I want to navigate to another view. I have like a now playing button for my radio application. I would like the view to mentain its state... the view that I want to navigate to has a text field for url of the radion and a label for radio name. so how can I mentain the state of that view because right now when ever I try to navigate it navigates fine but the text field changes.. so what can I do to not change the text?
here is some code sorry about wierd names
if (self.bookDetailViewController_1 == nil)
{
iPhoneStreamingPlayerViewController *aBookDetail = [[iPhoneStreamingPlayerViewController alloc] initWithNibName:#"iPhoneStreamingPlayerView" bundle:nil];
self.bookDetailViewController_1= aBookDetail;
[aBookDetail release];
}
Music_appAppDelegate *delegate = [[UIApplication sharedApplication]delegate];
[delegate.booksNavController pushViewController:bookDetailViewController_1 animated:YES];
Singleton implementation
//.h
+ (className *)sharedInstance;
//.m
static className* sharedInstance = nil;
#implementation className
+ (className*)sharedInstance {
if (!sharedInstance) {
sharedInstance = [[super allocWithZone:NULL] init];
}
return sharedInstance;
}
+ (id)allocWithZone:(NSZone *)zone {
return [[self sharedInstance] retain];
}
- (id)copyWithZone:(NSZone *)zone {
return self;
}
- (id)retain {
return self;
}
- (NSUInteger)retainCount {
return NSUIntegerMax;
}
- (void)release { }
- (id)autorelease {
return self;
}
#end
Related
I'm trying to subclass NSTokenField to intercept some of the keyboard events. I wrote subclasses for NSTokenField, NSTokenFieldCell and NSTextView. In the NSTokenField subclass I swap the regular cell with my custom cell and in the custom cell I override -(NSTextView*)fieldEditorForView:(NSView *)aControlView to provide my textview as a custom field editor. All the initialisation methods are called as expected but for some reason my custom token field is not drawn.
Here is the code for the NSTokenField subclass:
#synthesize fieldEditor = _fieldEditor;
-(JSTextView *)fieldEditor
{
if (!_fieldEditor) {
_fieldEditor = [[JSTextView alloc] init];
[_fieldEditor setFieldEditor:YES];
}
return _fieldEditor;
}
- (void)awakeFromNib {
JSTokenFieldCell *newCell = [[JSTokenFieldCell alloc] init];
[self setCell:newCell];
}
+ (Class) cellClass
{
return [JSTokenFieldCell class];
}
- (id)initWithFrame:(NSRect)frameRect
{
self = [super initWithFrame:frameRect];
if (self) {
JSTokenFieldCell *newCell = [[JSTokenFieldCell alloc] init];
[self setCell:newCell];
}
return self;
}
-(id)initWithCoder:(NSCoder *)aDecoder
{
self = [super initWithCoder:aDecoder];
if (self) {
JSTokenFieldCell *newCell = [[JSTokenFieldCell alloc] initWithCoder:aDecoder];
[self setCell:newCell];
}
return self;
}
And here is the code for the subclass of NSTokenFieldCell:
-(NSTextView*)fieldEditorForView:(NSView *)aControlView
{
if ([aControlView isKindOfClass:[JSTokenField class]]) {
JSTokenField *tokenField = (JSTokenField *)aControlView;
return tokenField.fieldEditor;
}
return nil;
}
- (id)initWithCoder:(NSCoder *)decoder
{
return [super initWithCoder:decoder];
}
- (id)initTextCell:(NSString *)aString
{
return [super initTextCell:aString];
}
- (id)initImageCell:(NSImage *)anImage
{
return [super initImageCell:anImage];
}
Addition
After further digging I found this post which says that the only way to have an NSTokenField with a custom text view is by overriding private methods. Is it true? If so, is there any other way I can intercept keyboard events without subclassing NSTextView?
