While changing between different views in an iPhone application I'm developing, I add and remove subviews from a larger view. I have written code which works on the iPod 4, iPhone 3, iPad 1, iPad 2, as well as the simulators. However, I get a bad access error on the iPhone 4 with the removeFromSuperView call. I know that its probably because I over released something so the superview no longer exists, but how is it that it worked on all the other devices?
// Try to do like following -
if(subview.superview!=nil)
[subview removeFromSuperview];
//--------------------------------------------------------------
// If you have more view's then check view like this -
for(UIView * subview in self.view) {
if(subview == view1) {
if(subview.superview!=nil)
[subview removeFromSuperview];
}
else if(subview == view2){
if(subview.superview!=nil)
[subview removeFromSuperview];
}
.
.
.
}
Related
I am using the following code to remove the toolbar from the iPhone keyboard when it is displayed.
- (void) keyboardDidShowNotification:(NSNotification *)aNotification {
NSArray *array = [[UIApplication sharedApplication] windows];
for (UIWindow* wind in array) {
for (UIView* currView in wind.subviews) {
if ([[currView description] hasPrefix:#"<UIPeripheralHostView"]) {
for (UIView* perView in currView.subviews) {
if ([[perView description] hasPrefix:#"<UIWebFormAccessory"]) {
[perView removeFromSuperview];
}
}
}
}
}
}
This is removing the toolbar like I want but it is still leaving a 1px border above where the toolbar use to be. How do I remove that as well?
Also this only appears to be an issue on iPhone Retina displays. iPhone 3GS and iPad Retina do not have it.
Seems to be a bug in removeFromSuperView. I had the same problem when adding a toolbar as an input accessory view to some pickers for inline editing. Calling 2x removeFromSuperView left the border.
Using [self.view endEditing:YES] when closing the picker helped to clean up the picker and the accessory view attached to it, with no border. Perhaps this can point you into the right direction?
I noticed an strange issue with my application that only occurs on the iPhone 3G and iPhone 3GS. I am creating a scroll view with two pages. On the second page of the scroll, when you try to scroll the picker, it is very unresponsive. It kinda appears that my application can't distinguish between the scrolling of the picker and the scrolling of the scrollview, because sometimes you scroll up and it goes to the left.
Please keep in mind, this works great on the iPhone 4 and iPhone 4S.
Has anyone ran into this problem before or any idea of what is actually going on?
Apparently the UIScrollView and UIPickerView cause problems if used together. However, this only occurred on the iPhone 3 and iPhone 3GS.
The solution was to subclass UIScrollView and implement the following method.
- (UIView *)hitTest:(CGPoint)point
withEvent:(UIEvent *)event
{
UIView *result = [super hitTest:point withEvent:event];
if ([result.superview isKindOfClass:[UIPickerView class]]) {
self.canCancelContentTouches = NO;
self.delaysContentTouches = NO;
}
else {
self.canCancelContentTouches = YES;
self.delaysContentTouches = YES;
}
return result;
}
You should only enable armv7 in your build settings (not armv6), that's all
Add a UIView over scroll view, over UIView add UIPickerView.
I'm testing iAds in XCode 4.
Everything works fine, until the first time a bannerView:didFailToReceiveAdWithError: is received, which I react to by sliding the banner off the screen.
//move the ad back off the screen if an error occurs
- (void)bannerView:(ADBannerView *)banner didFailToReceiveAdWithError:(NSError *)error {
if (self.bannerIsInScreenBounds)
{
[UIView beginAnimations:#"animateAdBannerOff" context:NULL];
// move the banner view off the screen.
banner.frame = CGRectOffset(banner.frame, 320, 0);
[UIView commitAnimations];
}
}
After that, no more bannerViewDidLoadAd: messages are sent to the ADBannerViewDelegate. I'm logging that method right at the top, it's not being called any more.
I'm not releasing the banner or anything, and the ADBannerViewDelegate class is still there and doing other stuff.
