SQLite Database issue in TextView

Question

I've been working on an app where the main Activity leads to CalendarActivity, which has a button leading to another Activity where the user creates an event. Once the event is created, the user is taken back to CalendarActivity, and a previously empty TextView displays the event. The code I've used seems like it should work, and is near verbatim from an online tutorial. I researched the comments of the video and the video maker's blog, and many others seem to say it works fine. I've check over and over, and I believe that its grammatically correct, etc, but I can not get it to load the event into the TextView. Any pointers even would help. I would ask you keep it near basic english, I am just getting into programming and am using this app as a learning experience.

Thanks!

CalendarActivity:

package com.bm.sn.sbeta;

import android.content.Intent;
import android.database.Cursor;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CalendarView;
import android.widget.TextView;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;

public class CalendarActivity extends AppCompatActivity {

CalendarView calendar;
Button createEvent;
public static String createEventDate;
DatabaseHelper db;

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

    Cursor result = db.getAllData();
    if (result.getCount() == 0) {

        noEventToday();

    }else{

        TextView eventList = (TextView)findViewById(R.id.eventList);
        StringBuffer stringBuffer = new StringBuffer();

        while (result.moveToNext()) {

            stringBuffer.append("eventDat : "+result.getString(0)+"\n");
            stringBuffer.append("timeHour : "+result.getString(1)+"\n");
            stringBuffer.append("timeMinue : "+result.getString(2)+"\n");
            stringBuffer.append("event : "+result.getString(3)+"\n");
            stringBuffer.append("location : "+result.getString(4)+"\n");
            stringBuffer.append("crew : "+result.getString(5)+"\n\n");
            eventList.setText(stringBuffer);


        }
    }

    calendar = (CalendarView)findViewById(R.id.calendar);
    calendar.setOnDateChangeListener(new CalendarView.OnDateChangeListener(){
        @Override
        public void onSelectedDayChange(CalendarView view, int year, int month, int dayOfMonth){
            createEventDate = (month+"."+dayOfMonth+"."+year);
            createEvent.setText("Create Event for "+createEventDate);
            }
    });

    createEvent = (Button)findViewById(R.id.eventCreateButton);
    createEvent.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent toEventCreateActivity = new Intent(CalendarActivity.this, EventCreateActivity.class);
            startActivity(toEventCreateActivity);
        }
    });
}

/*public void fillEventList (){

}

public void noEventToday(){
    TextView eventList = (TextView)findViewById(R.id.eventList);
    eventList.setText("Nothing scheduled for today.");
}*/
}

EventCreateActivity:

package com.bm.sn.sbeta;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.TimePicker;
import android.widget.Toast;

public class EventCreateActivity extends AppCompatActivity {

DatabaseHelper db;

String textViewText = CalendarActivity.createEventDate;

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

    db = new DatabaseHelper(this);

    final TextView titleTextView = (TextView)findViewById(R.id.titleTextView);
    titleTextView.setText("Create event for "+textViewText);

    final TimePicker timePicker = (TimePicker)findViewById(R.id.timePicker);

    final EditText entryEvent = (EditText)findViewById(R.id.entryEvent);
    final EditText entryLocation = (EditText)findViewById(R.id.entryLocation);
    final EditText entryCrew = (EditText)findViewById(R.id.entryCrew);

    Button createEventButton = (Button)findViewById(R.id.saveEvent);
    createEventButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            db.insertData(
                    titleTextView.toString(),
                    timePicker.getCurrentHour().toString(),
                    timePicker.getCurrentMinute().toString(),
                    entryEvent.getText().toString(),
                    entryLocation.getText().toString(),
                    entryCrew.getText().toString()
                    );

            Toast.makeText(EventCreateActivity.this, "I'll keep that in mind.", Toast.LENGTH_LONG).show();
            Intent toCalendarActivity = new Intent(EventCreateActivity.this, CalendarActivity.class);
            startActivity(toCalendarActivity);


        }
    });
}
}

DatabaseHelper:

package com.bm.sn.sbeta;

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

public class DatabaseHelper extends SQLiteOpenHelper{

public static final String DATABASE_NAME = "SavitaCalendar.db";
public static final String TABLE_NAME = "CalendarEvents";
public static final String col_0 = "ID";
public static final String col_1 = "eventDate" ;
public static final String col_2 = "timeHour";
public static final String col_3 = "timeMinute";
public static final String col_4 = "event";
public static final String col_5 = "location";
public static final String col_6 = "crew";


public DatabaseHelper(Context context) {
    super(context, DATABASE_NAME, null, 1);
}

@Override
public void onCreate(SQLiteDatabase db) {

    db.execSQL("create table "+TABLE_NAME+ " (ID INTEGER PRIMARY KEY AUTOINCREMENT,EVENTDATE TEXT,TIMEHOUR TEXT,TIMEMINUTE TEXT, EVENT TEXT, LOCATION TEXT, CREW TEXT); ");

}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

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

}



public void insertData (String eventDate, String timeHour, String timeMinute, String event, String location, String crew){

    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues contentValues = new ContentValues();
    contentValues.put(col_1, eventDate);
    contentValues.put(col_2, timeHour);
    contentValues.put(col_3, timeMinute);
    contentValues.put(col_4, event);
    contentValues.put(col_5, location);
    contentValues.put(col_6, crew);

    db.insert(TABLE_NAME, null, contentValues);
    db.close();

}

public Cursor getAllData(){

    SQLiteDatabase db = this.getWritableDatabase();
    Cursor result = db.rawQuery("select * from "+TABLE_NAME, null);
    return result;

}
}

earthw0rmjim · Accepted Answer · 2016-07-17T07:00:32.663

You're reading your data from the DB in onCreate().

onCreate() is called when the Activity is (re)created. It is not guaranteed that it will be called when you navigate back from EventCreateActivity.

