I have this example, and I would like to make my_Picture an instance variable in order to use removeFromView. Any Ideas? I got all kinds of warnings and errors trying different approaches. Thank you in advance
- (void) viewDidLoad
{
UIImageView *my_Picture = [[UIImageView alloc] initWithImage: myImageRef];
[self.view addSubview:my_Picture];
[my_Picture release];
[super viewDidLoad];
}
To make it an instance variable you would store the value in your class instead of as a temporary variable. You will also release it when your class is destroyed instead of after adding it as a subview.
E.g.
// header file (.h)
#interface MyController : UIViewController
{
UIImageView* myPicture;
}
#end
// source file (.m)
- (void) viewDidLoad
{
myPicture = [[UIImageView alloc] initWithImage: myImageRef];
[self.view addSubview:myPicture];
[super viewDidLoad];
}
- (void) dealloc
{
[myPicture release];
[super dealloc];
}
Related
I want to add GestureRecognizer on an imageView and use a block in the clickAction.
But when I run it, I get this error in the block:
Thread 1:EXC_BAD_ACCESS(code=1,address=0x0)
#import "blockImage.h"
#implementation blockImage
-(instancetype)init{
if (self = [super init]) {
self = [[blockImage alloc]initWithFrame:CGRectMake(100, 100, 100, 100)];
self.tag = 10;
self.backgroundColor = [UIColor redColor];
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:#selector(tapActionWithBolck:)];
[self addGestureRecognizer:tap];
}
return self;
}
-(void)tapActionWithBolck:(void(^)(NSInteger idx))completion{
completion(10);
}
#end
and
#import "ViewController.h"
#import "blockImage.h"
#interface ViewController ()
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
blockImage *img = [[blockImage alloc] init];
[self.view addSubview:img];
}
#end
You can not use method like this with UITapGestureRecognizer
-(void)tapActionWithBolck:(void(^)(NSInteger idx))completion;
it should be like that
-(void)tapAction:(UIGestureRecognizer *)sender;
or
-(void)tapAction;
If you want to use block on tap, you should keep it in variable (in init for example) and than call it in method. But keep in mind about retain cycles.
I have made a custom delegate:
Example.h:
#protocol DismissExamplePopoverDelegate
- (void) dismissExamplePopover;
- (int) getUserID;
#end
#interface Example : UIViewController{
id<DismissExamplePopoverDelegate> delegate;
}
#property (nonatomic, assign) id<DismissExamplePopoverDelegate> delegate;
It is called in Example.m like follows:
[[self delegate] getUserID];
In my maincontroller.h:
#import "Example.h"
#interface MainScreen : UIViewController<DismissExamplePopoverDelegate>
maincontroller.m:
-(int) getUserID
{
return 100;
}
the view Example is called by the following method:
ExampleController = [[Example alloc] initWithNibName:#"Example" bundle:nil];
ExamplePopoverController = [[UIPopoverController alloc] initWithContentViewController:ExampleController];
[ExampleController setDelegate:self];
ExamplePopoverController.popoverContentSize = CGSizeMake(600, 480);
if ([ExamplePopoverController isPopoverVisible]) {
[ExamplePopoverController dismissPopoverAnimated:YES];
} else {
CGRect popRect = CGRectMake((self.EditExampleSelectAddButtonProperty.frame.origin.x),
(self.EditExampleSelectAddButtonProperty.frame.origin.y),
(self.ExampleSelectAddButtonProperty.frame.size.width),
(self.ExampleSelectAddButtonProperty.frame.size.height));
[ExamplePopoverController presentPopoverFromRect:popRect inView:self.view permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
}
If I place [[self delegate] getUserID] in any function other than viewdidload it works perfectly: returns 100; in viewdidload it returns 0.
What i want to achieve is a delegate to be called automatically when the popover loads. Is viewdidload the best place for it, or is there somewhere else
A couple of people have said this, but haven't been clear enough about the solution.