What could be wrong?
Thanks.
Why do you expect it load adverts after an error has happened - I think this is the correct behavior.
Looking at the comments it show that the error is "The operation couldn’t be completed. Ad inventory unavailable".
How do you expect it to give you adverts if it can't find any adverts to give ;)
OK, not an ideal solution but here's what I ended up doing.
Whenever I get a didFailToReceiveAdWithError, I wait 10 seconds (to avoid spamming with failures) then recreate the banner.
-(void)replaceAdView {
UIView *adViewSuperview = [adView superview];
[adView removeFromSuperview];
[adView release];
//starting off the screen again
adView = [[NSClassFromString(#"ADBannerView") alloc] initWithFrame:CGRectMake(320, 382, 320, 50)];
adView.delegate = self;
if (adViewSuperview) {
[adViewSuperview addSubview:adView];
}
self.bannerIsInScreenBounds = NO;
}
As my comment at how to implement AdBannerview and ADBannerview delegate, running iphone app in ipad simulator I got didFailToReceiveAdWithError immediately on setting the ADBannerView delegate, and never another delegate call. Running it on the iphone simulator (or changing the app target to universal) the delegate only got called after adding ADBannerView as a subview, and then delegate calls every 30 secs after that.
This is more of a general question for people to provide me guidance on, basically Im learning iPad/iPhone development and have finally come across the multi-orientation support question.
I have looked up a fair amount of doco, and my book "Beginning iPhone 3 Development" has a nice chapter on it.
But my question is this, if I was to programatically change my controls (or even use different views for each orientation) how on earth to people maintain their code base? I can just imagine so many issues with spaghetti code/thousands of "if" checks all over the place, that it would drive me nuts to make one small change to the UI arrangement.
Does anyone have experience handling this issue? What is a nice way to control it?
Thanks a lot
Mark
I do this with two simple methods in my view controller:
- (void) willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
[self adjustViewsForOrientation:toInterfaceOrientation];
}
- (void) adjustViewsForOrientation:(UIInterfaceOrientation)orientation {
if (orientation == UIInterfaceOrientationLandscapeLeft || orientation == UIInterfaceOrientationLandscapeRight) {
titleImageView.center = CGPointMake(235.0f, 42.0f);
subtitleImageView.center = CGPointMake(355.0f, 70.0f);
...
}
else if (orientation == UIInterfaceOrientationPortrait || orientation == UIInterfaceOrientationPortraitUpsideDown) {
titleImageView.center = CGPointMake(160.0f, 52.0f);
subtitleImageView.center = CGPointMake(275.0f, 80.0f);
...
}
}
To keep this clean you could easily compartmentalize the view adjustments/reloading/etc. with methods called from inside the single if-else conditional.
It really depends on what it is you are laying out.
If you look at the Apple Settings application, you can see that they use table views for the layout, with custom cells for most rows. With that, you can allow a simple interface to rotate pretty cheaply by just filling the width of the cells. This even applies to things like Mail, where there are edit text cells in each row. And tables can easily be all transparent, with only buttons or labels visible, so they do not look like tables.
You can get a lot of milage out of the autoresizingMask of every UIView. If you have one or more items that can have a flexible height, then you can usually get an interface layout that looks good in either orientation. Depending on how it looks, sometimes you can just pin everything to the top.
In rare cases, if all the interface elements fit in a square, you can just rotate them in place.
There are two times when you must explicitly handle orientation changes. One is when a view moves from beside to below another on rotation. The other is when you have different images for each orientation, for example if you always want to be full width.
There are sometimes ways to work around both of these. You might use stretchable images or limit yourself to one view per line. Or you might lock out orientation for certain views.
If you must change the layout of views, there is an explicit layoutSubviews method. You should try to handle all you conditional layout in this one method. It is only called when the view bounds change, for example on rotation or if you have made room for the keyboard. Make a custom view for each view hierarchy that needs to respond to rotation, and layout the subviews from there.
