Insert JSON data into the SQLite database in android

Question

I want to insert the data from JSON array into the SQLite database. I have created two classes CategoryHelper.java and AndroidJSONParsingActivity.java to get the java response. When I run the code got the exception in databaseHelper.saveCategoryRecord(id,name); My API is working fine and giving me the data.

My code is below:

CategoryHelper.java

package com.androidhive.jsonparsing;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class CategoryHelper {
    private static final int DATABASE_VERSION = 2;
    private static final String DATABASE_NAME = "category.db";
    private static final String TABLE_NAME = "tbcategory";
    public static final String CATEGORY_COLUMN_ID = "_id";
    public static final String CATEGORY_COLUMN_NAME = "name";
    Category openHelper;
    private SQLiteDatabase database;

    public CategoryHelper(Context context){
        openHelper = new Category(context);
        database = openHelper.getWritableDatabase();
    }
    public void saveCategoryRecord(String id, String name) {
        ContentValues contentValues = new ContentValues();
        contentValues.put(CATEGORY_COLUMN_ID, id);
        contentValues.put(CATEGORY_COLUMN_NAME, name);
        database.insert(TABLE_NAME, null, contentValues);
        }
    public Cursor getTimeRecordList() {
        return database.rawQuery("select * from " + TABLE_NAME, null);
        }
    private class Category extends SQLiteOpenHelper {

        public Category(Context context) {
            // TODO Auto-generated constructor stub
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            // TODO Auto-generated method stub
            db.execSQL("CREATE TABLE " + TABLE_NAME + "( "
                    + CATEGORY_COLUMN_ID + " INTEGER PRIMARY KEY, "
                    + CATEGORY_COLUMN_NAME + " TEXT )" );

        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            // TODO Auto-generated method stub
            db.execSQL("DROP TABLE IF EXISTS"+ TABLE_NAME);
            onCreate(db);
        }

    }
}

AndroidJSONParsingActivity.java

package com.androidhive.jsonparsing;
import java.util.ArrayList;
import java.util.HashMap;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ListActivity;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;

public class AndroidJSONParsingActivity extends ListActivity {

    // url to make request
    private static String url="API TO GET THE DATA";
    // JSON Node names
    private static final String TAG_CATEGORY = "categories";
    private static final String TAG_CATEGORY_ID = "category_id";
    private static final String TAG_NAME = "name";
    private static final String TAG_IS_ACTIVE = "is_active";
    // contacts JSONArray
    JSONArray contacts = null;
    private CategoryHelper databaseHelper;
    //private SQLiteDatabase mydatabase = null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        // Hashmap for ListView
        ArrayList<HashMap<String, String>> contactList = new ArrayList<HashMap<String, String>>();

        // Creating JSON Parser instance
        JSONParser jParser = new JSONParser();

        // getting JSON string from URL
        JSONObject json = jParser.getJSONFromUrl(url);

        try {
            // Getting Array of Contacts
            contacts = json.getJSONArray(TAG_CATEGORY);

            // looping through All Contacts
            for(int i = 0; i < contacts.length(); i++){
                JSONObject c = contacts.getJSONObject(i);

                // Storing each json item in variable
                String id = c.getString(TAG_CATEGORY_ID);
                String name = c.getString(TAG_NAME);
                String  is_active = c.getString(TAG_IS_ACTIVE);

                databaseHelper.saveCategoryRecord(id,name);

                // creating new HashMap
                HashMap<String, String> map = new HashMap<String, String>();

                // adding each child node to HashMap key => value
                map.put(TAG_CATEGORY_ID, id);
                map.put(TAG_NAME, name);
                map.put(TAG_IS_ACTIVE, is_active);
                // adding HashList to ArrayList
                contactList.add(map);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }


        /**
         * Updating parsed JSON data into ListView
         * */
        ListAdapter adapter = new SimpleAdapter(this, contactList,
                R.layout.list_item,
                new String[] { TAG_NAME, TAG_IS_ACTIVE, TAG_CATEGORY_ID }, new int[] {
                        R.id.name, R.id.email, R.id.mobile });

        setListAdapter(adapter);

