I use the following code to bring up a view
-(IBAction) openSomeView{
SomeView *sv = [[SomeView alloc]initWithNibName:#"SomeView" bundle:nil];
[self presentModalViewController:sv animated:NO];
[sv release];
}
How can I detect if this view has been created already and if so, then just show it now create a new object?
Thanks
first declare in #interface
SomeView *sv;
and the you can check it
-(IBAction) openSomeView{
if(sv==nil)
sv = [[SomeView alloc]initWithNibName:#"SomeView" bundle:nil];
[self presentModalViewController:sv animated:NO];
[sv release];
}
You cannot create more than one instance using this code, since you present modally the view controller.
Else, you'd probably keep a member variable in your class and check it against nil.
EDIT: or you can implement the 'Singleton' design pattern, if that's the meaning you search.
I have a couple of heavy-weight view controllers in my app. Right now I'm handling this situation as follows:
save MyViewController to appDelegate
in "openSomeView" method I'm checking if MyViewController was already created, if no - create it:
-(IBAction) openSomeView {
MyAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
if ( !appDelegate.myViewController ) {
appDelegate.myViewController = [[SomeViewController alloc] initWithNibName:#"SomeViewController"
bundle:nil];
}
[self presentModalViewController:appDelegate.myViewController animated:NO];
}
Related
I would like to know a method for navigating from one page to another page onclick .I
have tried
[self.navigationController
pushViewController:self
.objectNewlist
animated:YES];
but it is showing the error
Incompatible pointer types sending 'newlistplist *' to parameter of type 'UIViewController *'
my main class file is a subclass of UIViewController
and the second class is a subclass of UITableViewController
can any one help me out with this problem?
You can use
UIViewController *yourViewController = [[YourViewControllerClass alloc] initWithNibName:#"<name of xib>" bundle:nil];
[self presentModalViewController:yourViewController animated:YES];
[yourViewController release];
In case the new view is also to be created programmatically, you can do that in the viewDidLoad method of YourViewControllerClass and change the initialization to
UIViewController *yourViewController = [[YourViewControllerClass alloc] init];
In YourViewController when you wish to come back to previous view on some button action you can use
[self dismissModalViewControllerAnimated:YES];
Another way that you can do is
UIViewController *yourViewController = [[YourViewControllerClass alloc] init];
[self addSubview:[yourViewController view]];
and to remove the view you can use
[self.view removeFromSuperview];
-(void)onClickButton
{
ViewControllerClass *objViewControllerClass = [ViewControllerClass alloc] init] ;
[self presentModalViewController:objViewControllerClass animated:YES];
[objViewControllerClass release];
}
objViewControllerClass (object of another class)
I'm not sure how to do this. So I originally had a ViewController that had one .xib, with one main view. I present it like this:
DogViewController *dvc = [[DogViewController alloc] initWithNibName:#"DogViewController" bundle:nil];
dvc.modalPresentationStyle = UIModalPresentationFormSheet;
dvc.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentModalViewController:dvc animated:YES];
[dvc release];
So that works fine. However now from a button press in the DogViewController.xib, I want to dismiss the current form sheet, and show another form sheet with some additional questions before proceeding. So I started by adding another view to in my original .xib of DogViewController, then got stuck in the logic of how to dismiss the first one, and show the second one. I'm assuming I need some outlet to the new view in the same .xib, but from there I'm lost. Thanks.
The way to do this would be to set it up with a UINavigationController as Mathiew mentions. However, if you really want to transition between two views on one view controller, you can refer to this sample code from Apple:
http://developer.apple.com/library/ios/#samplecode/ViewTransitions/Introduction/Intro.html
The code uses ImageViews to demonstrate the effect but I don't see why you can't use views instead :)
You can add a view within the other view in front of all of the other objects and just use its hidden property to control whether it's shown or not.
Why don't you use a navigation controller in your modal view, create another xib and do a [self.navigationController pushViewController:secondViewController animated:YES];
If you have a good reason, you can set a second view outlet secondView and use code like
UIView* superview = [self.view superview];
[self.view removeFromSuperView];
[superview addSubview:self.secondView];
Very simple solution is to hold reference to MainViewController and call methods on it that swap between two view controllers.
