Is it possible to make a blinking UILabel in Cocoa Touch or do I need an UIview with Core Animation for that?
Take Martin's advice, and then have a look at NSTimer to handle the "blink" actions.
+ scheduledTimerWithTimeInterval:target:selector:userInfo:repeats:
All UIViews (including UILabel) has a hidden property which you can toggle on and off to make it "blink".
For fun, I decided to write this subclassing NSOperation.
Excerpt from BlinkingLabelOperation.m
- (void)main {
SEL update = #selector(updateLabel);
[self setThreadPriority:0.0];
while (![self isCancelled]) {
if (label_ == nil)
break;
[NSThread sleepForTimeInterval:interval_];
[self performSelectorOnMainThread:update withObject:nil waitUntilDone:YES];
}
}
- (void)updateLabel {
BlinkingColors *currentColors = nil;
if (mode_)
currentColors = blinkColors_;
else
currentColors = normalColors_;
[label_ setTextColor:currentColors.textColor];
[label_ setBackgroundColor:currentColors.backgroundColor];
mode_ = !mode_;
}
Sample view controller code:
- (void)viewDidLoad
{
[super viewDidLoad];
BlinkingColors *blinkColors = [[BlinkingColors alloc] initWithBackgroundColor:[UIColor whiteColor]
textColor:[UIColor redColor]];
BlinkingLabelOperation *blinkingOp = [[BlinkingLabelOperation alloc] initWithLabel:clickLabel freq:1.0 blinkColors:blinkColors];
// put the operation on a background thread
NSOperationQueue *queue = [[[NSOperationQueue alloc] init] autorelease];
[queue addOperation:blinkingOp];
[blinkColors release];
}
For a complete listing, you will find it here. Please leave comments and let me know what are your thoughts.
Related
I just trying to get to QLPreviewController.view. Indeed, I want to catch a tap event on its view to show/hide toolbar etc. I am trying:
QLPreviewController* qlpc = [QLPreviewController new];
qlpc.delegate = self;
qlpc.dataSource = self;
qlpc.currentPreviewItemIndex=qlIndex;
[navigator pushViewController:qlpc animated:YES];
qlpc.title = [path lastPathComponent];
[qlpc setToolbarItems:[NSArray arrayWithObjects:self.dirBrowserButton,self.space, self.editButton, self.btnSend, nil] animated:YES];
UITapGestureRecognizer* gestTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(showControls:)];
gestTap.cancelsTouchesInView=NO;
[qlpc.view addGestureRecognizer:[gestTap autorelease]];
[qlpc release];
And nothing happens
If I attach UITapRecognizer onto navigationController.view, it fires only if I touch toolbar/navbar. UISwipeGestureRecognizer works fine in that case.
I tried to attach a transparent overlay view and add gesture recognizers on it, but no luck.
Well, I saw some apps that implements such a feature so obviously it is possible, but how?
Sorry, I googled all day long and didn't find any solution. Please, help me.
With your solution, does the QLPreviewController's view still recieve touches? I've tried to do something similar (I'm stealing the view from QLPreviewController to use it) and it looks like my overlay view doesn't let anything pass trough to the view lying behind it.
I have been working on this problem today and the suggestion to override -(void)contentWasTappedInPreviewContentController:(id)item {} is close but when you do you mess with the preview controllers handling.
So I stopped overriding that method and instead created a RAC signal that fires whenever the method is called. This does not mess with the default behavior of QL. I am doing it in a subclass of the QLPreviewController but that shouldn't be necessary.
I have a property on my class:
#property RACSignal *contentTapped;
Then in my init method of my subclass of QLPreviewController:
_contentTapped = [self rac_signalForSelector:#selector(contentWasTappedInPreviewContentController:)];
Now in another class or even internally you can use the signal like this:
previewController.contentTapped subscribeNext:^(id x) {
// Put your handler here!
