I am loading UIViewcontroller from storyboard using instantiateviewcontroller method of UIStoryboard. As soon as this method is executed, viewDidLoad() method is called, even before initWithCoder. This behaviour is different and contradicts lazy loading.
Now, the problem is how to set properties on UIViewcontroller so that I can use them in viewDidLoad method ?
I'm not correctly understand you initial question.
But i think you want something like this
-(void) loadNewVC {
SampleViewController *sample = [[UIStoryboard storyboardWithName:#"Main" bundle:nil] instantiateViewControllerWithIdentifier:#"sample"];
NSData *birthData =[[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:#"http://iglesiasSite.com"]];
sample.someName = #"Enrique Iglesias";
sample.someData = birthData;
[[[UIApplication sharedApplication] keyWindow] setRootViewController:sample];
}
in header of SampleViewController.h class
#interface SampleViewController : UIViewController
#property (nonatomic, strong) NSString *someName;
#property (nonatomic, strong) NSData *someData;
#end
SampleViewController.m
- (void)viewDidLoad {
[super viewDidLoad];
[self processData: self.someData andName: someName];
}
Related
I have a table view controller called StackViewController, this is where I hold a list of todo's that has been created in CreateViewController...
I have an NSString property in StackViewController called currentTarget that represent the first to do in the stack:
import <UIKit/UIKit.h>
#interface StackTableViewController : UITableViewController
#property (nonatomic, strong) NSString *currentTarget;
#end
This property holds the first NSString object in the table view, I get it like this:
#import "StackTableViewController.h"
#import "Target.h"
#import "CoreDataStack.h"
#interface StackTableViewController () <NSFetchedResultsControllerDelegate>
#property (nonatomic, strong) NSFetchedResultsController *fetchedResultController;
#end
#implementation StackTableViewController
- (void)viewDidLoad {
[super viewDidLoad];
[self.fetchedResultController performFetch:nil];
NSIndexPath *indexPath = [NSIndexPath indexPathForItem:0 inSection:0];
Target *target = [self.fetchedResultController objectAtIndexPath:indexPath];
self.currentTarget = target.body;
}
Now, when I log into my home page which called HomeViewController I want to initiate the StackTableViewController and get its currentTatget property value...
I know that there are delegate to help you notify other views when a change has happened, but in my case I want to get this property value before even I have been in this page (StackTableViewController), because the HomeViewController is the first view controller that is loaded (my initial view controller) and I what to access this property when I was just logged in to the app and populate a label with it.
How should I do this?
I thought maybe something like this:
#import "HomeViewController.h"
#import "CreateViewController.h"
#import "StackTableViewController.h"
#interface HomeViewController ()
#property (strong, nonatomic) IBOutlet UILabel *targetLabel;
#end
#implementation HomeViewController
- (void)viewDidLoad {
[super viewDidLoad];
StackTableViewController *vc = [[StackTableViewController alloc] init];
NSString *current = vc.currentTarget;
self.targetLabel.text = current;
}
But i'm missing something here...my label is not populated...
I think there is something with the views lifecycle.
i'm a newbie please help me to figure this out...thanks
Don't do anything to do with graphics in viewDidLoad. The earliest you want to do it is in viewWillAppear (most of the time) and occasionally you will need to do it in viewDidAppear.
Try the same code in viewWillAppear and it should work.
Oh right, since your other viewController is setup in viewDidLoad, you need to call
[stackTableViewController view] on your stackTableViewController after you alloc init it. Seems weird, but this actually works. This is because the StackTableViewController doesn't have its calculation done when you initialize it, it runs through it in it's viewDidLoad delegate.
- (void)viewDidLoad {
[super viewDidLoad];
StackTableViewController *vc = [[StackTableViewController alloc] init];
[vc view];
NSString *current = vc.currentTarget;
self.targetLabel.text = current;
}
Im building an app that calls different subviews and lay them over in a main view controller (http://imgur.com/p6l9Oac)
when ever the user clicks a button on the bottom part of the screen (lets call it sliding menu!) the view behind it will disappear and new one will show up.
one of the subviews is Settings , which it have some switches to enable/disable some of the buttons.
in the SettingsViewController.