Like this:
#implementation MainViewController
- (void)showDogViewController {
[self dismissModalViewControllerAnimated:YES];
DogViewController *dvc = [[DogViewController alloc] initWithNibName:#"DogViewController" bundle:nil];
dvc.modalPresentationStyle = UIModalPresentationFormSheet;
dvc.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
dvc.mainViewController = self;
[self presentModalViewController:dvc animated:YES];
[dvc release];
}
- (void)showCatViewController {
[self dismissModalViewControllerAnimated:YES];
CatViewController *cvc = [[CatViewController alloc] initWithNibName:#"CatViewController" bundle:nil];
cvc.modalPresentationStyle = UIModalPresentationFormSheet;
cvc.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
cvc.mainViewController = self;
[self presentModalViewController:cvc animated:YES];
[dvc release];
}
}
#end
#implementation DogViewController
- (void)showCatViewController {
[mainViewController showCatViewController]
}
#end
#implementation CatViewController
- (void)showDogViewController {
[mainViewController showDogViewController]
}
#end
I'm developing an iPhone 3.1.3 app with iOS 4 SDK.
I have two ViewControllers, mainViewController and AboutViewController.
I use this code to go from mainViewController to AboutViewController (code inside mainViewController.m):
- (IBAction) aboutClicked:(id)sender
{
AboutViewController* aboutController =
[[AboutViewController alloc]
initWithNibName:#"AboutViewController"
bundle:nil];
[self.view addSubview:aboutController.view];
[aboutController release];
}
And this to come back from AboutViewController to mainViewController (code inside AboutViewController.m):
- (IBAction) backClicked:(id) sender
{
[self.view removeFromSuperview];
}
When I click on Back Button on AboutViewController, I get an EXC_BAD_ACCESS.
I'm using a window-based application template.
I've also tried to add a breakpoint in [self.view removeFromSuperview] but I can't.
Do you know why?
Do this instead:
- (IBAction) aboutClicked:(id)sender
{
AboutViewController* aboutController =
[[AboutViewController alloc]
initWithNibName:#"AboutViewController"
bundle:nil];
[self presentModalViewController:aboutController animated:YES];
[aboutController release];
}
And this to come back from AboutViewController to mainViewController (code inside AboutViewController.m):
- (IBAction) backClicked:(id) sender
{
[[self parentViewController] dismissModalViewControllerAnimated:YES]
}
The reason why you get EXC_BAD_ACCESS is because after adding the view of a viewController as sub view you released the controller, hence the touch event couldn't see the intended viewController to process it.
comment out the release statement like below and it should work
- (IBAction) aboutClicked:(id)sender
{
AboutViewController* aboutController =
[[AboutViewController alloc]
initWithNibName:#"AboutViewController"
bundle:nil];
[self.view addSubview:aboutController.view];
//[aboutController release]; To avoid leaking consider creating aboutController variable at instance level and releasing it in the dealloc.
}
Try:
[self presentModalViewController:aboutController animated:YES];
To present the view and:
[self dismissModalViewControllerAnimated:YES];
To remove the view...
1) Make aboutController a class level variable
2) Create a delegate method to handle
(IBAction) backClicked:(id) sender
3) In implementation of delegate call
[aboutController.view removeFromSuperView];
I'm sure this is some stupid mistake, but i'm trying for the past hour to remove a subview from my superview without any success.
On my first view i'm having
UIViewController *helpView = [[[UIViewController alloc] initWithNibName:#"HelpView" bundle:nil] autorelease];
[self.view addSubview:helpView.view];
And then inside helpView i have a button which is connected to an IBAction called "closeHelp" which just does the following:
- (IBAction) closeHelp{
[self.view removeFromSuperview];
}
But this causes my app to crash with EXC_BAS_ACCESS for some weird reason, even those this is inside the HelpView, meaning self.view should be pointed to the correct subview..
Would appreciate your help
Thank you.
Shai.
As Andreas answered, you are trying to remove self.view from its super/parent view.
You basically need to remove the helpView from its parent view.
so it should be
- (IBAction) closeHelp{
[helpView removeFromSuperview];
}
But we dont know what is "helpView" in the above method. As we dont have any handle for it.