}];
Here is my solution (to use KVO), where I'm monitoring navigation bar status - and showing toolbar when needed (it seems that it hides toolbar by itself when tapped)
#define kNavigationBarKeyPath #"navigationBar.hidden"
static void * const NavigationBarKVOContext = (void*)&NavigationBarKVOContext;
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
[self.navigationController setToolbarHidden:NO];
[self.navigationController addObserver:self forKeyPath:kNavigationBarKeyPath options:NSKeyValueObservingOptionPrior context:NavigationBarKVOContext];
}
- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
[self.navigationController removeObserver:self forKeyPath:kNavigationBarKeyPath];
}
And
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
if ( context == NavigationBarKVOContext ) {
BOOL prior = [change[NSKeyValueChangeNotificationIsPriorKey] boolValue];
if ( prior && self.navigationController.toolbarHidden ) {
dispatch_async(dispatch_get_main_queue(), ^{
[self.navigationController setToolbarHidden:NO animated:YES];
});
}
}
}
I found none of the answers here to work, but the one that did for me was to subclass QLPreviewController and override viewDidAppear as so:
- (void)viewDidAppear:(BOOL)animated
{
UITapGestureRecognizer *gestTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(showControls:)];
gestTap.cancelsTouchesInView = NO;
[self.view addGestureRecognizer:[gestTap autorelease]];
}
Ok, solution is very simple.
just added an overlay view onto keyWindow. Attached gesture recognizers onto overlay and it works.
QLPreviewController* qlpc = [QLPreviewController new];
qlpc.delegate = self;
qlpc.dataSource = self;
qlpc.currentPreviewItemIndex=qlIndex;
[navigator pushViewController:qlpc animated:YES];
qlpc.title = [path lastPathComponent];
UIView* overlay = [[[UIView alloc] initWithFrame:navigator.view.bounds] autorelease];
[[[UIApplication sharedApplication] keyWindow] addSubview:overlay];
[overlay setNeedsDisplay];
[qlpc setToolbarItems:[NSArray arrayWithObjects:self.dirBrowserButton,self.space, self.editButton, self.btnSend, nil] animated:YES];
UITapGestureRecognizer* gestTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(showControls:)];
gestTap.cancelsTouchesInView=NO;
[overlay addGestureRecognizer:[gestTap autorelease]];
[qlpc release];
Subclass QLPreviewController and then override
-(void)contentWasTappedInPreviewContentController:(id)item
{}
Thats its !
I've added the ELCimagepicker (https://github.com/Fingertips/ELCImagePickerController) to my project and it works perfectly, allowing the user to select multiple images for a slideshow. But when you click 'Save', there can be a lengthy delay depending on how many photos were added.
I've been trying to add a UIActivityIndicator when the user clicks 'Save', but having trouble due to the modal view that is presented. I can call a method from the activity that ELCimagepicker presents (ELCImagePickerController) and this gets actioned by the activity handling the presenting of the image picker. But whenever I try to add to the view, it isn't shown as the modal is on top of the activity indicator.
I've tried using bringSubviewToFront, I've tried adding the code directly to the imagepicker method file with [[self parentViewController] addSubView], but no luck.
Here's the latest code I tried: (indicator is declared in the .h file as UIActivityIndicator *indicator)
indicator = [[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
indicator.hidden=false;
[self.navigationController.view addSubview:self.indicator];
[self.navigationController.view bringSubviewToFront:self.indicator];
[indicator startAnimating];
if([delegate respondsToSelector:#selector(elcImagePickerController:showIndicator:)]) {
[delegate performSelector:#selector(elcImagePickerController:showIndicator:) withObject:self withObject:#"test"];
}
Has anyone had any success with adding a UIActivityIndicator on top of the ELCimagepicker, or another modal view handled by another class?
I've tried MBProgressHUD but couldn't get that working quite right either - it would show up when I used it in the ELCimagepicker class, but crashed on removal with:
bool _WebTryThreadLock(bool), 0x42368e0: Tried to obtain the web lock from a thread other than the main thread or the web thread. This may be a result of calling to UIKit from a secondary thread. Crashing now...
Any help would be fantastic.
Thanks.
I have figure out your problem. You can do this as below..
