iphone - UIDatePicker 调度程序错误

Question

我已按照本教程 http://ios.biomsoft.com/2011/08/27/iphone-programming-tutorial- --local-notifications/ 我能够运行该应用程序，但是为了运行我拥有的应用程序在我的 appdelegate.m 中删除以下代码

您可以在上图中看到错误。

为什么我会收到错误以及如何修复错误？

这是我的代码。

。H

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController <UITableViewDelegate,UITableViewDataSource> {
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;

@end

.m

@implementation ViewController

@synthesize datePicker,tableview, eventText;

- (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];

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];

[self.tableview reloadData];

}

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

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

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

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
// We only have one section
return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
// Return the number of notifications
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];
}

// Get list of local notifications
NSArray *notificationArray = [[UIApplication sharedApplication]    
scheduledLocalNotifications];
UILocalNotification *notif = [notificationArray objectAtIndex:indexPath.row];

// Display notification info
[cell.textLabel setText:notif.alertBody];
[cell.detailTextLabel setText:[notif.fireDate description]];

return cell;
}
@end

Answer 1

您必须创建viewController第一个实例：

ViewController *viewController = [[ViewController alloc] init];
// set the frame, do other stuff..
[_window addSubview:viewController.view];

Answer 2

请先检查您的 AppDelegate 代码

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    self.viewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];

   /******
       YOUR CODE HERE

   ******/

    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];


    return YES;
}

Answer 3

好的，所以在玩了一些之后。我能够让应用程序运行，而无需更改应用程序委托。

不知道为什么他在教程中声明要这样做。

谢谢你的帮助。