将UIPickerView链接到NSTimer iOS

Question

I am building an app similar to snapchat where we take a picture or video and then it destructs after a certain amount of time.

I am implementing a UIPicker within the camera module and once the user take a picture they select a time for how long the recipient sees the picture, then the user sends the image that self destructs after 1-10 seconds.

How can I link the UIPicker to the NSTimer which is another class?

camera.h

@property (strong, nonatomic) IBOutlet UIPickerView *timePicker;
@property (nonatomic, strong) NSArray *pickerData;


picker data in camera.m file:
interface //
{
 int secs;
}
@end

- (void)viewDidLoad {
    [super viewDidLoad];

    self.pickerData = @[@"1 second", @"2 seconds", @"3 seconds", @"4 seconds", @"5 seconds", @"6 seconds", @" 7 seconds", @" 8 seconds", @" 9 seconds", @" 10 seconds"];

    self.timePicker.dataSource = self;
    self.timePicker.delegate = self;
}

-(long)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    return 1;
}

-(long)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
    return self.pickerData.count;
}

- (NSString*)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    return self.pickerData[row];
}

 -(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
            {
               //help here please
            }
- (IBAction)next:(id)sender {
//goes to select friends page
}

image.m file where image is displayed for the user: this image should destruct after the amount of time the user selects from the picker.

-(void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];

    if ([self respondsToSelector:@selector(timeout)]) {

    [NSTimer scheduledTimerWithTimeInterval:7 target:self selector:@selector(timeout)
                                   userInfo:nil repeats:NO];

    }

}

[timeout pops to root view]

I need to let the user select a time on the picker and then for the image in the image.m file to destruct after that amount of time.

The user take a picture then below the picture is the pickerview the user selects a time and presses next to go to select friends. half of the screen is the picture the other half is the UIPickerView

Answer 1

Just pass the data to the second view controller, the one displaying the image. Something like this :

-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    // leave this empty

}

- (void)buttonHandler:(UIButton *)sender {
    image *iVC = [[image alloc] init];
    iVC.seconds = [self.timePicker selectedRowInComponent:0];

    [self presentViewController:iVC animated:YES];
}

And in ImageViewController.h you'd need something like this :

@interface image : UIViewController

@property (nonatomic, assign) NSUInteger seconds;

@end

Then just use the value passed in seconds property to time your timer in viewDidLoad in camera.m

Answer 2

Why you don't just present the image view controller once the user select the the duration from the picker and pass the value of seconds as property of the destination view controller . check Losiowaty answer

If you have a special case for example the view controller that you want to inform is already created and it's not your current view controller that is responsible of creating and presenting it then NSNotificationCenter will inform any object that has registered to observe the notification of selecting and sending the photo. We can create a notification called for example didSendPhoto and any object can observe and receive a notification once a user send a photo, we an pass data also in our case the duration.

An NSNotificationCenter object (or simply, notification center) provides a mechanism for broadcasting information within a program. An NSNotificationCenter object is essentially a notification dispatch table.

NSNotificationCenter Class Reference

So When the user select the amount of time and send the image you post a notification with the duration as userInfo

 // instead 50 put the choice of the user from the picker 
NSDictionary *userInfo = [NSDictionary dictionaryWithObject:@(50) forKey:@"durationBySeconds"];
 // post the notification 
[[NSNotificationCenter defaultCenter] postNotificationName: @"didSendPhoto"
                                                    object:nil
                                                  userInfo:userInfo];

Now from where you want to scheduledTimerWithTimeInterval add observer for the notification previously created

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(didSendImage:)
                                             name:@"didSendPhoto"
                                           object:nil];

then implement the method

-(void) didAddReview:(NSNotification *) notification
{
    NSNumber *seconds = (NSNumber *)[notification.userInfo objectForKey:@"durationBySeconds"];


  [NSTimer scheduledTimerWithTimeInterval:  [seconds integerValue]
                         target:self
                       selector:@selector(timeout)
                       userInfo:nil
                        repeats:NO];
     [timeout method pops to rootview]

}

Answer 3

You need to take property for storing the selected value from picker view

camera.h

#import "AppDelegate.h"

say at AppDelegate

@property (readwrite, nonatomic) int secondsValue;

camera.m

ViewDidLoad Method

appDelegate= (AppDelegate *)[[UIApplication sharedApplication] delegate];


-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
    {
       //help here please
       appDelegate.secondsValue=(int)[self.pickerData objectAtIndex:row];

    }

image.h

#import "AppDelegate.h"

image.m

appDelegate= (AppDelegate *)[[UIApplication sharedApplication] delegate];



[NSTimer scheduledTimerWithTimeInterval:appDelegate.secondsValue
                             target:self
                           selector:@selector(timeout)
                           userInfo:nil
                            repeats:NO];

This can link Picker View selection to NSTimer..! Hope it helps you..!