        // selecting single ListView item
        ListView lv = getListView();

        // Launching new screen on Selecting Single ListItem
        lv.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                // getting values from selected ListItem
                String name = ((TextView) view.findViewById(R.id.name)).getText().toString();
                String cost = ((TextView) view.findViewById(R.id.email)).getText().toString();
                String description = ((TextView) view.findViewById(R.id.mobile)).getText().toString();

                // Starting new intent
                Intent in = new Intent(getApplicationContext(), SingleMenuItemActivity.class);
                in.putExtra(TAG_NAME, name);
                in.putExtra(TAG_IS_ACTIVE, cost);
                in.putExtra(TAG_CATEGORY_ID, description);
                startActivity(in);

            }
        });



    }

}

LOGCAT:

01-21 20:13:49.226: E/AndroidRuntime(301): FATAL EXCEPTION: main
01-21 20:13:49.226: E/AndroidRuntime(301): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.androidhive.jsonparsing/com.androidhive.jsonparsing.AndroidJSONParsingActivity}: java.lang.NullPointerException
01-21 20:13:49.226: E/AndroidRuntime(301):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
01-21 20:13:49.226: E/AndroidRuntime(301):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
01-21 20:13:49.226: E/AndroidRuntime(301):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
01-21 20:13:49.226: E/AndroidRuntime(301):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
01-21 20:13:49.226: E/AndroidRuntime(301):  at android.os.Handler.dispatchMessage(Handler.java:99)
01-21 20:13:49.226: E/AndroidRuntime(301):  at android.os.Looper.loop(Looper.java:123)
01-21 20:13:49.226: E/AndroidRuntime(301):  at android.app.ActivityThread.main(ActivityThread.java:4627)
01-21 20:13:49.226: E/AndroidRuntime(301):  at java.lang.reflect.Method.invokeNative(Native Method)
01-21 20:13:49.226: E/AndroidRuntime(301):  at java.lang.reflect.Method.invoke(Method.java:521)
01-21 20:13:49.226: E/AndroidRuntime(301):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
01-21 20:13:49.226: E/AndroidRuntime(301):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
01-21 20:13:49.226: E/AndroidRuntime(301):  at dalvik.system.NativeStart.main(Native Method)
01-21 20:13:49.226: E/AndroidRuntime(301): Caused by: java.lang.NullPointerException
01-21 20:13:49.226: E/AndroidRuntime(301):  at com.androidhive.jsonparsing.AndroidJSONParsingActivity.onCreate(AndroidJSONParsingActivity.java:65)
01-21 20:13:49.226: E/AndroidRuntime(301):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
01-21 20:13:49.226: E/AndroidRuntime(301):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)

Please guide me how can I insert the JSON array data into the database or where I am doing wrong. Every response is appreciable.

Namaqualand

show me your android manifest file. – Matthei

@DawidSajdak this is my manifest pastebin.com/Tr2ukz45 – Namaqualand

It's getting a NullPointerException while parsing the JSON, so that means that there is a value missing or a null value somewhere in the JSON. I would log each value you are trying to read into logcat so you know more about what's happening, and maybe look at the JSON string you are trying to read from to compare. – Extemporaneous

Another small point to note about your DB helper is that you will need a space after the word "exists" in this line: db.execSQL("DROP TABLE IF EXISTS"+ TABLE_NAME); – Gethsemane

Answer 1

you forget to initialize databaseHelper object in oncreate of Activity before using it.

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        databaseHelper=new CategoryHelper(AndroidJSONParsingActivity.this);
        //your code here..........

Bluepoint

Answer 2

You never instantiate databaseHelper. You can't call a method on a null object.

Bandwidth

Answer 3

And you have one more little problem here:

db.execSQL("DROP TABLE IF EXISTS"+ TABLE_NAME);

You have forgotten space character after EXISTS. It should looks like this:

db.execSQL("DROP TABLE IF EXISTS "+ TABLE_NAME);

Generalist