java.lang.NullPointerException BaseAdapter

Question

package com.oikostuio.newsapp.ui;
import android.app.ListActivity;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
import com.oikostuio.newsapp.R;
import com.oikostuio.newsapp.adapter.NewsAdapter;
import com.oikostuio.newsapp.news.CurrentStatus;
import com.oikostuio.newsapp.news.Doc;
import com.oikostuio.newsapp.news.News;
import com.squareup.okhttp.Call;
import com.squareup.okhttp.Callback;
import com.squareup.okhttp.OkHttpClient;
import com.squareup.okhttp.Request;
import com.squareup.okhttp.Response;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.IOException;
import butterknife.ButterKnife;
import butterknife.InjectView;
public class MainActivity extends ListActivity {
public static final String TAG = MainActivity.class.getSimpleName();

private News mNews;
public Doc[] mDocsToAdapter;

private ListView newsListView;
@InjectView(R.id.statusValue) TextView mStatusValue;
@InjectView(R.id.refreshImageView) ImageView mRefreshImageView;
@InjectView(R.id.progressBar) ProgressBar mProgressBar;

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

mProgressBar.setVisibility(View.INVISIBLE);

mRefreshImageView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            getNews();
        }
    });
    getNews();
    Log.d(TAG, "Main UI code is running!");

newsListView = (ListView) findViewById(android.R.id.list);
    displayNews();

}

public void displayNews() {
    getIntent();
    NewsAdapter adapter = new NewsAdapter(this, mDocsToAdapter);
    newsListView.setAdapter(adapter);
}

private void getNews() {

String newsUrl = "http://api.nytimes.com/svc/search/v2/articlesearch.json?api-key=sample-key";

if (isNetworkAvailable()) {
        toggleRefresh();

OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder()
                .url(newsUrl)
                .build();

Call call = client.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Request request, IOException e) {
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        toggleRefresh();
                    }
                });
                alertUserAboutError();
            }

@Override
            public void onResponse(Response response) throws IOException {
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        toggleRefresh();
                    }
                });

try {
                    String jsonData = response.body().string();
                    Log.v(TAG, jsonData);
                    if (response.isSuccessful()) {
                        mNews = parseForcecastDetails(jsonData);
                        runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                updateDisplay();
                            }
                        });
                    } else {
                        alertUserAboutError();
                    }
                }
                catch (IOException e) {
                    Log.e(TAG, "Exception caught: ", e);
                }
                catch (JSONException e) {
                    Log.e(TAG, "Exception caught: ", e);
                }
            }
        });
    }
    else {
        Toast.makeText(this, getString(R.string.network_unavailable_message),
                Toast.LENGTH_LONG).show();
    }
}

private void toggleRefresh() {
    if (mProgressBar.getVisibility() == View.INVISIBLE) {
        mProgressBar.setVisibility(View.VISIBLE);
        mRefreshImageView.setVisibility(View.INVISIBLE);
    }
    else {
        mProgressBar.setVisibility(View.INVISIBLE);
        mRefreshImageView.setVisibility(View.VISIBLE);
    }
}

private void updateDisplay() {
    CurrentStatus currentStatus = mNews.getCurrentStatus();
    mStatusValue.setText(currentStatus.getKEY_STATUS());
}

private News parseForcecastDetails(String jsonData) throws JSONException {
    News news = new News();
    news.setCurrentStatus(getCurrentDetails(jsonData));
    news.setDailyNews(getDailyNews(jsonData));

return news;
}

private Doc[] getDailyNews(String jsonData) throws JSONException {
    JSONObject news = new JSONObject(jsonData);
    String status = news.getString("status");
    JSONObject response = news.getJSONObject("response");
    JSONArray docsInJSON = response.getJSONArray("docs");

Doc[] docs = new Doc[docsInJSON.length()];
    for(int i = 0; i < docsInJSON.length(); i++) {
        JSONObject jsonResult = docsInJSON.getJSONObject(i);
        JSONObject headline = jsonResult.getJSONObject("headline");
        String main = headline.getString("main");

Doc docFromNews = new Doc();

docFromNews.setWebUrl(jsonResult.getString("web_url"));
        docFromNews.setSnippet(jsonResult.getString("snippet"));
        docFromNews.setPubDate(jsonResult.getString("pub_date"));
        docFromNews.setSection(jsonResult.getString("section_name"));
        docFromNews.setSource(jsonResult.getString("source"));
        docFromNews.setKEY_STATUS(status);
        docFromNews.setHeadline(main);

docs[i] = docFromNews;

}

return docs;
}

private CurrentStatus getCurrentDetails(String jsonData) throws JSONException {
    JSONObject forecast = new JSONObject(jsonData);

String status = forecast.getString("status");
    Log.i(TAG, "From JSON: " + status);