-(void)selectedAssets:(NSArray*)_assets {
UIActivityIndicatorView * activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
UIViewController * topView = [self.viewControllers objectAtIndex:[self.viewControllers count]-1];
activityIndicator.center = CGPointMake(topView.view.frame.size.width/2, topView.view.frame.size.height/2);
[activityIndicator setHidden:NO];
[topView.view addSubview:activityIndicator];
[topView.view bringSubviewToFront:activityIndicator];
[activityIndicator startAnimating];
[self performSelector:#selector(doProcess:) withObject:_assets afterDelay:2.1];
}
- (void) doProcess:(NSArray *)_assets {
NSMutableArray *returnArray = [[[NSMutableArray alloc] init] autorelease];
for(ALAsset *asset in _assets) {
NSMutableDictionary *workingDictionary = [[NSMutableDictionary alloc] init];
[workingDictionary setObject:[asset valueForProperty:ALAssetPropertyType] forKey:#"UIImagePickerControllerMediaType"];
[workingDictionary setObject:[UIImage imageWithCGImage:[[asset defaultRepresentation] fullScreenImage]] forKey:#"UIImagePickerControllerOriginalImage"];
[workingDictionary setObject:[[asset valueForProperty:ALAssetPropertyURLs] valueForKey:[[[asset valueForProperty:ALAssetPropertyURLs] allKeys] objectAtIndex:0]] forKey:#"UIImagePickerControllerReferenceURL"];
[returnArray addObject:workingDictionary];
[workingDictionary release];
}
[self popToRootViewControllerAnimated:NO];
[[self parentViewController] dismissModalViewControllerAnimated:YES];
if([delegate respondsToSelector:#selector(elcImagePickerController:didFinishPickingMediaWithInfo:)]) {
[delegate performSelector:#selector(elcImagePickerController:didFinishPickingMediaWithInfo:) withObject:self withObject:[NSArray arrayWithArray:returnArray]];
}
}
Let me know if this answer help you ...
Thanks,
MinuMaster
It looks like you are updating UI on a background thread. All UIKit updates are to be done in the main thread. So I recommend you execute methods doing UI updates using performSelectorOnMainThread:withObject:.
I solved the issue like this
activityIndicatorObject = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
// Set Center Position for ActivityIndicator
activityIndicatorObject.center = CGPointMake(150, 250);
activityIndicatorObject.backgroundColor=[UIColor grayColor];
// Add ActivityIndicator to your view
[self.view addSubview:activityIndicatorObject];
activityIndicatorObject.hidesWhenStopped=NO;
[activityIndicatorObject startAnimating];
I am implementing a simple in-app browser. In my home view (UITableViewController), I have something like:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
WebViewController *webViewController = [[WebViewController alloc] init];
switch (indexPath.row) {
case 0:
webViewController.stringURL = #"http://www.google.com";
break;
case 1:
webViewController.stringURL = #"http://www.bing.com";
break;
default:
webViewController.stringURL = #"http://stackoverflow.com";
break;
}
[self.navigationController pushViewController:webViewController animated:YES];
[webViewController release];
}
The app crashed after I repetitively navigated back and forth between my home view and webViewControllera few times.
Inside WebViewController class, I have nothing but a [UIWebView *webView] and a [UIActivityIndicatorView *activityIndicator]. Both are with attributes nonatomic, retain. Here is the implementation.
#import "WebViewController.h"
#implementation WebViewController
#synthesize webView, activityIndicator, stringURL;
- (void)dealloc
{
[self.webView release];
self.webView.delegate = nil;
[self.activityIndicator release];
[super dealloc];
}
-(void)loadView {
UIView *contentView = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
self.view = contentView;
CGRect webFrame = [[UIScreen mainScreen] applicationFrame];
webFrame.origin.y = 0.0f;
self.webView = [[UIWebView alloc] initWithFrame:webFrame];
self.webView.backgroundColor = [UIColor blueColor];
self.webView.scalesPageToFit = YES;
self.webView.autoresizingMask = (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight);
self.webView.delegate = self;
[self.view addSubview: self.webView];
[self.webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:self.stringURL]]];
self.activityIndicator = [[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
self.activityIndicator.frame = CGRectMake(0.0, 0.0, 30.0, 30.0);
self.activityIndicator.center = self.view.center;
[self.view addSubview: self.activityIndicator];
}
- (void)viewDidLoad
{
[super viewDidLoad];
[self loadView];
}
- (void)webViewDidStartLoad:(UIWebView *)webView
{
// starting the load, show the activity indicator in the status bar
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
[activityIndicator startAnimating];
}
- (void)webViewDidFinishLoad:(UIWebView *)webView
{
// finished loading, hide the activity indicator in the status bar
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
[activityIndicator stopAnimating];
}
#end
I just ran my app in Instruments using the Zombies template, which shows -[UIWebView webView:didReceiveTitle:forFrame:] is the Zombie call. But I still can’t figure out what is actually the problem.
(Please download trace if needed)
Any help is greatly appreciated!
