Removing views from UIScrollView - iphone

Using the PhotoScroller example from Apple, to reuse the memory allocated for views, I cannot get the memory released once the retain count hits 0. Here my code for a better understanding:
This piece is an extract from PhotoScroller
PhotoViewController.m
- (void)configurePage:(ImageScrollView *)page forIndex:(NSUInteger)index
{
page.index = index;
page.frame = [self frameForPageAtIndex:index];
[page displayPage:index];
}
ImageScrollView.h
#interface ImageScrollView : UIView
{
UIViewController *vc;
NSUInteger index;
}
#property (assign) NSUInteger index;
- (void)displayPage:(int)indice;
#end
ImageScrollView.m
- (void)dealloc
{
[vc release];
[super dealloc];
}
- (void)displayPage:(int)indice
{
//remove previous view
[vc.view removeFromSuperview];
[vc release];
vc = nil;
//NSLog(#"vc retain %i", [vc retainCount]);
// make a new viewController for the new page
Class clss = NSClassFromString([NSString stringWithFormat:#"page_0%i", indice + 1]);
vc = [[clss alloc] initWithNibName:[NSString stringWithFormat:#"page_0%i", indice + 1] bundle:nil];
[self addSubview:vc.view];
}
The classes "page_0x" are UIViewControllers. So far have nothing but a UIImageView on the XIB.
An example of page_01:
#implementation page_01
-(BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
// Overriden to allow any orientation.
return YES;
}
- (void)didReceiveMemoryWarning {
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
- (void)viewDidUnload {
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (void)dealloc {
[super dealloc];
}
#end
Memory peaks to 148 MB on device. Gives me a memory warning Level 1, then releases some memory. Goes down to 95 MB. Keeps going up and down.

Perhaps your page_0x view controllers are getting freed, but something they've created isn't. Some things to check:
Set a breakpoint in the dealloc method of your page_0x view controllers. Is it getting called?
Check all the IBOutlets and other instance variables of your page_0x view controllers. Are they all being released properly in their class's dealloc method?
Run Build & Analyze. Does it turn up anything?
Try running the Leaks Instrument. It can tell you what kind of objects are actually leaking.
(EDIT) Grasping at straws now. You don't have NSZombieEnabled turned on, do you?
(EDIT 2) You say you're throwing a .png on it. What happens if you remove that .png?
If you're running in the simulator, try it on the device. (See this question.)