I created a Singleton class named DataManager. I've set up some caching. However, when attempting to call the cache instance methods from within another instance method of DataManager, I'm getting EXC_BAD_ACCESS error on the line:
NSMutableArray *stops = [[DataManager sharedInstance] getCacheForKey:#"stops"];
DataManager.h
#interface DataManager : NSObject {
FMDatabase *db;
NSMutableDictionary *cache;
}
+ (DataManager *)sharedInstance;
// ... more methods
- (id)getCacheForKey:(NSString *)key;
- (void)setCacheForKey:(NSString *)key withValue:(id)value;
- (void)clearCache;
DataManager.m
- (NSArray *)getStops:(NSInteger)archived {
NSMutableArray *stops = [[DataManager sharedInstance] getCacheForKey:#"stops"];
if (stops != nil) {
NSLog(#"Stops: %#", stops);
return stops;
}
stops = [NSMutableArray array];
// set stops...
[[DataManager sharedInstance] setCacheForKey:#"stops" withValue:stops];
return stops;
}
It seems to occur when called from another view controller. That is the first view controller no error, second view controller, error.
This is my first attempt at a Singleton, so I'm sure I am making a simple mistake. But I am failing to see it myself.
Note: I've tried [self getCache...] with the same result.
UPDATE
Here is my Singleton implementation. Adapted from http://www.galloway.me.uk/tutorials/singleton-classes/
+ (DataManager *)sharedInstance {
#synchronized(self) {
if (!instance) {
instance = [[super allocWithZone:NULL] init];
}
}
return instance;
}
+ (id)allocWithZone:(NSZone *)zone {
return [[self sharedInstance] retain];
}
- (id)copyWithZone:(NSZone *)zone {
return self;
}
- (id)retain {
return self;
}
- (unsigned)retainCount {
return UINT_MAX;
}
- (oneway void)release {
// never release
}
- (id)autorelease {
return self;
}
- (id)init {
if (self = [super init]) {
if (db == nil){
BourbonAppDelegate *appDelegate = (BourbonAppDelegate *)[[UIApplication sharedApplication] delegate];
[appDelegate createEditableCopyOfDatabaseIfNeeded];
db = [[FMDatabase alloc] initWithPath:[appDelegate getDBPath]];
}
if (![db open]) {
NSAssert(0, #"Failed to open database.");
[db release];
return nil;
}
[db setTraceExecution:YES];
[db setLogsErrors:TRUE];
cache = [NSMutableDictionary dictionary];
NSLog(#"cache: %#", cache);
}
return self;
}
Your cache object is autoreleased, so it's no longer in memory when you try to access it.
Use [NSMutableDictionary alloc] init] instead of [NSMutableDictionary dictionary] to get an instance that is retained.
Not a direct answer to your question, which was already answered.
However I'd just like to point out that your singleton implementation is sub-optimal. #synchronized is very expensive, and you can avoid using it every time you access the singleton:
if (!instance) {
#synchronized(self) {
if (!instance) {
instance = [[super allocWithZone:NULL] init];
}
}
}
An even better way to initialize a singleton would be:
+ (DataManager *)sharedInstance {
static DataManager *instance;
static dispatch_once_t donce;
dispatch_once(&donce, ^{
instance = [[self alloc] init];
});
return instance;
}
Have a singleton class for BNRItemStore, but when I tried to call it, I get the above error which causes an ARC issue. Have commented out the error.