Instead of doing this:
ExampleController = [[Example alloc] initWithNibName:#"Example" bundle:nil];
ExamplePopoverController = [[UIPopoverController alloc] initWithContentViewController:ExampleController];
[ExampleController setDelegate:self];
Do this:
ExampleController = [[Example alloc] initWithNibName:#"Example" bundle:nil];
[ExampleController setDelegate:self];
ExamplePopoverController = [[UIPopoverController alloc] initWithContentViewController:ExampleController];
What's happening is that -[UIPopoverController initWithContentViewController:] uses its contentViewController's view, causing -[Example viewDidLoad] to be called. Since you haven't yet set the delegate at that point, the delegate is nil, and attempting to call any method on nil returns nil, 0, or 0.0.
Make sure you're actually assigning the delegate property to MainController. For instance, wherever you've initialized Example, you need to set the delegate property:
Example *example = [[Example alloc] init];
example.delegate = self; // Use this if you're initializing Example in MainController
If you're not initializing Example in MainController, instead of "self" use the MainController instance.
In Example.m you need to add line:
[self setDelegate:delegate];
Also, you need to #synthesize delegate;
Hope it help)
It's stepping into the ViewDidLoad of the main view controller, and hitting the line calling get all tweets, but I put a breakpoint in the getAllTweets of both the base and derived to see if it just wasn't hitting the derived like I expected.
#implementation WWMainViewControllerTests {
// system under test
WWMainViewController *viewController;
// dependencies
UITableView *tableViewForTests;
WWTweetServiceMock *tweetServiceMock;
}
- (void)setUp {
tweetServiceMock = [[WWTweetServiceMock alloc] init];
viewController = [[WWMainViewController alloc] init];
viewController.tweetService = tweetServiceMock;
tableViewForTests = [[UITableView alloc] init];
viewController.mainTableView = tableViewForTests;
tableViewForTests.dataSource = viewController;
tableViewForTests.delegate = viewController;
}
- (void)test_ViewLoadedShouldCallServiceLayer_GetAllTweets {
[viewController loadView];
STAssertTrue(tweetServiceMock.getAllTweetsCalled, #"Should call getAllTweets on tweetService dependency");
}
- (void)tearDown {
tableViewForTests = nil;
viewController = nil;
tweetServiceMock = nil;
}
The base tweet service:
#implementation WWTweetService {
NSMutableArray *tweetsToReturn;
}
- (id)init {
if (self = [super init]) {
tweetsToReturn = [[NSMutableArray alloc] init];
}
return self;
}
- (NSArray *)getAllTweets {
NSLog(#"here in the base of get all tweets");
return tweetsToReturn;
}
#end
The Mock tweet service:
#interface WWTweetServiceMock : WWTweetService
#property BOOL getAllTweetsCalled;
#end
#implementation WWTweetServiceMock
#synthesize getAllTweetsCalled;
- (id)init {
if (self = [super init]) {
getAllTweetsCalled = NO;
}
return self;
}
- (NSArray *)getAllTweets {
NSLog(#"here in the mock class.");
getAllTweetsCalled = YES;
return [NSArray array];
}
The main view controller under test:
#implementation WWMainViewController
#synthesize mainTableView = _mainTableView;
#synthesize tweetService;
NSArray *allTweets;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
allTweets = [tweetService getAllTweets];
NSLog(#"was here in view controller");
}
- (void)viewDidUnload
{
[self setMainTableView:nil];
[super viewDidUnload];
// Release any retained subviews of the main view.
}
Since you're able to break in the debugger in viewDidLoad, what's the value of the tweetService ivar? If it's nil, the getAllTweets message will just be a no op. Maybe the ivar isn't being set properly or overridden somewhere else.
You should probably use the property to access the tweetService (call self.tweetService) rather than its underlying ivar. You should only ever access the ivar directly in getters, setters, and init (also dealloc if aren't using ARC for some crazy reason).
You also should not call loadView yourself, rather just access the view property of the view controller. That will kick off the loading process and call viewDidLoad.
Also, if you're doing a lot of mocking, I highly recommend OCMock.
I want to package some UIViews suchs as UIButton, UIImageView in a single UIView.
