I declare a a uiview in my header file of a uiviewcontroller like so:
#property (strong, nonatomic) UIView *loadLoading;
And initiate itin viewdidload:
loadLoading = [[UIView alloc] initWithFrame:self.view.bounds];
loadLoading.backgroundColor = [UIColor blueColor];
[self.view addSubView:loadLoading];
This works fine. But at another point in my program i want to remove this subview. But for some reason, it doesnt get removed.
NSLog(#"%#",loadLoading.backgroundColor);
[loadLoading removeFromSuperview];
(I know it gets to that point and loadLoading is accessible because the log does work.
If you are getting the NSLog(#"%#",loadLoading.backgroundColor); worked.
Then this code [self.loadLoading removeFromSuperview]; should be work, else there is some weird bug.
Here is another approach:
Add a tag to the view when you add it to the parentView.
loadLoading = [[UIView alloc] initWithFrame:self.view.bounds];
[loadLoading setTag:7];
Use that tag to remove it from the parentView.
[[self.view viewWithTag:7] removeFromSuperView];
Found the issue.
I didnt provide enough details in my question. I was calling this method from notificationcenter, which loads on a different thread. So i had to first do performSelectorOnMainThread which worked
Try:
[self.loadLoading removeFromSuperview];
Related
In a controller I'm creating a UIScrollView. I'm trying to set this viewcontroller as the UISCrollview delegate and to implement the delegate's method in order to add (later) a UIPageControl.
I've read a bit, and found this link, this other link and other here on SO, and some useful tutorial all around the web, but I don't understand what I'm doing wrong. Everytime a scroll the UIScrollView, the app crashes with an EXC_BAD_ACCESS error.
Here's my .h file
#import <UIKit/UIKit.h>
#interface StatsViewController : UIViewController <UIScrollViewDelegate> {
UIScrollView *scrollView;
UIPageControl *pageControl;
}
#end
Then in my .m file, I'm creating the scrollview and trying to define the delegate method like this:
- (void)viewDidLoad {
[super viewDidLoad];
NSInteger boxWidth = self.view.frame.size.width;
NSInteger boxHeight = 412;
scrollView = [ [UIScrollView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, boxHeight)];
scrollView.pagingEnabled = TRUE;
scrollView.delegate = self;
NSInteger numberOfViews = 2;
StatBreatheCounter *breatheCounter = [ [StatBreatheCounter alloc] init];
breatheCounter.view.frame = CGRectMake(0, 0, boxWidth, boxHeight);
[scrollView addSubview:breatheCounter.view];
BreatheLocationViewController *breatheLocation = [ [BreatheLocationViewController alloc] init];
breatheLocation.view.frame = CGRectMake(320, 0, boxWidth, boxHeight);
[scrollView addSubview:breatheLocation.view];
scrollView.contentSize = CGSizeMake(self.view.frame.size.width * numberOfViews, boxHeight);
[self.view addSubview:scrollView];
}
- (void)scrollViewDidScroll:(UIScrollView *)sender {
NSLog(#"RUNNING");
}
...but every time I slide on the scroll view, the app is crashing.
Now, I'm quite a n00b on Ojective-C, but I feel I'm missing something. Browsing around everything points on the fact that the delegate could be deallocated early, and when the user trigger the action, no one is handling the method (sorry for the explanation :)).
...but if the delegate it's the viewcontroller itself, how could it be deallocated?
As you can see, I'm quite confused :(
Any help would be really appreciated
--
EDIT:
I'm going to include here the solution founded thanks with your comments and answer.
When I posted my question I was so convinced that the error was coming from the way I was creating the UIScrollView and setting its delegate that I didn't realize that the problem was (as everything was suggesting, btw :)) I was allocating the StateViewController in its parent without declaring any "strong" reference to it (again, sorry for the explanation, I'm really a n00b in this).
Thanks a lot for your helping in pointing me on the right direction
It looks like you are losing reference to the delegate during scroll. I would look into any other release events around StatsViewController or other events that could cause it to be dereferenced.
I'm trying to move a uiLabel down a drop if it's an iPhone 5 (4" display). But it's not working when the code is in viewDidLoad. If I call the code from clicking a uiButton, it works. Here's the code:
-(void) viewDidLoad {
if(CGSizeEqualToSize([[UIScreen mainScreen] preferredMode].size,CGSizeMake(640, 1136))) {
CGRect frame = [self.timeOnCurrentQuestion frame];
frame.origin.y += 40; // change the location
[self.timeOnCurrentQuestion setFrame:frame];
nslog(#"This DOES get logged");
}
}
Jonah, have you tried your code in viewWillAppear method? Possibly, it'll sort-out your issue.