DetailViewController.m
#import "DetailViewController.h"
#import "BNRItem.h"
#import "BNRImageStore.h"
#import "BNRItemStore.h"
#implementation DetailViewController
#synthesize item;
-(id)initForNewItem:(BOOL)isNew
{
self = [super initWithNibName:#"DetailViewController" bundle:nil];
if(self){
if (isNew) {
UIBarButtonItem *doneItem = [[UIBarButtonItem alloc]
initWithBarButtonSystemItem:UIBarButtonSystemItemDone
target:self
action:#selector(save:)];
[[self navigationItem] setRightBarButtonItem:doneItem];
UIBarButtonItem *cancelItem = [[UIBarButtonItem alloc]
initWithBarButtonSystemItem:UIBarButtonSystemItemCancel
target:self
action:#selector(cancel:)];
[[self navigationItem] setLeftBarButtonItem:cancelItem];
}
}
return self;
}
-(id)initWithNibName:(NSString *)nibName bundle:(NSBundle *)bundle
{
#throw [NSException exceptionWithName:#"Wrong initializer"
reason:#"Use initForNewItem:"
userInfo:nil];
return nil;
}
-(void)viewDidLoad
{
[super viewDidLoad];
UIColor *clr = nil;
if ([[UIDevice currentDevice]userInterfaceIdiom]== UIUserInterfaceIdiomPad) {
clr = [UIColor colorWithRed:0.875 green:0.88 blue:0.91 alpha:1];
} else {
clr = [UIColor groupTableViewBackgroundColor];
}
[[self view]setBackgroundColor:clr];
}
- (void)viewDidUnload {
nameField = nil;
serialNumberField = nil;
valueField = nil;
dateLabel = nil;
imageView = nil;
[super viewDidUnload];
}
-(void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
[nameField setText:[item itemName]];
[serialNumberField setText:[item serialNumber]];
[valueField setText:[NSString stringWithFormat:#"%d", [item valueInDollars]]];
// Create a NSDateFormatter that will turn a date into a simple date string
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
[dateFormatter setTimeStyle:NSDateFormatterNoStyle];
// Use filtered NSDate object to set dateLabel contents
[dateLabel setText:[dateFormatter stringFromDate:[item dateCreated]]];
NSString *imageKey = [item imageKey];
if (imageKey) {
// Get image for image key from image store
UIImage *imageToDisplay = [[BNRImageStore sharedStore]imageForKey:imageKey];
// Use that image to put on the screen in imageview
[imageView setImage:imageToDisplay];
} else {
// Clear the imageview
[imageView setImage:nil];
}
}
-(void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
// Clear first responder
[[self view]endEditing:YES];
// "Save" changes to item
[item setItemName:[nameField text]];
[item setSerialNumber:[serialNumberField text]];
[item setValueInDollars:[[valueField text] intValue]];
}
-(BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)io
{
if ([[UIDevice currentDevice]userInterfaceIdiom]==UIUserInterfaceIdiomPad) {
return YES;
} else {
return (io==UIInterfaceOrientationPortrait);
}
}
-(void)setItem:(BNRItem *)i
{
item = i;
[[self navigationItem] setTitle:[item itemName]];
}
- (IBAction)takePicture:(id)sender {
if ([imagePickerPopover isPopoverVisible]) {
// If the popover is already up, get rid of it
[imagePickerPopover dismissPopoverAnimated:YES];
imagePickerPopover = nil;
return;
}
UIImagePickerController *imagePicker =
[[UIImagePickerController alloc]init];
// If our device has a camera, we want to take a picture, otherwise, we
// just pick from the photo library
if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
[imagePicker setSourceType:UIImagePickerControllerSourceTypeCamera];
} else {
[imagePicker setSourceType:UIImagePickerControllerSourceTypePhotoLibrary];
// This line of code will generate a warning right now, ignore it
[imagePicker setDelegate:self];
//Place image picker on the screen
// Check for iPad device before instantiating the popover controller
if ([[UIDevice currentDevice]userInterfaceIdiom]==UIUserInterfaceIdiomPad) {
// Create a new popover controller that will display the imagepicker
imagePickerPopover = [[UIPopoverController alloc]initWithContentViewController:imagePicker];
[imagePickerPopover setDelegate:self];
// Display the popover controller; sender
// is the camera bar button item
[imagePickerPopover presentPopoverFromBarButtonItem:sender permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
} else {
[self presentViewController:imagePicker animated:YES completion:nil];
}
}
}
-(void)popoverControllerDidDismissPopover:(UIPopoverController *)popoverController
{
NSLog(#"User dismissed popover");
imagePickerPopover = nil;
}
- (IBAction)backgroundTapped:(id)sender {
[[self view]endEditing:YES];
}
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
NSString *oldKey = [item imageKey];
// Did the item already have an image?