Related

UIImagePickerControllerCameraDeviceFront works every other time

This question is very similar to an existing question asked here UIImagePickerControllerCameraDeviceFront only works every other time I tried the solution presented but it didn't work for me
I have a simplest of a project with two view controllers. In the blue one I am displaying a small UIView with a UIImagePickerController in it. NOTE: I am displaying front facing camera when app is launched.
I hit the next button and go to orange view controller and when I hit the back button and come back to blue view controller the UIImagePickerController flips from Front to rear. I guess the reason is that it thinks its busy and moves to the rear cam. If I keep moving back and forth between the view controllers the camera keeps flipping front, back, front, back, front, back...
Here is my code and screenshots, what am I doing wrong?
In my *.h
#import <UIKit/UIKit.h>
#interface v1ViewController : UIViewController <UIImagePickerControllerDelegate>
{
UIImagePickerController *picpicker;
UIView *controllerView;
}
#property (nonatomic, retain) UIImagePickerController *picpicker;
#property (nonatomic, retain) UIView *controllerView;
#end
In my *.m file (This code is only used when blue colored view controller is displayed)
#import "v1ViewController.h"
#import <MobileCoreServices/UTCoreTypes.h>
#implementation v1ViewController
#synthesize picpicker;
#synthesize controllerView;
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
#pragma mark - View lifecycle
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
}
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
picpicker = [[UIImagePickerController alloc] init];
picpicker.delegate = self;
picpicker.mediaTypes = [NSArray arrayWithObjects:(NSString *)kUTTypeImage, nil];
picpicker.sourceType = UIImagePickerControllerSourceTypeCamera;
picpicker.cameraDevice = UIImagePickerControllerCameraDeviceFront;
picpicker.cameraCaptureMode = UIImagePickerControllerCameraCaptureModePhoto;
picpicker.showsCameraControls = NO;
picpicker.navigationBarHidden = NO;
picpicker.wantsFullScreenLayout = NO;
controllerView = picpicker.view;
[controllerView setFrame:CGRectMake(35, 31, 250, 250)];
controllerView.alpha = 0.0;
controllerView.transform = CGAffineTransformMakeScale(1.0, 1.0);
[self.view addSubview:controllerView];
[UIView animateWithDuration:0.3
delay:0.0
options:UIViewAnimationOptionCurveLinear
animations:^{
controllerView.alpha = 1.0;
}
completion:nil
];
}
- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
[picpicker dismissModalViewControllerAnimated:YES];
}
- (void)viewDidDisappear:(BOOL)animated
{
[super viewDidDisappear:animated];
[picpicker dismissModalViewControllerAnimated:YES];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
} else {
return YES;
}
}
#end
You are dismissing the controller in both the viewDidDisappear and viewWillDisappear methods.
That could be the cause of your problem.
Although I do not have a device with a camera available right now to verify this, it seems that you're not dismissing the pickerview controller correctly. The documentation states that you should call dismissModalViewControllerAnimated: on the parent controller in order to dismiss the picker (though, calls to presented controllers will propagate to presenters - so this is not the problem), but in your case you're not displaying the controller modally in the first place so it will not work.
What I would try in this case is to release the picker instead (if not under ARC) and set it to nil (instead of calling [picpicker dismissModalViewControllerAnimated:YES];).
PS. In fact, it seems that there is a bigger problem with your design. Since each button is set to present the other party modally you are not dismissing any of the controllers ever. The controllers just keep stacking on each other. You should either consider to embed them in a navigation controller and have it handle the hierarchy or just set dismissModalViewControllerAnimated: (dismissViewControllerAnimated:completion: on iOS5+) as the action of the second controller's button instead of a modal segue.
This is a very simple issue. I don't know why this happens exactly, but it seems that UIImagePickerController was designed to recreated each time it's needed instead of keeping any reference to it, which seems logical if you think about it. Basically, you need to recreate and reconfigure your picker each time. Below I've pasted some code to give an image of what I mean.
Simple solution:
- (UIImagePickerController *)loadImagePicker {
UIImagePickerController *picpicker = [[UIImagePickerController alloc] init];
picpicker.delegate = self;
picpicker.mediaTypes = [NSArray arrayWithObjects:(NSString *)kUTTypeImage, nil];
picpicker.sourceType = UIImagePickerControllerSourceTypeCamera;
picpicker.cameraDevice = UIImagePickerControllerCameraDeviceFront;
picpicker.cameraCaptureMode = UIImagePickerControllerCameraCaptureModePhoto;
picpicker.showsCameraControls = NO;
picpicker.navigationBarHidden = NO;
picpicker.wantsFullScreenLayout = NO;
return picpicker;
}
and in:
-(void)viewWillAppear:(BOOL)animated{
if(!self.picpicker){
self.picpicker = [self loadImagePicker];
[self.view addSubview: self.picpicker];
}
}
-(void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
[self.picpicker removeFromSuperview];
self.picpicker = nil;
}