Ive set a protocol:
#protocol SettingsViewControllerDelegate <NSObject>
#required
-(void)hideCountdownView;
-(void)showCountdownView;
#end
and the interface contains:
#interface SettingsHubViewController : UIViewController
#property (weak, nonatomic) IBOutlet UISwitch *enableCountdown;
#property (nonatomic, assign) id <SettingsViewControllerDelegate> delegate;
#property (weak, nonatomic) IBOutlet UIView *mainView;
#end
and in the Implementation:
- (IBAction)switchAction:(id)sender {
if (!self.enableCountdown.on) {
NSLog(#"The view is Hidden");
[_delegate hideCountdownView];
} else if (self.enableCountdown.on) {
NSLog(#"The view is Shown");
[_delegate showCountdownView];
}
}
You can see i used _delegate to use the show and hide functions, I used NSLog to make sure that Im calling the functions correctly.
in the MainViewController
#import "SettingsHubViewController.h"
#interface MainViewController () <SettingsViewControllerDelegate>
#property (nonatomic, strong) SettingsHubViewController * settingsViewController;
and the Implementation
#implementation MainViewController
-(void)showCountdownView {
self.slidingMainMenuViewController.countdownView.hidden = NO;
NSLog(#"Showing Countdown");
}
-(void)hideCountdownView {
self.slidingMainMenuViewController.countdownView.hidden = YES;
NSLog(#"Hiding Countdown");
}
-(void)viewDidLoad {
[super viewDidLoad];
self.settingsViewController.delegate = self;
self.slidingMainMenuViewController.delegate = self;
}
the problem is that the NSLogs above is not being called at all, can any one help me ?
Thanks
UPDATE: Since i have more that 20 different views that needs to be called, i created this method
- (UIView *) getPresentedMenu:(NSString *) menuIdentifer withMenuTag:(int) menuTag withAViewController:(UIViewController*) menuViewController andMenuDelegate:(id) menuDelegate {
menuViewController = [[UIStoryboard storyboardWithName:#"Main" bundle:Nil] instantiateViewControllerWithIdentifier:menuIdentifer];
menuViewController.view.tag = menuTag;
if (self.viewBeingCalledBySwipe == NO) {
menuViewController.view.frame = CGRectMake(0, menuViewController.view.frame.size.height, menuViewController.view.frame.size.width, menuViewController.view.frame.size.height);
} else if (self.isItRightSwipe == YES) {
menuViewController.view.frame = CGRectMake(-menuViewController.view.frame.size.width, 0, menuViewController.view.frame.size.width, menuViewController.view.frame.size.height);
} else if (self.isItRightSwipe == NO) {
menuViewController.view.frame = CGRectMake(menuViewController.view.frame.size.width, 0, menuViewController.view.frame.size.width, menuViewController.view.frame.size.height);
}
[self.view addSubview:menuViewController.view];
[self addChildViewController:menuViewController];
[menuViewController didMoveToParentViewController:self];
UIView *view = menuViewController.view;
return view;
}
So when ever i need a certain view controller, i just call this function
self.childView = [self getPresentedMenu:#"Settings" withMenuTag:SETTINGS_TAG withAViewController:self.settingsViewController andMenuDelegate:self.settingsViewController.delegate];
but this method is not assigning the delegate
If settingsViewController is an IBOutlet, you have to add IBOutlet to it's declaration and connect it using the storyboard or xib.
#property (nonatomic, strong) IBOutlet SettingsHubViewController * settingsViewController;
But if it's not an Outlet, you have to allocate it before set it's delegate.
self.settingsViewController = [[SettingsHubViewController alloc] init];
self.settingsViewController.delegate = self;
You should also verify that your - (IBAction)switchAction:(id)sender IBAction is correctly connected in the storyboard or xib.
When you initialize your SettingsViewController, make sure that you do it using the storyboard method and not [[SettingsViewController alloc] init].
First set a Storyboard ID directly in your storyboard view:
Then use this to settingsViewController:
self.settingsViewController = [[UIStoryboard storyboardWithName:#"MainStoryboard_iPhone" bundle:NULL] instantiateViewControllerWithIdentifier:#"SettingsViewController"];
Replace MainStoryboard_iPhone with your Storyboard name.
Hope that helps!
// If u are using View controller
SettingsHubViewController *settingVC = [[UIStoryboard storyboardWithName:#"Main" bundle:nil] instantiateViewControllerWithIdentifier:#"yourStoryBoardIdentifier"];
settingVC.delegate = self;
// If u are using XIB load the NIB after that set the settingVC.delegate = self;
its working for me (I created OverLay view and loaded in main class)
Hoping someone had to solve related issues .. this is driving me nuts :/
My UITableViewController implements a custom delegate method:
.h
#protocol folderDelegate
#required
- (void)folderViewDidSelectPlan:(NSString*)planId;
#end
#interface FolderViewController : UITableViewController
#property (nonatomic, assign) id delegate;
#end
.m
#implementation FolderViewController
#synthesize delegate;
...