So our code should finally look like this.
#define HELP_VIEW_TAG 101 // Give tag of your choice
HelpView *helpView = [[HelpView alloc] initWithNibName:#"HelpView" bundle:nil];
helpView.view.tag = HELP_VIEW_TAG;
[self.view addSubview:helpView.view];
[helpView release];
- (IBAction) closeHelp{
UIView *helpView = [self.view viewWithTag:HELP_VIEW_TAG];
[helpView removeFromSuperview];
}
The self.view does not point to your subview but the root view which your uiviewcontroller manages. You should probably remove only the last object in the subview stack, not the whole view, because now you are removing the whole help view.
Anyway, why do you not present the viewcontroller modally instead of doing this?
[self presentModalViewController:helpView animated:NO/YES];
helpView. modalTransitionStyle = //One of the constants below
UIModalTransitionStyleCoverVertical
UIModalTransitionStyleFlipHorizontal
UIModalTransitionStyleCrossDissolve
UIModalTransitionStylePartialCurl
Usually I am writing self.modalTransitionStyle = // One of the constants
in the viewcontroller which will be presented modally, instead of spreading the code.
You are initializing helpView as a UIViewController.
Make sure you have #import "HelpView.h" (or whatever the helpView .h file is called) in the .h file of the view controller where you are initializing it.
Then, use this code:
HelpView *helpView = [[HelpView alloc] initWithNibName:#"HelpView" bundle:nil];
[self.view addSubview:helpView.view];
That should fix it.
The easiest solution for me eventually was to just define my XIB's file owner as the same class as the parent controller, meaning the parent controller would control both the parent and the subview, which just makes a lot easier. :)
Declare the help view on calss level.
in.h file
#class HelpView;
..
#interface
{
HelpView *helpView;
}
#property(nonatomic,retain)HelpView* helpView;
In.m file
#import "HelpView"
#synthensize helpView;
now add this Code where you want
helpView = [[HelpView alloc] initWithNibName:#"HelpView" bundle:nil];
helpView.view.tag = HELP_VIEW_TAG;
[self.view addSubview:helpView.view];
- (IBAction) closeHelp{
//UIView *helpView = [self.view viewWithTag:HELP_VIEW_TAG];
[helpView removeFromSuperview];
}
-(void)dealloc
{
[helpView release];
}
In my subclass of NSObject I would like to call something like
[[self navController] presentModalViewController:myView animated:YES];
But none of my tries were successful. How can I call a modal view if I'm not in a subclass of UIViewController?
Solution:
#import "myProjectNameAppDelegate.h"
// ...
MyViewController *myView = [[MyViewController alloc] init];
myProjectNameAppDelegate *appDelegate = (myProjectNameAppDelegate *)[[UIApplication sharedApplication] delegate];
[[appDelegate navController] presentModalViewController:myView animated:YES];
better way to call a presentModalViewController is, passing viewcontroller to the NSobject class. call the nsobject function from the uiviewcontroller
Here is the code with mail example
In view Controller //your current view
[nsobjectclassObject OpenMailComposer:self]; //this will take the viewcontroller to NSobject class
In NSObject class //may be sharing class
-(void)OpenMailComposer:(UIViewController*)view
{
viewControllertoShow = view; // viewControllertoShow is UIVIewcontroller object
MFMailComposeViewController *mailView = [[MFMailComposeViewController alloc]init];
mailView.mailComposeDelegate = self;
[mailView setSubject:#"Hey! check this out!"];
[viewControllertoShow presentModalViewController:mailView animated:YES];
}
For dismissing from NSObject class you can do the following
[viewControllertoShow dismissViewControllerAnimated:YES]
I don't see a way to display a modal view without a ViewController. You have to store a reference to a UIViewController in your class so you can access it. Or setup a property in your AppDelegate, which you can get by calling [[UIApplication sharedApplication] delegate];
If you hold the navigationController or some viewController, you can present a modal view controller.
What is your myView? Is it a view, is it a viewController. I hope that it is a viewcontroller otherwise, this is the reason your code doesn't run