Maybe that are something you need to beware of.
- (void)viewDidLoad
It is a method that when the controller juz created its view.
for example:
maybe in your init method, you call something like:
[self.view setBackground:[UIColor redColor]];
self.timeOnCurrentQuestion = [[UIView alloc] initWithFrame:kFrame];
In this case the work flow will be like this:
[self.view setBackground:[UIColor redColor]];
[self viewDidload];
self.timeOnCurrentQuestion = [[UIView alloc] initWithFrame:kFrame];
Th reason for this work flow is because the self.view is called, then its view is needed before the normal view cycle, so , in this case, self.timeOnCurrentQuestion is still nil in the viewDidload method.
I don't know if my practice is the best or not.
I always init the subView in the controller's init method.
and do the [self.view addSubview:_subview] (//or everything method call that require the self.view) in [self viewDidload];
viewDidAppear worked for me. The life cycle seems to be
LoadView()
viewDidLoad()
viewWillAppear()
viewDidAppear()
I have added a UIWebview to the cell's content view
UIWebView *webview = [UIWebView alloc]init];
[cell.contentView addSubview:webview];
Now I intend to remove 'webview' from the cell's contentview.
Can I do the following?
Method 1:
[webview removeFromSuperview];
Or do I really need to loop through all the subviews of the contentview before removing it?
Method 2:
for (UIView *subview in [self.contentView subviews])
{
if ([subview isKindOfClass:[UIWebView class]])
{
[subview removeFromSuperview];
}
}
I tried method 1 and it didn't seem to work, am not sure if I am missing something or if method 2 is the only way to go
Method 1 should work, but are you sure that the web view you're removing is really the same as the one you added? A simple way to remove a given subview from a view is to assign a tag:
//...
webView.tag = 123;
[cell.contentView addSubview:webView];
//...
[[cell.contentView viewWithTag:123] removeFromSuperview];
In practice it would of course be better to use a named constant as the tag.
//creating
// cell.bounds will fill up the cell with your webview
UIWebView *webview = [[UIWebView alloc]initWithFrame:cell.bounds];
webview.tag = 11;
[cell.contentView addSubview:webview];
//removing
[[cell.contentView viewWithTag:11] removeFromSuperview];
You can just use removeFromSuperview. What do you mean by "didn't seem to work?" The most likely problem is that webview is nil at the point that you called removeFromSuperview (or is pointing to some other view). Make sure it's pointing to the view you mean.
I believe that your webview is nil when actually trying it to remove from the superview. Have you tried reloading table data after removing it from the content view? In which methods are you doing view manipulation? Datasource/delegate or custom IBActions?
I'm new to Objective-C, so the way I'm going about this might be ludicrous, but here goes:
I have a login form in my iPhone application. When the user has entered their credentials, they hit Done in the top right corner, which triggers an IBAction and a custom progress indicator pops up. I've created this indicator by using a class containing an instance method named showProgressIndicator. showProgressIndicator creates and returns a UIView, which I then add to my view like so:
ProgressIndicatorElement *ProgressIndicator = [[ProgressIndicatorElement alloc] init];
box = [ProgressIndicator showProgressIndicator];
[self.view addSubview:box];
I have of course declared box as a UIView in my header file. The progress indicator pops up beautifully and in the meantime I'm doing a behind-the-scenes URL request that, when finished, calls another method in my view controller named receivedServerResponse. Now, what I want to do is to remove the progress indicator, which is why I'm doing this:
- (void)receivedServerResponse {
[box removeFromSuperview];
}
But nothing happens at all. I'm not getting any errors or warnings, and the code is being highlighted just as if everything was running smoothly. I've tried retaining the indicator in my IBAction, but that doesn't help either.
Hope you can help out!
