This is an app I am learning to code on, it uses an API to get the weather in certain cities. For some reason the app just dies and I am not able to find out why. The code and the error is as below.
Can anyone help and also if so how did you find the exact error I know the code has said 2 lines where there is errors but this code worked for others using the same lectures as me
the error:
5-22 13:10:15.035 10511-10511/com.example.david.whatstheweather E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.david.whatstheweather, PID: 10511
java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.length()' on a null object reference
at org.json.JSONTokener.nextCleanInternal(JSONTokener.java:116)
at org.json.JSONTokener.nextValue(JSONTokener.java:94)
at org.json.JSONObject.<init>(JSONObject.java:156)
at org.json.JSONObject.<init>(JSONObject.java:173)
at com.example.david.whatstheweather.MainActivity$DownloadTask.onPostExecute(MainActivity.java:135)
at com.example.david.whatstheweather.MainActivity$DownloadTask.onPostExecute(MainActivity.java:78)
at android.os.AsyncTask.finish(AsyncTask.java:636)
at android.os.AsyncTask.access$500(AsyncTask.java:177)
at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:653)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
the code:
import android.app.Activity;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;
public class MainActivity extends Activity {
EditText cityName;
TextView resultTextView;
public void findWeather(View view) {
Log.i("cityName", cityName.getText().toString());
InputMethodManager mgr = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
mgr.hideSoftInputFromWindow(cityName.getWindowToken(), 0);
try {
String encodedCityName = URLEncoder.encode(cityName.getText().toString(), "UTF-8");
DownloadTask task = new DownloadTask();
task.execute("http://api.openweathermap.org/data/2.5/weather?q=" + encodedCityName + "appid=5cf109a38ccf8138486a2e238847cc0d")
;
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(), "Could not find weather", Toast.LENGTH_LONG).show();
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
cityName = (EditText) findViewById(R.id.cityName);
resultTextView = (TextView) findViewById(R.id.resultTextView);
}
public class DownloadTask extends AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... urls) {
String result = "";
URL url;
HttpURLConnection urlConnection = null;
try {
url = new URL(urls[0]);
urlConnection = (HttpURLConnection) url.openConnection();
InputStream in = urlConnection.getInputStream();
InputStreamReader reader = new InputStreamReader(in);
int data = reader.read();
while (data != -1) {
char current = (char) data;
result += current;
data = reader.read();
}
return result;
} catch (Exception e) {
Handler h = new Handler(Looper.getMainLooper());
h.post(new Runnable() {
public void run() {
Toast.makeText(getApplicationContext(), "Could not find weather", Toast.LENGTH_LONG).show();
}
});
//Toast.makeText(getApplicationContext(), "Could not find weather", Toast.LENGTH_LONG).show();
}
return null;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
try {
String message = "";
JSONObject jsonObject = new JSONObject(result);
String weatherInfo = jsonObject.getString("weather");
Log.i("Weather content", weatherInfo);
JSONArray arr = new JSONArray(weatherInfo);
for (int i = 0; i < arr.length(); i++) {
JSONObject jsonPart = arr.getJSONObject(i);
String main = "";
String description = "";
main = jsonPart.getString("main");
description = jsonPart.getString("description");
if (main != "" && description != "") {
message += main + ": " + description + "\r\n";
}
}
if (message != "") {
resultTextView.setText(message);
} else {
Toast.makeText(getApplicationContext(), "Could not find weather", Toast.LENGTH_LONG).show();
}
} catch (JSONException e) {
Toast.makeText(getApplicationContext(), "Could not find weather", Toast.LENGTH_LONG).show();
}
}
}
}
