Add a reminder using local notifications

This article is based on multi-tasking environment in ios sdk. There is a simple solution put in place. This solution is known as push notifications. This solution is great and all, but it still requires to have an active internet connection. Furthermore, it is little bit difficult procedure. With iOS4, Apple has introduced a new type of notification that can be scheduled to fire within the device itself. That ‘s Local Notifications. Local notifications can be scheduled on the user’s iDevice to fire at any given time.

ReminderUI.h

#import <UIKit/UIKit.h>

@interface ReminderUI : UIViewController <UITableViewDataSource,UITableViewDelegate>
{
IBOutlet UITableView *tableview;
IBOutlet UIDatePicker *datePicker;
IBOutlet UITextField *eventText;
}
@property (nonatomic, retain) IBOutlet UITableView *tableview;
@property (nonatomic, retain) IBOutlet UIDatePicker *datePicker;
@property (nonatomic, retain) IBOutlet UITextField *eventText;

-(IBAction)scheduleAlarm:(id) sender;
-(IBAction)hideKeyBoard;
-(IBAction)goBack;

@end

ReminderUI.m

#import "ReminderUI.h"
#import "GreetingAppViewController.h"

@implementation ReminderUI
@synthesize datePicker,tableview, eventText;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {

}
return self;
}

- (void)dealloc
{
[super dealloc];
}

- (void) viewWillAppear:(BOOL)animated {
[self.tableview reloadData];
}

- (void)didReceiveMemoryWarning
{
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];

// Release any cached data, images, etc that aren't in use.
}

#pragma mark - View lifecycle

- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
}

- (void)viewDidUnload
{
[super viewDidUnload];
datePicker = nil;
tableview = nil;
eventText = nil;
}

-(IBAction)hideKeyBoard
{
[eventText resignFirstResponder];

}

-(BOOL)textFieldShouldReturn:(UITextField *)textField
{
[textField resignFirstResponder];
return  YES;
}

- (IBAction) scheduleAlarm:(id) sender
{
[eventText resignFirstResponder];

NSCalendar *calendar = [NSCalendar autoupdatingCurrentCalendar];

// Get the current date
NSDate *pickerDate = [self.datePicker date];

// Break the date up into components
NSDateComponents *dateComponents = [calendar components:( NSYearCalendarUnit | NSMonthCalendarUnit |  NSDayCalendarUnit )
fromDate:pickerDate];
NSDateComponents *timeComponents = [calendar components:( NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit )
fromDate:pickerDate];

// Set up the fire time
NSDateComponents *dateComps = [[NSDateComponents alloc] init];
[dateComps setDay:[dateComponents day]];
[dateComps setMonth:[dateComponents month]];
[dateComps setYear:[dateComponents year]];
[dateComps setHour:[timeComponents hour]];
// Notification will fire in one minute
[dateComps setMinute:[timeComponents minute]];
[dateComps setSecond:[timeComponents second]];
NSDate *itemDate = [calendar dateFromComponents:dateComps];
[dateComps release];

UILocalNotification *localNotif = [[UILocalNotification alloc] init];
if (localNotif == nil)
return;
localNotif.fireDate = itemDate;
localNotif.timeZone = [NSTimeZone defaultTimeZone];

// Notification details
localNotif.alertBody = [eventText text];
// Set the action button
localNotif.alertAction = @"View";

localNotif.soundName = UILocalNotificationDefaultSoundName;
localNotif.applicationIconBadgeNumber = 1;

// Specify custom data for the notification
NSDictionary *infoDict = [NSDictionary dictionaryWithObject:@"someValue" forKey:@"someKey"];
localNotif.userInfo = infoDict;

// Schedule the notification
[[UIApplication sharedApplication] scheduleLocalNotification:localNotif];
[localNotif release];

[self.tableview reloadData];
}

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{

return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{

return [[[UIApplication sharedApplication] scheduledLocalNotifications] count];

}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{

static NSString *CellIdentifier = @"Cell";

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
}

// Configure the cell...

NSArray *notificationArray = [[UIApplication sharedApplication] scheduledLocalNotifications];
UILocalNotification *notif = [notificationArray objectAtIndex:indexPath.row];

[cell.textLabel setText:notif.alertBody];
[cell.detailTextLabel setText:[notif.fireDate description]];

return cell;
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{

return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

-(IBAction)goBack
{
GreetingAppViewController *home= [[GreetingAppViewController alloc]initWithNibName:nil bundle:nil];
[self presentModalViewController:home animated:YES];
}

@end

Modify the appDelegate.m so that following changes will reflect.

appDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
// Override point for customization after application launch.

self.window.rootViewController = self.viewController;
[self.window makeKeyAndVisible];
application.applicationIconBadgeNumber = 0;

// Handle launching from a notification
UILocalNotification *localNotif =
[launchOptions objectForKey:UIApplicationLaunchOptionsLocalNotificationKey];
if (localNotif) {
NSLog(@"Recieved Notification %@",localNotif);
}

return YES;

}

- (void)application:(UIApplication *)app didReceiveLocalNotification:(UILocalNotification *)notif {
// Handle the notificaton when the app is running
NSLog(@"Recieved Notification %@",notif);
}