The iPhone SDK is built around having an MVC architecture, so in theory if you keep all your logic (model) separated from your UI (view) then you will only have to worry about the UI in one spot: your view controllers. For those, you could have a separate view controller for each orientation, each of which would then just be loaded with one if/else to choose which view controller to load.
The same idea holds for iPhone / iPad support, where you can load another view controller which can handle larger displays.
Refer the following link:
http://mustafashaik.wordpress.com/2010/11/17/handling-orientations-in-ipad/
I can't vouch for this code, and in all honesty the above willRotateToInterfaceOrientation works great. Here's another take on it with FBDialog.m from Facebook for iphone / ipad. (albeit, I think this was for a webview)
here's the gist
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(deviceOrientationDidChange:)
name:#"UIDeviceOrientationDidChangeNotification" object:nil];
- (void)deviceOrientationDidChange:(void*)object {
UIDeviceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;
if ([self shouldRotateToOrientation:orientation]) {
CGFloat duration = [UIApplication sharedApplication].statusBarOrientationAnimationDuration;
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:duration];
[self sizeToFitOrientation:YES];
[UIView commitAnimations];
}
}
-(CGAffineTransform)transformForOrientation {
UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;
if (orientation == UIInterfaceOrientationLandscapeLeft) {
return CGAffineTransformMakeRotation(M_PI*1.5);
} else if (orientation == UIInterfaceOrientationLandscapeRight) {
return CGAffineTransformMakeRotation(M_PI/2);
} else if (orientation == UIInterfaceOrientationPortraitUpsideDown) {
return CGAffineTransformMakeRotation(-M_PI);
} else {
return CGAffineTransformIdentity;
}
}
- (void)sizeToFitOrientation:(BOOL)transform {
if (transform) {
self.transform = CGAffineTransformIdentity;
}
CGRect frame = [UIScreen mainScreen].applicationFrame;
CGPoint center = CGPointMake(
frame.origin.x + ceil(frame.size.width/2),
frame.origin.y + ceil(frame.size.height/2));
CGFloat scale_factor = 1.0f;
if (FBIsDeviceIPad()) {
// On the iPad the dialog's dimensions should only be 60% of the screen's
scale_factor = 0.6f;
}
CGFloat width = floor(scale_factor * frame.size.width) - kPadding * 2;
CGFloat height = floor(scale_factor * frame.size.height) - kPadding * 2;
_orientation = [UIApplication sharedApplication].statusBarOrientation;
if (UIInterfaceOrientationIsLandscape(_orientation)) {
self.frame = CGRectMake(kPadding, kPadding, height, width);
} else {
self.frame = CGRectMake(kPadding, kPadding, width, height);
}
self.center = center;
if (transform) {
self.transform = [self transformForOrientation];
}
}
In your question, you wrote:
I can just imagine so many issues with spaghetti code/thousands of "if" checks all over the place, that it would drive me nuts to make one small change to the UI arrangement.
One way to dodge this is to make a view hierarchy that splits the handling of iPhone/iPad specific changes from the very beginning. You'd only have to set which view is initially loaded for each device. Then you create a viewcontroller like you normally do, but you also subclass the viewcontroller you've created. One subclass for each device. That's where you can put the device specific code, like orientation handling. Like this:
MyViewController.h // Code that is used on both devices
MyViewController_iPhone.h // iPhone specific code, like orientation handling
MyViewController_iPad.h // iPad specific code, like orientation handling
If you are interested in this approach, I'd suggest that you read this article. It explains it in a very nice way.
One of the things the article mentions, is this:
--start of quote--
The beauty of this pattern is we don’t have to litter our code with crap that looks like this:
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
// The device is an iPad running iPhone 3.2 or later.
// set up the iPad-specific view
} else {
// The device is an iPhone or iPod touch.
// set up the iPhone/iPod Touch view
}
---end of quote--
I hope that helps. Good luck!
I've noticed that I'm getting very intermittent orientation on my device & the simulator.
