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;
}
}
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.
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>
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