl(String urlString) throws IOException {
        HttpURLConnection connection = null;
        BufferedReader reader = null;
        try {
            URL url = new URL(urlString);
            connection = (HttpURLConnection) url.openConnection();
            connection.setConnectTimeout(10000);
            connection.setReadTimeout(10000);

            InputStream inputStream = connection.getInputStream();
            reader = new BufferedReader(new InputStreamReader(inputStream));
            StringBuilder builder = new StringBuilder();
            String line;
            while ((line = reader.readLine()) != null) {
                builder.append(line);
            }
            return builder.toString();
        } finally {
            if (reader != null) {
                reader.close();
            }
            if (connection != null) {
                connection.disconnect();
            }
        }
    }
}