objective-c memory management clarification

I am trying to make a simple iphone app and I have been playing around with features and recently, delegates. I am just confused with regards to memory management because apparently "good code" makes my app crash with exc_bad_access.
I have an object with two data members and implementation empty for now.
#implementation semester: NSObject{
NSInteger ID;
NSString *name;
}
then my delegate method:
- (void) receiveSemester:(semester *)newSemester {
[test setText:newSemester.name];
}
and a view that is used as a form which has:
#interface addSemesterController : UIViewController {
id<ModalViewDelegate> delegate;
UITextField *txtName;
UILabel *prompt;
UIButton *ok;
UIButton *cancel;
}
all objects are made properties and synthesized in the application file. Here is the method that used the delegate:
- (IBAction) okClick:(id)sender{
// create semester object and return it
semester *created = [[semester alloc] init];
created.name = txtName.text;
[delegate receiveSemester:created];
[self dismissModalViewControllerAnimated:YES];
}
And my dealloc method looks like this:
- (void)dealloc {
/*
[txtName dealloc];
[prompt dealloc];
[ok dealloc];
[cancel dealloc];
*/
[super dealloc];
}
With the deallocs of the objects contained in the form commented out, my app runs ok. However, when I uncomment them, I receive the exc_bad_access error in my delegate protocol:
// in main view controller
- (void) receiveSemester:(semester *)newSemester {
[test setText:newSemester.name];
// test is a UILabel
}
I tried the zombie method and it says that the label calls a released object. I am not releasing my semester object in the "form" controller, and even if I was the delegate function is called before deallocating the view.
Clearly I should not be releasing the objects in the dealloc method, I am just unclear in the why I shouldn't.
Again, thanks in advance for the help.
Use release to release the variables instead of calling dealloc on variables, due to this you are having issue -
- (void)dealloc {
[txtName release];
[prompt release];
[ok release];
[cancel release];
[super dealloc];
}
try writing
[txtName release];
[prompt release];
[ok release];
[cancel release];
instead of dealloc and these objects will be deallocated properly

Odd Scrolling Issue ( UIScrollView )

I have searched endlessly to no avail on this, hopefully someone can help!
I have a UIScrollView on the left half of a UIView which loads in custom cells/subviews. The UIView is part of a UINavigation stack, and it's also loaded into a tab on a TabBar.
What happens is, if I start the app and begin scrolling right away it's very smooth. However if I start the app and wait 5-10 seconds, the UIScrollView is VERY laggy and choppy (and it stays like that). I would think that it would be a memory leak or something, but I can't seem to find anything.
Included is the code of the view where I'm loading the custom cells/subviews into the UIScrollView. There isn't any custom code in the cell subview. Oh, and there's only about 8-10 items: each item has a small (150x150) image, and 3 text fields - all opaque.
#import "ProductListViewController.h"
#import "ProductListLeftItemViewController.h"
#implementation ProductListViewController
#synthesize listScroll;
- (void)viewDidLoad {
NSBundle *bundle = [NSBundle mainBundle];
NSString *path = [bundle pathForResource:#"Products" ofType:#"plist"];
NSArray *products = [[NSArray alloc] initWithContentsOfFile:path];
//
int numProducts;
numProducts = [products count];
[listScroll setContentSize:CGSizeMake(500, (numProducts * 111))];
for (int i = 0; i < numProducts; i++) {
ProductListLeftItemViewController *cellItem = [[ProductListLeftItemViewController alloc] initWithNibName:#"ProductListLeftItem" bundle:nil];
cellItem.view.frame = CGRectMake(0, (i*111), 500, 111);
[self.listScroll addSubview:cellItem.view];
cellItem = nil;
[cellItem release];
}
[products release];
[super viewDidLoad];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
return (interfaceOrientation == UIInterfaceOrientationLandscapeRight);
}
- (void)didReceiveMemoryWarning {
// Releases the view if it doesn't have a superview.
NSLog(#"Memory warning, ProductListViewController");
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
- (void)viewDidUnload {
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (void)dealloc {
[listScroll release];
[super dealloc];
}
#end
And as requested, the ProductListLeftItemViewController code:
#import "ProductListLeftItemViewController.h"
#implementation ProductListLeftItemViewController
#synthesize titleTxt, descriptionTxt, modelTxt, productThumb;
// The designated initializer. Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
/*
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization.
}
return self;
}
*/
/*
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
}
*/
/*
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
[super viewDidLoad];
}
*/
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
return YES;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
- (void)viewDidUnload {
titleTxt = nil;
descriptionTxt = nil;
modelTxt = nil;
productThumb = nil;
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (void)dealloc {
[titleTxt release];
[descriptionTxt release];
[modelTxt release];
[productThumb release];
[super dealloc];
}
#end
For anyone that has this problem in the future, once I started testing things on the actual device, everything worked perfectly smooth. Maybe it was just something quirky with the simulator? I'll consider this resolved, even though I'm still going to look into it a little further.