CurrentStatus currentStatus = new CurrentStatus();
    currentStatus.setKEY_STATUS(status);

return currentStatus;
}

private boolean isNetworkAvailable() {
    ConnectivityManager manager = (ConnectivityManager)
            getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = manager.getActiveNetworkInfo();
    boolean isAvailable = false;
    if (networkInfo != null && networkInfo.isConnected()) {
        isAvailable = true;
    }

return isAvailable;
}

private void alertUserAboutError() {
    AlertDialogFragment dialog = new AlertDialogFragment();
    dialog.show(getFragmentManager(), "error_dialog");
}
}
package com.oikostuio.newsapp.adapter;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import com.oikostuio.newsapp.R;
import com.oikostuio.newsapp.news.Doc;
/**
 * Created by jeonhonlee on 5/22/15.
 */
public class NewsAdapter extends BaseAdapter {
private Context mContext;
private Doc[] mDocs;

public NewsAdapter(Context context, Doc[] docs) {
    mContext = context;
    mDocs = docs;
}

@Override
public int getCount() {
    return mDocs.length;
}

@Override
public Object getItem(int position) {
    return mDocs[position];
}

@Override
public long getItemId(int position) {
    return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    final ViewHolder holder;

if(convertView == null) {
        // brand now
        convertView = LayoutInflater.from(mContext).inflate(R.layout.news_list_item, null);
        holder = new ViewHolder();

holder.sectionLabel = (TextView) convertView.findViewById(R.id.sectionLabel);
        holder.mainLabel = (TextView) convertView.findViewById(R.id.mainLabel);
        holder.sourceLabel = (TextView) convertView.findViewById(R.id.sourceLabel);
        holder.pubDateLabel = (TextView) convertView.findViewById(R.id.pubDateLabel);

convertView.setTag(holder);
    } else {
        holder = (ViewHolder) convertView.getTag();
    }

Doc doc = mDocs[position];

holder.mainLabel.setText(doc.getHeadline());
    holder.pubDateLabel.setText(doc.getPubDate());
    holder.sectionLabel.setText(doc.getSection());
    holder.sourceLabel.setText(doc.getSource());

return convertView;
}

private static class ViewHolder {

TextView sectionLabel;
    TextView mainLabel;
    TextView sourceLabel;
    TextView pubDateLabel;

}
}
package com.oikostuio.newsapp.news;
/**
 * Created by jeonhonlee on 5/22/15.
 */
public class News {
private CurrentStatus mCurrentStatus;
private Doc[] mDailyNews;

public Doc[] getDailyNews() {
    return mDailyNews;
}

public void setDailyNews(Doc[] dailyNews) {
    mDailyNews = dailyNews;
}

public CurrentStatus getCurrentStatus() {
    return mCurrentStatus;
}

public void setCurrentStatus(CurrentStatus currentStatus) {
    mCurrentStatus = currentStatus;
}
}
private String KEY_STATUS;

public String getKEY_STATUS() {
    return KEY_STATUS;
}

public void setKEY_STATUS(String KEY_STATUS) {
    this.KEY_STATUS = KEY_STATUS;
}
package com.oikostuio.newsapp.news;
/**
 * Created by jeonhonlee on 5/21/15.
 */
public class Doc {
private String mWebUrl; // web_url
private String mSnippet; // snippet
private String mPubDate; // pub_date
private String mSource; // source
private String mSection; // section_name
private String KEY_STATUS; // status
private String mHeadline; // Headline

public String getHeadline() {
    return mHeadline;
}

public void setHeadline(String headline) {
    mHeadline = headline;
}

public String getKEY_STATUS() {
    return KEY_STATUS;
}

public void setKEY_STATUS(String KEY_STATUS) {
    this.KEY_STATUS = KEY_STATUS;
}

public String getWebUrl() {
    return mWebUrl;
}

public void setWebUrl(String webUrl) {
    mWebUrl = webUrl;
}

public String getSnippet() {
    return mSnippet;
}

public void setSnippet(String snippet) {
    mSnippet = snippet;
}

public String getPubDate() {
    return mPubDate;
}

public void setPubDate(String pubDate) {
    mPubDate = pubDate;
}

public String getSource() {
    return mSource;
}

public void setSource(String source) {
    mSource = source;
}

public String getSection() {
    return mSection;
}

public void setSection(String section) {
    mSection = section;
}
}
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.oikostuio.newsapp/com.oikostuio.newsapp.ui.MainActivity}: java.lang.NullPointerException
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
        at android.app.ActivityThread.access$600(ActivityThread.java:130)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:137)
        at android.app.ActivityThread.main(ActivityThread.java:4745)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:511)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
        at dalvik.system.NativeStart.main(Native Method)
 Caused by: java.lang.NullPointerException
        at com.oikostuio.newsapp.adapter.NewsAdapter.getCount(NewsAdapter.java:28)
        at android.widget.ListView.setAdapter(ListView.java:460)
        at com.oikostuio.newsapp.ui.MainActivity.displayNews(MainActivity.java:76)
        at com.oikostuio.newsapp.ui.MainActivity.onCreate(MainActivity.java:69)
        at android.app.Activity.performCreate(Activity.java:5008)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
            at android.app.ActivityThread.access$600(ActivityThread.java:130)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:4745)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
            at dalvik.system.NativeStart.main(Native Method)

JIHOON JUNG · Answer

Please help me, I'm stuck in this code for 2 days

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java.lang.NullPointerException BaseAdapter

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at com.oikostuio.newsapp.adapter.NewsAdapter.getCount(NewsAdapter.java:28)

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