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
NSDictionary *row = [self->resultsPlan objectAtIndex:indexPath.row];
if ([delegate respondsToSelector:#selector(folderViewDidSelectPlan:)]) {
[delegate folderViewDidSelectPlan:[row objectForKey:#"id"]];
}
}
In my iPad's MainView I'm displaying this UITableView via UIPopoverController:
#interface ProjectViewController ()<folderDelegate>
...
- (void) selectPlan:(UIBarButtonItem*)sender
{
if([self->popoverSelectPlanController isPopoverVisible]){
[self->popoverSelectPlanController dismissPopoverAnimated:YES];
}
FolderViewController *folder = [[FolderViewController alloc] initWithStyle:UITableViewStyleGrouped withInstallation:self->_installationId withProjectId:self->_projectId withParentFolderId:#""];
folder.delegate = self;
UINavigationController *folderNavView = [[UINavigationController alloc] initWithRootViewController:folder];
self->popoverSelectPlanController = [[UIPopoverController alloc] initWithContentViewController:folderNavView];
[self->popoverSelectPlanController presentPopoverFromBarButtonItem:sender permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
}
And handling the delegate via:
- (void) folderViewDidSelectPlan:(NSString *)planId
{
NSLog(#"called");
}
However, folderViewDidSelectPlan never get's called - I'm really stuck here, hope anyone has an idea how to solve this.
Thanks a lot!
Try to change declaration of the property to:
#property (assign) id<folderDelegate> delegate;
And also use self.delegate instead of in your UITableViewController.m file every time instead of just delegate.
If you don't have to support iOS4 or less remove synthesise from UITableViewController.m.
I use this code, but "it works" doesn't happen.
DetailViewController.h
[#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>
#protocol ProtocolNameDelegate
-(void)DoSomething;
#end
#interface DetailViewController : UIViewController {
id<ProtocolNameDelegate> _delegate;
}
#property (strong, nonatomic) id<ProtocolNameDelegate> _delegate;
DetailViewController.m
#synthesize _delegate;
- (void)viewDidLoad
{
[super viewDidLoad];
[_delegate DoSomething];
}
MasterViewController.h
#interface MasterViewController : UITableViewController <ProtocolNameDelegate>
MasterViewController.m
-(void)DoSomething
{
NSLog(#"It works");
}
I think i have to add something like:
MasterViewController* mvc = [[MasterViewController alloc] init];
mvc._delegate = self;
But it gives an error, and by the way will it create another instance of MasterViewController?
Instead of
MasterViewController* mvc = [[MasterViewController alloc] init];
mvc._delegate = self;
write this,
DetailViewController* svc = [[DetailViewController alloc] init];
dvc._delegate = self;
You made mistake in implementation.
Abstract of implementation should be.
Create Protocol in DetailVC.
Create Property for Delegate, Synthesize, and make call.
Import DetailVC in MasterVC and include delegate in MasterVC.h
Implement protocol method in MasterVC.m
Create instance of DetailVC and assign DetailVCObj.delegate = self;
In MasterViewController.m, you need to allocate and intialise DetailViewController somewhere
DetailViewController* dvc = [[DetailViewControlleralloc] init];
dvc._delegate = self;
Also, because you have written [_delegate doSomething] in
DetailviewController's viewDidLoad method,
it means you must set dvc._delegate = self; in MasterViewController.m
before loading dvc's view (before addSubview or anything that loads view).
Alright, so this is an extension to a question I asked last night. I have a little firmer grasp on how data can be passed between view controllers using various techniques. I wanted to go the MVC route, and creating a Singleton class seems the closest concept similar to MVC.
Basically I created a simple app with two View Controllers and a singleton class. I am trying to pass the value of a text field into a UILabel. For whatever reason it isn't working. This is what my code looks like.
ViewController.h
#import <UIKit/UIKit.h>
#import "Model.h"
#import "ViewController2.h"
#interface ViewController : UIViewController {
NSString *text2pass;
}
#property (weak, nonatomic) IBOutlet UITextField *tf;
#property (weak, nonatomic) IBOutlet UILabel *btn;
- (IBAction)go:(id)sender;
#end
ViewController.m
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
#synthesize tf = _tf;
#synthesize btn = _btn;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
NSString *tfstring = _tf.text;
NSLog(#"string = %#",tfstring);
}
- (void)viewDidUnload
{
[self setTf:nil];
[self setBtn:nil];
[super viewDidUnload];
// Release any retained subviews of the main view.