[Update]:
As #7KV7 and #David pointed out, there is an obvious bug in my dealloc function. I should call self.webView.delegate=nil; first before I release self.webView. Sorry about that. Unfortunately, after I fix it, the app still crashes in the same way.
If I delete [webViewController release]; from the first code block, the crash actually is gone. But obviously, there will be memory leak.
First of all, remove that call to loadView in viewDidLoad. The framework will the call the method when it doesn't find a view provided in XIB file. Second, your loadView is filled with memory leaks. You are allocating, initializing and retaining an object every time the method is called. So you are taking ownership twice and releasing it only once in the dealloc.
The objects are not being properly deallocated. You should do something like alloc-init-autorelease to solve this. Next thing is the that every time the controller gets loaded, because of your call to loadView, you end up creating two web view objects and two requests. You lose reference to one of them as you reassign. Herein, lies the problem mentioned in the title. You aren't able to reset the delegate of a web view object that has your controller as a delegate. Imagine a request being completed soon after you leave. Here the message will go to a zombie object. This is a pretty good example for why you need to nil out your delegates.
- (void)dealloc
{
self.webView.delegate = nil;
[self.webView release];
[self.activityIndicator release];
[super dealloc];
}
Try this dealloc. You were releasing the webview and then setting the delegate as nil. You should first set the delegate as nil and then release it. Hope this solves the issue.
I think what's happening is that you are going back while the page is still loading so the controller gets deallocated and then the webview finishes loading.
Try calling [webView stopLoading] in your viewDidUnload method to make sure this isn't happening.
Don't know if it's the cause of your problem, but this is definitely wrong:
[self.webView release];
self.webView.delegate = nil;
You cannot (safely) refer to self.webView after you release it!
Instead of pushing webViewController,add its view to self.view .
Dont call [self loadView]; in viewDidLoad.
I am trying to implement AQGridView based upon the ImageDemo in the /examples folder. I have a view controller with the following declaration:
#interface ImageDemoViewController : UIViewController <AQGridViewDelegate, AQGridViewDataSource, ImageDemoCellChooserDelegate>
{
...
None of the datasource methods in my view controller such as
- (NSUInteger) numberOfItemsInGridView: (AQGridView *) aGridView
{
return ( [images count] );
}
are being called. Here is where I setup the gridview making my view controller the delegate for the gridview.
- (void)viewDidLoad
{
[super viewDidLoad];
self.gridView.autoresizingMask = UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;
self.gridView.autoresizesSubviews = YES;
self.gridView.delegate = self;
self.gridView.dataSource = self;
images=[[NSMutableArray alloc]init];
[images addObject:#"http://t3.gstatic.com/images?q=tbn:ANd9GcTOXAzFMoK441mcn9V0OemVe_dtAuCpGjBkLrv4rffyOjYIo45BEw"];
[self.gridView reloadData];
}
If I set a breakpoint on
[self.gridView reloadData];
the line is executed but reloadData method in AQGridView is not called. The only difference from the ImageDemo is I do not have a .xib file for the view controller. Have I forgotten to hook up something, resulting in the datasource methods not being called?
If there's no XIB, then who's creating the gridView? If it's never created, then it would be NIL, and you'd have the behavior you describe. (If that's it, then just adding:
self.gridview = [AQGridView alloc] initWithFrame: ...]; should suffice.
Had the same problem. Solved by replacing the view with the AQGridView.
[self.view addSubview:self.gridView]
self.view = self.gridView;
Full method:
- (void) viewDidLoad
{
[super viewDidLoad];
self.gridView = [[AQGridView alloc] init];
self.gridView.autoresizingMask = UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;
self.gridView.autoresizesSubviews = YES;
self.gridView.delegate = self;
self.gridView.dataSource = self;
self.view = self.gridView;
[self.gridView reloadData];
}
Maybe you could try implementing this:
- (void)LoadSearch
{
NSURL *test1 = [NSURL URLWithString:#"http://www.4ddraws.com/search_iphone.asp"];
NSURLRequest *test = [NSURLRequest requestWithURL:test1];
[web4D setScalesPageToFit:(YES)];
[web4D loadRequest:test];
}
I have a UITabbBarController with a UITableView. Under certain circumstances the TabBarControllers dataset requires updating when a user arrives from another view,
e.g. the initial load when the TabBarController is called the first time, or when the settings are changed.