if (oldKey) {
// Delete the old image
[[BNRImageStore sharedStore]deleteImageForKey:oldKey];
}
UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
// Create a CFUUID object - it knows how to create unique identifier strings
CFUUIDRef newUniqueID = CFUUIDCreate(kCFAllocatorDefault);
// Create a string from unique identifier
CFStringRef newUniqueIDString = CFUUIDCreateString(kCFAllocatorDefault, newUniqueID); // Incompatible integer to pointer conversion initializing
// Use that unique ID to set our item's imageKey
NSString *key = (__bridge NSString *)newUniqueIDString;
[item setImageKey:key];
// Store image in the BNRImageStore with this key
[[BNRImageStore sharedStore] setImage:image forKey:[item imageKey]];
CFRelease(newUniqueIDString);
CFRelease(newUniqueID);
[imageView setImage:image];
if ([[UIDevice currentDevice]userInterfaceIdiom]==UIUserInterfaceIdiomPad) {
// If on the phone, the image picker is presented modally. Dismiss it.
[self dismissViewControllerAnimated:YES completion:nil];
} else {
// If on the pad, the image picker is in the popover. Dismiss the popover.
[imagePickerPopover dismissPopoverAnimated:YES];
imagePickerPopover = nil;
}
}
-(BOOL)textFieldShouldReturn:(UITextField *)textField
{
[textField resignFirstResponder];
return YES;
}
-(void)save:(id)sender
{
[[self presentingViewController]dismissViewControllerAnimated:YES
completion:nil];
}
-(void)cancel:(id)sender
{
// If the user cancelled, then remove the BNRItem from the store
[[BNRItemStore sharedStore]removeItem:item]; // No known class method for selector 'sharedStore'
[[self presentingViewController]dismissViewControllerAnimated:YES completion:nil];
}
DetailViewController.h
#import <UIKit/UIKit.h>
#class BNRItem;
#interface DetailViewController : UIViewController <UINavigationControllerDelegate, UIImagePickerControllerDelegate,UITextFieldDelegate, UIPopoverControllerDelegate>
{
__weak IBOutlet UITextField *nameField;
__weak IBOutlet UITextField *serialNumberField;
__weak IBOutlet UITextField *valueField;
__weak IBOutlet UILabel *dateLabel;
__weak IBOutlet UIImageView *imageView;
UIPopoverController *imagePickerPopover;
}
#property(nonatomic,strong)BNRItem *item;
-(id)initForNewItem:(BOOL)isNew;
- (IBAction)takePicture:(id)sender;
- (IBAction)backgroundTapped:(id)sender;
#end
BNRItemStore.m
#import "BNRItemStore.h"
#import "BNRItem.h"
#implementation BNRItemStore
+ (BNRItemStore *)defaultStore
{
static BNRItemStore *defaultStore = nil;
if(!defaultStore)
defaultStore = [[super allocWithZone:nil] init];
return defaultStore;
}
+ (id)allocWithZone:(NSZone *)zone
{
return [self defaultStore];
}
- (id)init
{
self = [super init];
if(self) {
allItems = [[NSMutableArray alloc] init];
}
return self;
}
- (void)removeItem:(BNRItem *)p
{
[allItems removeObjectIdenticalTo:p];
}
- (NSArray *)allItems
{
return allItems;
}
- (void)moveItemAtIndex:(int)from
toIndex:(int)to
{
if (from == to) {
return;
}
// Get pointer to object being moved so we can re-insert it
BNRItem *p = [allItems objectAtIndex:from];
// Remove p from array
[allItems removeObjectAtIndex:from];
// Insert p in array at new location
[allItems insertObject:p atIndex:to];
}
- (BNRItem *)createItem
{
BNRItem *p = [BNRItem randomItem];
[allItems addObject:p];
return p;
}
#end
BNRItemStore.h
#import <Foundation/Foundation.h>
#class BNRItem;
#interface BNRItemStore : NSObject
{
NSMutableArray *allItems;
}
+ (BNRItemStore *)defaultStore;
- (void)removeItem:(BNRItem *)p;
- (NSArray *)allItems;
- (BNRItem *)createItem;
- (void)moveItemAtIndex:(int)from
toIndex:(int)to;
#end
You are calling +sharedStore on BNRItemStore where your error occurs. This is because it really does not exist according to the code you posted.