}
- (IBAction)go:(id)sender {
NSLog(#"btn pressed");
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"MainStoryboard" bundle:nil];
ViewController2 *vc2 = (ViewController2 *) [storyboard instantiateViewControllerWithIdentifier:#"home"];
text2pass = _tf.text;
[self passValues];
[self presentModalViewController:vc2 animated:YES];
}
-(void) passValues {
Model *model = [Model sharedModel];
model.passedText = text2pass;
}
#end
ViewController2.h
#import <UIKit/UIKit.h>
#import "ViewController.h"
#interface ViewController2 : UIViewController {
NSString *passedText;
}
#property (nonatomic)NSString *passedValue;
#property (weak, nonatomic) IBOutlet UILabel *lbl;
- (IBAction)back:(id)sender;
#end
ViewController2.m
#import "ViewController2.h"
#interface ViewController2 () {
NSString *passedtext;
}
#end
#implementation ViewController2
#synthesize lbl = _lbl;
#synthesize passedValue = _passedValue;
- (void)viewDidLoad
{
// do code stuff here
NSLog(#"passedText = %#",passedText);
_lbl.text = passedText;
[super viewDidLoad];
}
- (void)viewDidUnload
{
[self setLbl:nil];
[super viewDidUnload];
// Release any retained subviews of the main view.
}
- (IBAction)back:(id)sender {
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"MainStoryboard" bundle:nil];
ViewController *vc = (ViewController *) [storyboard instantiateViewControllerWithIdentifier:#"welcome"];
[self presentModalViewController:vc animated:YES];
}
#end
Model.h
#import <Foundation/Foundation.h>
#interface Model : NSObject {
NSString *passedText;
}
#property (nonatomic, strong) NSString* passedText;
+ (Model *) sharedModel;
#end
Model.m
#import "Model.h"
#implementation Model
#synthesize passedText = _passedText;
static Model *sharedModel = nil;
+ (Model *) sharedModel {
#synchronized(self){
if (sharedModel == nil){
sharedModel = [[self alloc] init];
}
}
return sharedModel;
}
#end
The project can be downloaded in its entirety from here http://chrisrjones.com/files/KegCop-Test.zip
If you know why the UILabel is not displaying the text field text let me know. Oh I pretty much followed this -> http://www.youtube.com/watch?v=ZFGgMPcwYjg&feature=plcp
Your addressing, and memory management is just plain... off. Firstly, there's absolutely no reason to create a singleton for this, but that's beside the point here.
Secondly, when declaring properties, (atomic, assign) is defaulted to if not otherwise specified, which means your string:
#property (nonatomic)NSString *passedValue;
is weak sauce, ripe for deallocation and destruction at a moments notice. Declare it copy, strong, or retain.
Thirdly, there's absolutely no reference to your singleton in the pushed view controller, yet you seem to have the belief that objects that are named the same in different classes retain their value (especially when #import'ed). Not so. You need to reference your singleton and pull the value of [Model sharedModel].passedText into that text field.
In fact, I fixed your sample in two lines:
//ViewController2.m
#import "ViewController2.h"
//actually import the singleton for access later
#import "Model.h"
#interface ViewController2 () {
NSString *passedtext;
}
#end
#implementation ViewController2
#synthesize lbl = _lbl;
#synthesize passedValue = _passedValue;
- (void)viewDidLoad
{
// do code stuff here
NSLog(#"passedText = %#",passedText);
//actually reference the singleton this time
_lbl.text = [Model sharedModel].passedText;
[super viewDidLoad];
}
- (void)viewDidUnload
{
[self setLbl:nil];
[super viewDidUnload];
// Release any retained subviews of the main view.
}
- (IBAction)back:(id)sender {
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"MainStoryboard" bundle:nil];
ViewController *vc = (ViewController *) [storyboard instantiateViewControllerWithIdentifier:#"welcome"];
[self presentModalViewController:vc animated:YES];
}
#end
Which yields this:
I wouldn't recommend using a Singleton as a good way to pass data around your application. Most apps are simple enough that this kind of central access is not necessary, and it usually creates a maintenance nightmare... but I don't think the fact that you're using a Singleton is actually important to getting your code working.
Assuming you have access to the data in ViewController1, in your case through the a Singleton instance of Model (which needs a more descriptive name), then all you have to do is pass through the data to ViewController2 when it is created and presented, which eliminates the need for a Singleton at all.
Once you create the controller, set the data you need, and then present the view controller - which is basically what you're doing anyway.
As to why it's not working: Is the view controller being presented, just not with the correct data? Or is there actually an issue presenting the controller at all? I would set a breakpoint in the go: action of ViewController1, make sure the data you expect is in the textfield, correctly populates the Model and that the value is correctly pulled out of the Model in ViewController2.
Unless you've removed some of the code, it looks like you correctly populate the Model property in ViewController1, but in ViewController2 you refer to a local ivar passedTextrather than pulling it from the model.
On a separate note, the way to go back from a presented modal view controller is usually to dismiss that controller, not to re-create the initial controller and present that over the top.