When I try to display that view, it is not showing up on my RootViewController:
Here is the code of my UIView subclass :
#import "Hover.h"
#implementation Hover
- (id)init{
self = [super init];
if (self) {
// Initialization code
UIImage *hover = [UIImage imageNamed:#"Hover.png"];
UIImageView *imageView = [[UIImageView alloc] init];
imageView.image = hover;
imageView.frame = CGRectMake(0, 0, hover.size.width, hover.size.height);
imageView.alpha = 0.75;
[self addSubview:imageView];
[imageView release];
}
return self;
}
And here is the RootViewController class:
- (void)viewDidLoad
{
Hover *hover = [[Hover alloc] init];
[self.navigationController.view addSubview:hover];
[hover release];
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
The "hover view" is not displayed! However, when I add a single UIImageView to my RootViewController, it works!
In order for your view to display, you should override the -(id)initWithFrame:(CGRect)frame;, instead of writing a custom initializer.
Try this way :
-(id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if(self) {
// do init here...
}
return self;
}
Also, in the -(void)viewDidLoad; method, first send [super viewDidLoad];, and then alloc/init the view.
- (void)viewDidLoad
{
[super viewDidLoad];
Hover *hover = [[Hover alloc] init];
[self.navigationController.visibleViewController.view addSubview:hover];
[hover release];
// Do any additional setup after loading the view, typically from a nib.
}
Just a quick guess at a glance: If you're using a navigationcontroller, you should initWithRootViewController. You can't add a view to a navigationcontroller directly, Use push instead.
HTH
Marcus
I am trying to access properties of an object (person's firstName) which is stored in an array and assign it to labels in a seperate view Controller (SplitMethodViewController). The name value is successfully assigned here. Code snippet as below:
In the initial view controller (before displaying the modal view controller containing the UILabel):
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
int row = [indexPath row];
Person *thisPerson = (Person *)[self.personArray objectAtIndex:row];
SplitMethodViewController *smvc = [[SplitMethodViewController alloc]initWithNibName:nil bundle:nil];
smvc.nameLabel.text = [[NSString alloc] initWithFormat:#"%#", thisPerson.firstName];
//This lines returns the value I want, showing that assignment is working till this point
NSLog(#"The name label is %#", smvc.nameLabel.text);
[self presentModalViewController:smvc animated:YES];
[smvc release];
}
However, the values became blank when I check in the splitMethodViewController (checked in ViewDidLoad Method)
#interface SplitMethodViewController : UIViewController
{
UILabel *nameLabel;
}
#property (nonatomic, retain) IBOutlet UILabel *nameLabel;
#end
#implementation SplitMethodViewController
#synthesize nameLabel;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization.
self.nameLabel = [[UILabel alloc] init];
}
return self;
}
- (id)init
{
return [self initWithNibName:nil bundle:nil];
}
- (void)viewDidLoad
{
//name label returning nothing here.
NSLog(#"namelabel is %#",self.nameLabel.text);
[super viewDidLoad];
}
#end
I am sure I made some silly mistake somewhere. I have tried deleting all the outlets and labels and re-created just one name label and outlet. But I am still hitting this same issue.
Any help will be appreciated!
Did you actually allocate and instantiate the nameLabel and evenBillAmountLabel once you instantiate the SplitMethodViewController? In Objective-C messages (method calls) can be sent to nil (non-existant objects) without returning any errors, but also without any results.
Make sure the -init method on SplitMethodViewController looks somewhat like this:
// this is the designated initializer of most view controllers,
// do initialization here ...
- (id)initWithNibName:(NSString *)nibName bundle:(NSBundle *)nibBundle
{
self = [super initWithNibName:nibName bundle:nibBundle];
if (self)
{
nameLabel = [[UILabel alloc] init];
evenBillAmountLabel = [[UILabel alloc] init];
// add other stuff you need to initialize ...
}
return self;
}
- (id)init
{
// since we don't wanna re-implement allocation and instantiation for every
// initializer, we call the 'designated initializer' with some default values,
// in this case the default nibName and bundle are nil.
return [self initWithNibName:nil bundle:nil];
}
- (void)dealloc
{
[nameLabel release];
[evenBillAmountLabel release];
[super dealloc];
}
Be sure to read about designated initializers if this is new to you and if this was related to your issue. Here's a link to Apple's documentation on the subject.
If Wolfgang's answer doesn't solve it, be sure that your UILabel references in your SplitMethodViewController.xib file are wired up to the correct referencing outlet in your SplitMethodViewController.h file.