All of the others calling +sharedStore are using the one presumably made available by BNRImageStore which you didn't provide. I assume it exists in that class? :)
In short, change:
[[BNRItemStore sharedStore]removeItem:item];
to
[[BNRImageStore sharedStore]removeItem:item];
Issue
Description
The following code results in load method of TTModel not being called. I've stepped it through the debugger, as well as stepping through the TTCatalog application. The only difference between the two that I can see, is that when the catalog sets it's DataSource in the createModel method of the controller, TTModel's load method gets called, whereas mine does not.
About the Code
I've commented the specific areas of code, to tell what they should be doing and what problem is happening, but I included all of it for completion's sake.
You should look at specifically
PositionsController's createModel method
PositionsList's load method
Those are the areas where the issue is, and would be the best place to start.
Code
PositionsController : TTTableViewController
- (id)initWIthNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self)
{
self.title = #"Positions";
self.variableHeightRows = NO;
self.navigationBarTintColor = [UIColor colorWithHexString:#"1F455E"];
}
return self;
}
//This method here should result in a call to the PositionsList load method
- (void)createModel
{
PositionsDataSource *ds = [[PositionsDataSource alloc] init];
self.dataSource = ds;
[ds release];
}
- (void)loadView
{
[super loadView];
self.view = [[[UIView alloc] initWithFrame:TTApplicationFrame()] autorelease];
self.tableView = [[[UITableView alloc] initWithFrame:TTApplicationFrame() style:UITableViewStylePlain] autorelease];
self.tableView.backgroundColor = [UIColor colorWithHexString:#"E2E7ED"];
self.tableView.separatorColor = [UIColor whiteColor];
self.tableView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
//self.tableView.delegate = self;
[self.view addSubview:self.tableView];
}
//Override UITableViewDelegate creation method, so we can add drag to refresh
- (id<TTTableViewDelegate>) createDelegate {
TTTableViewDragRefreshDelegate *delegate = [[TTTableViewDragRefreshDelegate alloc] initWithController:self];
return [delegate autorelease];
}
PositionsDataSource : TTListDataSource
#implementation PositionsDataSource
#synthesize positionsList = _positionsList;
-(id)init
{
if (self = [super init])
{
_positionsList = [[PositionsList alloc] init];
self.model = _positionsList;
}
return self;
}
-(void)dealloc
{
TT_RELEASE_SAFELY(_positionsList);
[super dealloc];
}
-(void)tableViewDidLoadModel:(UITableView*)tableView
{
self.items = [NSMutableArray array];
}
-(id<TTModel>)model
{
return _positionsList;
}
#end
PositionsList : NSObject <TTModel>
#implementation PositionsList
//============================================================
//NSObject
- (id)init
{
if (self = [super init])
{
_delegates = nil;
loaded = NO;
client = [[Client alloc] init];
}
return self;
}
- (void)dealloc
{
TT_RELEASE_SAFELY(_delegates);
[client dealloc];
[super dealloc];
}
//==============================================================
//TTModel
- (NSMutableArray*)delegates
{
if (!_delegates)
{
_delegates = TTCreateNonRetainingArray();
}
return _delegates;
}
-(BOOL)isLoadingMore
{
return NO;
}
-(BOOL)isOutdated
{
return NO;
}
-(BOOL)isLoaded
{
return loaded;
}
-(BOOL)isEmpty
{
//return !_positions.count;
return NO;
}
-(BOOL)isLoading
{
return YES;
}
-(void)cancel
{
}
//This method is never called, why is that?
-(void)load:(TTURLRequestCachePolicy)cachePolicy more:(BOOL)more
{
//This method is not getting called
//When the PositionsController calls self.datasource, load should be called,
//however it isn't.