This dataset update takes about 2 seconds and I want to show an UIActivityIndicatorView.
Trouble is that when I enter from another view I don't know which view to attach it to, since the loading of the tabbarController is carried out in the viewWillAppear method.
Any clues how I can go about this?
I've done this sort of thing in the viewDidAppear method. My code kicks off a background task to load the data from a url. It also hands the background task a selector of a method to call on the controller when it is done. That way the controller is notified that the data has been downloaded and can refresh.
I don't know if this is the best way to do this, but so far it's working fine for me :-)
To give some more details, in addition to the selector of the method to call when the background task has loaded the data, I also and it a selector of a method on the controller which does the loading. That way the background task manages whats going on, but the view controller provides the data specific code.
Here's there viewDidAppear code:
- (void) viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
if (reloadData) {
BackgroundTask *task = [[BackgroundTask alloc] initWithMethod:#selector(loadData) onObject:self];
task.superView = self.view.superview;
task.notifyWhenFinishedMethod = #selector(loadFinished);
[task start];
[task release];
}
}
The background task has an optional superView because it will add a new UIView to it containing an activity indicator.
BackgroundTask.m looks like this:
#implementation BackgroundTask
#synthesize superView;
#synthesize longRunningMethod;
#synthesize notifyWhenFinishedMethod;
#synthesize obj;
- (BackgroundTask *) initWithMethod:(SEL)aLongRunningMethod onObject:(id)aObj {
self = [super init];
if (self != nil) {
self.longRunningMethod = aLongRunningMethod;
self.obj = aObj;
}
return self;
}
- (void) start {
// Fire into the background.
NSThread *thread = [[NSThread alloc] initWithTarget:self selector:#selector(execute:)object:nil];
thread.name = #"BackgroundTask thread";
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(taskFinished:) name:NSThreadWillExitNotification object:thread];
[thread start];
[thread release];
}
- (void) execute:(id)anObject {
// New thread = new pool.
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
if (self.superView != nil) {
busyIndicatorView = [[BusyIndicator alloc] initWithSuperview:self.superView];
[busyIndicatorView performSelectorOnMainThread:#selector(addToSuperView)withObject:nil waitUntilDone:YES];
}
// Do the work on this thread.
[self.obj performSelector:self.longRunningMethod];
if (self.superView != nil) {
[busyIndicatorView performSelectorOnMainThread:#selector(removeFromSuperView)withObject:nil waitUntilDone:YES];
}
[pool release];
}
- (void) taskFinished:(NSNotification *)notification {
[[NSNotificationCenter defaultCenter] removeObserver:self name:NSThreadWillExitNotification object:notification.object];
[self performSelectorOnMainThread:#selector(notifyObject)withObject:nil waitUntilDone:NO];
}
- (void) notifyObject {
// Tell the main thread we are done.
if (self.notifyWhenFinishedMethod != nil) {
[self.obj performSelectorOnMainThread:self.notifyWhenFinishedMethod withObject:nil waitUntilDone:NO];
}
}
- (void) dealloc {
self.notifyWhenFinishedMethod = nil;
self.superView = nil;
self.longRunningMethod = nil;
self.obj = nil;
[super dealloc];
}
#end
Finally as I said I put up a activity indicator. I have a xib which contains a 50% transparent blue background with an activity indicator in the middle. There is a controller for it which has this code:
#implementation BusyIndicator
#synthesize superView;
#synthesize busy;
- (BusyIndicator *) initWithSuperview:(UIView *)aSuperView {
self = [super initWithNibName:#"BusyIndicator" bundle:nil];
if (self != nil) {
self.superView = aSuperView;
}
return self;
}
- (void) addToSuperView {
// Adjust view size to match the superview.
[self.superView addSubview:self.view];
self.view.frame = CGRectMake(0,0, self.superView.frame.size.width, self.superView.frame.size.height);
//Set position of the indicator to the middle of the screen.
int top = (int)(self.view.frame.size.height - self.busy.frame.size.height) / 2;
self.busy.frame = CGRectMake(self.busy.frame.origin.x, top, self.busy.frame.size.width, self.busy.frame.size.height);
[self.busy startAnimating];
}
- (void) removeFromSuperView {
[self.busy stopAnimating];
[self.view removeFromSuperview];
}
- (void) dealloc {
self.superView = nil;
[super dealloc];
}
#end
Hoep this helps.