Take a look at the docs on the Activity lifecycle.

As @nuccio pointed it out, you also seem to forgot to initialize your DatabaseHelper instance.

You should use a singleton pattern there, something like this:

private static DatabaseHelper instance;

private DatabaseHelper(Context context) {
    super(context, DATABASE_NAME, null, 1);
}

public static DatabaseHelper getInstance(Context context) {
    if (instance == null) {
        instance = new DatabaseHelper(context.getApplicationContext());
    }
    return instance;
}

You could start EventCreateActivity using startActivityForResult(), and override onActivityResult() in CalendarActivity to update your TextView.

For example:

public class CalendarActivity extends AppCompatActivity {

    private static final int REQUEST_CREATE_EVENT = 0;

    CalendarView calendar;
    Button createEvent;
    public static String createEventDate;
    TextView eventList;

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

        eventList = (TextView) findViewById(R.id.eventList);

        getEvents();

        calendar = (CalendarView) findViewById(R.id.calendar);
        calendar.setOnDateChangeListener(new CalendarView.OnDateChangeListener() {
            @Override
            public void onSelectedDayChange(CalendarView view, int year, int month, int dayOfMonth) {
                createEventDate = (month + "." + dayOfMonth + "." + year);
                createEvent.setText("Create Event for " + createEventDate);
            }
        });

        createEvent = (Button) findViewById(R.id.eventCreateButton);
        createEvent.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent toEventCreateActivity = new Intent(CalendarActivity.this, EventCreateActivity.class);
                startActivityForResult(toEventCreateActivity, REQUEST_CREATE_EVENT);
            }
        });
    }

    private void getEvents() {
        // getting our DatabaseHelper instance
        DatabaseHelper db = DatabaseHelper.getInstance(this);

        Cursor result = db.getAllData();
        if (result.getCount() == 0) {
            noEventToday();
        } else {
            StringBuffer stringBuffer = new StringBuffer();
            while (result.moveToNext()) {
                stringBuffer.append("eventDat : " + result.getString(0) + "\n");
                stringBuffer.append("timeHour : " + result.getString(1) + "\n");
                stringBuffer.append("timeMinue : " + result.getString(2) + "\n");
                stringBuffer.append("event : " + result.getString(3) + "\n");
                stringBuffer.append("location : " + result.getString(4) + "\n");
                stringBuffer.append("crew : " + result.getString(5) + "\n\n");
                eventList.setText(stringBuffer);
            }
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if(resultCode == RESULT_OK && requestCode == REQUEST_CREATE_EVENT) {
            getEvents();
        }
    }

    public void noEventToday(){
        TextView eventList = (TextView)findViewById(R.id.eventList);
        eventList.setText("Nothing scheduled for today.");
    }
}

And in EventCreateActivity:

createEventButton.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        db.insertData(
            titleTextView.toString(),
            timePicker.getCurrentHour().toString(),
            timePicker.getCurrentMinute().toString(),
            entryEvent.getText().toString(),
            entryLocation.getText().toString(),
            entryCrew.getText().toString()
        );

        Toast.makeText(EventCreateActivity.this, "I'll keep that in mind.", Toast.LENGTH_LONG).show();

        setResult(RESULT_OK);
        finish();
    }
});

An even better approach would be to pass your new event data in the Intent, so you don't have to read the DB when going back to CalendarActivity.

Or at least return the new row ID, so only one record needs to be queried.

nuccio · Answer 2 · 2016-07-17T16:08:49.210

You didn't instantiate your db properly in CalendarActivity.

add this

db = new DatabaseHelper(this);

Here is where to add this to the class:

 package com.mac.training.calendaractivitysqlhelperthing;

 imports ...

 public class CalendarActivity extends AppCompatActivity {

 CalendarView calendar;
 Button createEvent;
 public static String createEventDate;
 DatabaseHelper db;

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

    //ADD this line here
    db = new DatabaseHelper(this);

    Cursor result = db.getAllData();
    if (result.getCount() == 0) {

       //noEventToday();

    }else{

        //etc

That alone should work, but if not. Also update your Manifest as well with this:

activity android:name=".EventCreateActivity"

  <?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.mac.training.calendaractivitysqlhelperthing">


  <application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".CalendarActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
       </activity>

         <activity android:name=".EventCreateActivity" />
     </application>

</manifest>

public DatabaseHelper(Context context) { super(context, DATABASE_NAME, null, 1); } — nuccio, Jul 17 '16 at 15:42
Okay... That's a database code... Doesn't have anything to do with the XML attribute — OneCricketeer, Jul 17 '16 at 15:43
In order to get an instance of db helper class. You need to pass the context as a parameter. That's necessary to create an instance. — nuccio, Jul 17 '16 at 15:49
I know that. That still is not related to the line of XML I referrred to — OneCricketeer, Jul 17 '16 at 15:53
Oh your right, I removed that line from the XML and it worked the same. I will remove that part from my answer. Thank you for making my answer better cricket_007. — nuccio, Jul 17 '16 at 16:07

SQLite Database issue in TextView

2 Answers2