[_delegates perform:#selector(modelDidStartLoad:) withObject:self];
[client writeToServer:self dataToSend:#""];
}
-(void)invalidate:(BOOL)erase
{
}
#end
Short answer: return NO instead of YES for isLoading in your PositionList.
For a longer explanation:
If you dig through the Three20 source, you'll find that setting the dataSource on a view controller sets the model, refreshing the model and potentially calling load. Here is the code called when the TTModelViewController refreshes:
- (void)refresh {
_flags.isViewInvalid = YES;
_flags.isModelDidRefreshInvalid = YES;
BOOL loading = self.model.isLoading;
BOOL loaded = self.model.isLoaded;
if (!loading && !loaded && [self shouldLoad]) {
[self.model load:TTURLRequestCachePolicyDefault more:NO];
} else if (!loading && loaded && [self shouldReload]) {
[self.model load:TTURLRequestCachePolicyNetwork more:NO];
} else if (!loading && [self shouldLoadMore]) {
[self.model load:TTURLRequestCachePolicyDefault more:YES];
} else {
_flags.isModelDidLoadInvalid = YES;
if (_isViewAppearing) {
[self updateView];
}
}
}
Your PositionList object is returning YES for isLoading and NO for isLoaded. This means that Three20 thinks your model is loading when it isn't. You may also need to implement shouldLoad if it doesn't return YES by default.
I have a a singleton class here is the code
#import <Foundation/Foundation.h>
#import "CustomColor.h"
#interface Properties : NSObject {
UIColor *bgColor;
CustomColor *bggColor;
}
#property(retain) UIColor *bgColor;
#property (retain) CustomColor *bggColor;
+ (id)sharedProperties;
#end
#import "Properties.h"
static Properties *sharedMyProperties = nil;
#implementation Properties
#synthesize bgColor;
#synthesize bggColor;
#pragma mark Singleton Methods
+ (id)sharedProperties
{
#synchronized(self)
{
if(sharedMyProperties == nil)
[[self alloc] init];
}
return sharedMyProperties;
}
+ (id)allocWithZone:(NSZone *)zone
{
#synchronized(self)
{
if(sharedMyProperties == nil)
{
sharedMyProperties = [super allocWithZone:zone];
return sharedMyProperties;
}
}
return nil;
}
- (id)copyWithZone:(NSZone *)zone
{
return self;
}
- (id)retain {
return self;
}
- (unsigned)retainCount {
return UINT_MAX; //denotes an object that cannot be released
}
- (void)release {
// never release
}
- (id)autorelease {
return self;
}
- (id)init {
if (self = [super init])
{
bgColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:1.0];
FSColor *bc = [[FSColor alloc] init];
bc.red = bc.green = bc.blue = bc.hue = bc.sat = bc.bri = 0;
bggColor = bc;
}
return self;
}
- (void)dealloc
{
// Should never be called, but just here for clarity really.
[bgColor release];
[bggColor release];
[super dealloc];
}
#end
I have a UIView' subclass. in which i am using it. I am calling drawRect method after each second. It only run once and then app crashes.
- (void)drawRect:(CGRect)rect
{
Properties *sharedProprties = [Properties sharedProperties];
…...
….
CGContextSetFillColorWithColor(context, [[sharedProprties bgColor] CGColor]);
…..
}
What if you do self.bgColor = [UIColor colorWithRed:...]?
Without the self. I think you may be accessing the ivar directly, and therefore assigning it an autoreleased object which won't live very long (rather than using the synthesized property setter, which would retain it). I could be wrong about this, I'm stuck targeting older Mac OS X systems so I haven't been able to play much with Objective-C 2.0.
Your static sharedProperties gets never assigned. It is missing in the init method or in the sharedProperties static method.
Here's a sample pattern for singletons (last post)
Also accessing properties without self. may cause bad access errors too.
Regards
Not an answer, but note that a simple call to [Properties alloc] will mean it's no longer a singleton!
+ (id)sharedProperties
{
#synchronized(self)
{
if(sharedMyProperties == nil)
{
sharedMyProperties = [[self alloc] init];
}
}
return sharedMyProperties;
}