Updated:
Here is the showProgressIndicator method:
- (UIView *)showProgressIndicator {
box = [[UIView alloc] initWithFrame:CGRectMake(85, 190, 210, 140)];
box.backgroundColor = [UIColor colorWithRed:0.0 / 255 green:0.0 / 255 blue:0.0 / 255 alpha:.6];
box.layer.cornerRadius = 8;
UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
spinner.layer.frame = CGRectMake((box.layer.bounds.size.width - spinner.layer.bounds.size.width)/2, 20, spinner.layer.bounds.size.width, spinner.layer.bounds.size.height);
[spinner startAnimating];
[box addSubview:spinner];
UILabel *titleInBox = [[UILabel alloc] initWithFrame:CGRectMake(0, 65, 150, 20)];
titleInBox.font = [UIFont boldSystemFontOfSize:16];
titleInBox.textColor = [UIColor whiteColor];
titleInBox.textAlignment = UITextAlignmentCenter;
titleInBox.backgroundColor = [UIColor clearColor];
titleInBox.text = #"Authorizing...";
[box addSubview:titleInBox];
return box;
}
Second update:
#Deepak just pointed out in the comments that I might be running two different instances of my view controller, which actually seems to be the case. In the external class that handles the aforementioned URL request, I get back to the view controller's receivedServerResponse method by doing this:
- (void)requestFinished:(ASIHTTPRequest *)request {
NSString *responseString = [request responseString];
SignInViewController *viewController = [[SignInViewController alloc] init];
[viewController receivedServerResponse];
}
Without spreading myself too thin (probably too late ;)), ASIHTTPRequest is set up so that if you call one method that performs an asynchronous URL request, a predefined method called requestFinished (above) is called, which is why I've had to call my view controller this way, because I can't access the returned value in an easier way (that I know of).
Creating a new instance of SignInViewController is not the correct way. It only seems correct to maintain a weak reference (assigned property) of the SignInViewController object. Say your class is RequestHandler.
#interface RequestHandler: [..] {
}
#property (nonatomic, assign) SignInViewController * signInViewController;
#end
#implementation RequestHandler
#synthesize signInViewController;
[..]
- (void)requestFinished:(ASIHTTPRequest *)request {
NSString *responseString = [request responseString];
[signInViewController receivedServerResponse];
}
#end
So when you're creating a RequestHandler object within the SignInViewController instance, you do,
RequestHandler * requestHandler = [[RequestHandler alloc] init];
requestHandler.signInViewController = self;
[..]
Note, you can also look at delegation and notifications.
I think part of the problem may be with memory management. If showProgressIndicator does not return an autoreleased object, try releasing box after adding it as a subview, like so:
[self.view addSubview:box];
[box release];
box may not disappear if box is not deallocated when removed from the superview.
My other recommendation is that instead of doing it the way you are doing, creating a view, adding it, and then trying to removing it, you might want to try adding box as a subview when the login view is created and setting its hidden property to YES then unhiding it later when necessary.
Based on your update: You have some memory management issues in showProgressIndicator. Whenever you alloc an object, you should release it. In this case, release all of your variables after adding them as subviews as I mentioned above. box however should be returned as an autoreleased object since showProgressIndicator does not know when it will need to be released. For that you should replace return box; with return [box autorelease];
You need to send the activity indicator a stopAnimating message when you want the animation to stop. There's no need to remove it from its superview; instead, simply make sure that its hidesWhenStopped property is set to YES.
How about adding box view on window in appDelgate? Give a tag to your boxView and in the remove method get the boxView back by using tag. For example if you give tag 99
- (void)receivedServerResponse {
UIView *box = [window viewWithTag:99];
[box removeFromSuperview];
}
also you don't need to declare an instance variable in header file. and you can access progress indicator anywhere in the application.
Without spreading myself too thin (probably too late ;)), ASIHTTPRequest is set up so that if you call one method that performs an asynchronous URL request, a predefined method called requestFinished (above) is called, which is why I've had to call my view controller this way, because I can't access the returned value in an easier way (that I know of).
ASIHTTPRequest calls -requestFinished: on the object you set as the request's delegate. You should design your classes such that this delegate object either has a reference to the view controller you want it to act on or has some means of notifying that view controller to take action.
The easiest solution might be to make the controller the request's delegate.
I understand modal views cover the entire screen. But I really want a view that covers only half the screen just like the keyboard. So, please tell me why this doesn't work
MyController *controller = [[MyController alloc] initWithNibName:#"MyView" bundle:nil];
CGRect frame = CGRectMake(0,44,768,264);
[controller view].frame = frame;
contoller.delegate = self;
[[self view] addSubView:[controller view]];
[controller release];
I am trying to add a sub view to my current view and make it appear where the keyboard appears.
It throws a BAD ACCESS exception
In my code (above), I was using a custom UIViewController with it's own view [set to UIView on IB]. I couldn't get it to work by setting frame for the view controller's view.
So I added a custom UIView without a Nib file with all the controls (buttons, textfields) added on initWithFrame.
MyCustomView = [[MyCustomView] alloc] initWithFrame:frame delegate:self];
[self.view addSubView:MyCustomView];
Thanks for your comment, Jacob.