Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

Android Build a Weather App Hooking Up the Model to the View Weather Icon

Sarvesh Tandon
Sarvesh Tandon
1,142 Points

Why am I getting a null drawable? Weird error. Please Help!! :~(

05-27 23:40:57.218 9172-9210/com.sarveshtandon.www.stormy I/MainActivity: 11:11AM

05-27 23:40:57.225 9172-9172/com.sarveshtandon.www.stormy D/AndroidRuntime: Shutting down VM

05-27 23:40:57.226 9172-9172/com.sarveshtandon.www.stormy E/AndroidRuntime: FATAL EXCEPTION: main

    Process: com.sarveshtandon.www.stormy, PID: 9172

    java.lang.NullPointerException: Attempt to invoke virtual method 'void 

android.widget.ImageView.setImageDrawable(android.graphics.drawable.Drawable)' on a null object reference

        at com.sarveshtandon.www.stormy.MainActivity$1$1.run(MainActivity.java:83)

  at android.os.Handler.handleCallback(Handler.java:769)

        at android.os.Handler.dispatchMessage(Handler.java:98)

        at android.os.Looper.loop(Looper.java:164)

        at android.app.ActivityThread.main(ActivityThread.java:6540)

        at java.lang.reflect.Method.invoke(Native Method)

        at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)

        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

package com.sarveshtandon.www.stormy;

import android.app.Activity; import android.databinding.DataBindingUtil; import android.graphics.Bitmap; import android.graphics.drawable.Drawable; import android.nfc.Tag; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.text.method.LinkMovementMethod; import android.util.Log; import android.widget.ImageView; import android.widget.TextView;

import com.sarveshtandon.www.stormy.databinding.ActivityMainBinding;

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

import java.io.IOException;

import okhttp3.Call; import okhttp3.Callback; import okhttp3.OkHttpClient; import okhttp3.Request; import okhttp3.Response;

public class MainActivity extends AppCompatActivity {

private static final String TAG = MainActivity.class.getSimpleName();
private CurrentWeather currentWeather;
ImageView icon;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    final ActivityMainBinding binding =  DataBindingUtil.setContentView(MainActivity.this, R.layout.activity_main);
    TextView darkSkyView = findViewById(R.id.darkSkyView);
    darkSkyView.setMovementMethod(LinkMovementMethod.getInstance());

    String apiKey = "e9267719c11970d4e600f3cd50f7e94c";
    double latitude = 37.8267;
    double longtude = -122.4233;

    String forecastURL= "https://api.darksky.net/forecast/" + apiKey + "/" + latitude + "," + longtude;
    OkHttpClient client = new OkHttpClient();
    Request request = new Request.Builder().url(forecastURL).build();

    Call call = client.newCall(request);
    call.enqueue(new Callback() {
        @Override
        public void onFailure(Call call, IOException e) {

        }

        @Override
        public void onResponse(Call call, Response response) throws IOException {
            try {
                String JSONData = response.body().string();
                Log.v(TAG, JSONData);
                if(response.isSuccessful()){
                    currentWeather = getCurrentDetails(JSONData);

                    final CurrentWeather displayWeather = new CurrentWeather(
                            currentWeather.getLocationLabel(),
                            currentWeather.getIcon(),
                            currentWeather.getTime(),
                            currentWeather.getTemperature(),
                            currentWeather.getHumidity(),
                            currentWeather.getPrecipChance(),
                            currentWeather.getSummary()
                    );
                    Log.i(TAG,displayWeather.getFormattedTime("America/Los_Angeles"));
                    Log.i(TAG,String.valueOf(displayWeather.getIcon())+"hey");
                    Log.i(TAG, String.valueOf(R.drawable.clear_day));
                    Drawable drawable = getResources().getDrawable(currentWeather.getIconId());
                    Log.i(TAG,displayWeather.getFormattedTime("America/Los_Angeles"));
                    binding.setWeather(displayWeather);
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Drawable drawable = getResources().getDrawable(currentWeather.getIconId());
                            icon.setImageDrawable(drawable);
                        }
                    });

                }
                else{
                    alertUserAboutTheError();
                }
            } catch (IOException e) {
                Log.e(TAG, "IOException Caught:" ,e);
            } catch (JSONException e){
                Log.e(TAG, "JSONException caught:",e);
            }
        }
    });

}

private CurrentWeather getCurrentDetails(String data) throws JSONException {
    JSONObject forecast = new JSONObject(data);
    String timezone = forecast.getString("timezone");
    Log.i(TAG, "From JSON:"+timezone);

    JSONObject currently = forecast.getJSONObject("currently");
    CurrentWeather currentWeather = new CurrentWeather();
    currentWeather.setTemperature(currently.getDouble("temperature"));
    currentWeather.setTime(currently.getLong("time"));
    currentWeather.setHumidity(currently.getDouble("humidity"));
    currentWeather.setLocationLabel("Alcataraz Island, CA");
    currentWeather.setIcon(currently.getString("icon"));
    currentWeather.setPrecipChance(currently.getDouble("precipProbability"));
    currentWeather.setSummary(currently.getString("summary"));
    Log.i(TAG, currentWeather.getFormattedTime(timezone));
    return currentWeather;

}

private void alertUserAboutTheError() {
    AlertDialogFragment dialog = new AlertDialogFragment();
    dialog.show(getFragmentManager(), "error_dialog");


}

}

Sarvesh Tandon
Sarvesh Tandon
1,142 Points

Check this out! even when I am inputing an ID which exists it is giving me the following error. PS I have already tried putting a try catch for a NULLexception

 runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                Drawable drawable = getResources().getDrawable(currentWeather.getIconId());

                                icon.setImageResource(R.drawable.clear_day);

                            }
                        });
05-28 00:22:49.627 12371-12371/com.sarveshtandon.www.stormy D/AndroidRuntime: Shutting down VM
05-28 00:22:49.627 12371-12371/com.sarveshtandon.www.stormy E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.sarveshtandon.www.stormy, PID: 12371
    java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ImageView.setImageResource(int)' on a null object reference
        at com.sarveshtandon.www.stormy.MainActivity$1$1.run(MainActivity.java:84)
        at android.os.Handler.handleCallback(Handler.java:769)
        at android.os.Handler.dispatchMessage(Handler.java:98)
        at android.os.Looper.loop(Looper.java:164)
        at android.app.ActivityThread.main(ActivityThread.java:6540)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

1 Answer

Seth Kroger
Seth Kroger
56,402 Points

It looks like you declared the icon variable, but you forgot to initialize it through findViewById() in onCreate().