I have a modal view controller that I present, and that is the only thing in my app which supports rotation.
If I launch the app in portrait without moving the device, open the modal VC and then rotate the device, it usually works. However sometimes if I open the app holding the device in landscape, then rotate to portrait, launch the VC and then rotate the device, no rotation occurs. It seems very intermittent. Sometimes if I launch the app in portrait mode and then open the VC and rotate the device, nothing happens, and until I quit and relaunch it no orientation occurs in the app.
It's strange because 50% of the time it works! Whenever I launch it through Xcode and set breakpoints in shouldAutorotateToInterfaceOrientation it always works!
Anyone ever had this or know what's going on?
Since as you mentioned "intermittent", i would say it has something to do with what are you doing after the rotation.
To find the bug, i suggest removing any code after the rotation happens. Comment out any network activities or OpenGL operations. Could also help to close XCode and reopen it.
If nothing helps, i would make a new project and start moving the files one by one and test.
I've had similar challenges getting autorotation to work properly for view controllers whose parent view controllers don't autorotate, although most of my experience has related to wrangling UINavigationController as opposed to modal view controllers. Still, I'd recommend trying the following:
Call presentModalViewController: on the top level view controller in your hierarchy rather than a deeper viewController.
If that doesn't solve it, try subclassing your top level view controller, and overriding its shouldAutorotateToInterfaceOrientation: to look something like this:
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
if (self.modalViewController) {
return [self.modalViewController shouldAutorotateToInterfaceOrientation:interfaceOrientation];
}
return [super shouldAutorotateToInterfaceOrientation:interfaceOrientation];
}
Does calling
[[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
when you show your rotation-aware view help? (and possibly turning it off again when you dismiss it?)
The other thing I would look for is suspicious calls to [UIWindow makeKeyWindow] or [UIResponder becomeFirstResponder].
I'd also sign up for UIDeviceOrientationDidChangeNotification events and make sure that the Modal view got a call to [UIViewController shouldAutorotateToInterfaceOrientation:] for each event you receive.
I've finally discovered what the problem was!
It turns out that only the very first UIView you add to your UIWindow will get asked whether or not to rotate. Any subsequent views don't receive this message. My app was using another view to animate away from the Default.png that is displayed on launch, and this was added to the window first!
Even if you try to launch your application in landscape, your phone will launch it in portrait and then go into landscape depending in which position your phone is.
I don't know what code you are using to accomplish this. Below is one which is taken from Apple code snippets. See if this can help.
- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)
interfaceOrientation duration:(NSTimeInterval)duration {
if (interfaceOrientation == UIInterfaceOrientationPortrait)
{
self.view = self.portrait;
self.view.transform = CGAffineTransformIdentity;
self.view.transform = CGAffineTransformMakeRotation(degreesToRadian(0));
self.view.bounds = CGRectMake(0.0, 0.0, 300.0, 480.0);
}
else if (interfaceOrientation == UIInterfaceOrientationLandscapeLeft)
{
self.view = self.landscape;
self.view.transform = CGAffineTransformIdentity;
self.view.transform = CGAffineTransformMakeRotation(degreesToRadian(-90));
self.view.bounds = CGRectMake(0.0, 0.0, 460.0, 320.0);
}
else if (interfaceOrientation == UIInterfaceOrientationPortraitUpsideDown)
{
self.view = self.portrait;
self.view.transform = CGAffineTransformIdentity;
self.view.transform = CGAffineTransformMakeRotation(degreesToRadian(180));
self.view.bounds = CGRectMake(0.0, 0.0, 300.0, 480.0);
}
else if (interfaceOrientation == UIInterfaceOrientationLandscapeRight)
{
self.view = self.landscape;
self.view.transform = CGAffineTransformIdentity;
self.view.transform =
CGAffineTransformMakeRotation(degreesToRadian(90));
self.view.bounds = CGRectMake(0.0, 0.0, 460.0, 320.0);
}
}