Why does my UITableView change from UITableViewStyleGrouped to UITableViewStylePlain

My application has a view controller that extends UITableViewController. The initialization method looks like this:
- (id)initWithCoder:(NSCoder*)coder {
if (self = [super initWithCoder:coder]) {
self.tableView = [[UITableView alloc] initWithFrame:self.tableView.frame
style:UITableViewStyleGrouped];
}
return self;
}
When the view is initially loaded, it's displayed as UITableViewStyleGrouped. However, if my app ever receives a low memory warning, the above view changes to UITableViewStylePlain. There is no associated xib file with the View/Controller. The viewDidUnload and didReceiveMemoryWarning methods are straightforward:
- (void)didReceiveMemoryWarning {
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
- (void)viewDidUnload {
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
My question is, why does the table style change when I receive a memory warning?
It happens on the device and on the simulator. The device is a 3G iphone running OS 3.1.3, the simulator is running OS 3.1
In your initialization, you call [super initWithCoder:coder]. It would probably be better to override the designated initializer for UITableViewController, which is -initWithStyle:. What's probably happening is that when you create the table view controller by calling [super init…], it's being created with its tableView property already being set; that is, it's creating the table view on initialization. That's why your call to self.tableView.frame works—that shouldn't work if the value of self.tableView is nil. Here's a better implementation:
- (id)initWithCoder:(NSCoder*)coder {
if (self = [super initWithStyle:UITableViewStyleGrouped]) {
}
return self;
}

Memory Crash due to [super dealloc] of uiview controller

I am having a uiviewcontroller instance and when I am releasing it the dealloc method of it is called.
I have released some objects in dealloc method of that uiviewcontroller.
If I comment [super dealloc] the app is working fine but if don't it is crashing.
I think there is no problem with the releases that I am doing in that method, but if I do [super dealloc] it is crashing.
Can any one help me out with this?
Hard to tell from your post without more information, but does your dealloc method look like this?
- (void)dealloc {
[super dealloc];
self.someProperty = nil;
}
Because if it does, you're calling a setter method on a deallocated instance. You should always call [super dealloc] last:
- (void)dealloc {
self.someProperty = nil;
[super dealloc];
}
Not sure if that helps. Try posting what your dealloc method looks like if not. Hard to troubleshoot in the dark.
It's not possible to help you without more information. The code you described is perfectly fine. The problem is in some other part of your app.
You probably access the view controller after releasing it, so the problem is not the [super dealloc] but any other place in you application that accesses the view controller.
Maybe you are releasing the controller in the wrong place. That could be why your [super dealloc] in your ViewController.m is crashing
You shouldn't called [viewController release] until you want that controller to die. For example, if you have an application with just a viewcontroller you must not release it until the application ends. This is because that controller needs to stay alive all the time to control the view. If you have in your ApplicationDelegate something like this, it will crash:
- (void)applicationDidFinishLaunching:(UIApplication *)application {
UIViewController *controller = [[UIViewController alloc] init];
[window addSubview:controller.view];
[controller release]; //this will crash
}
Instead of that you should place your viewcontroller in the header file (.h) and release it in the dealloc method:
- (void)dealloc {
[controller release];
[window release];
[super dealloc];
}
I hope this helps.