I parse HTML Data from a Website with the help of the TFHppleElement. Now during the parsing in the for loop I want to update the progressView but it isn't working. Why?
My Code:
ParseHTMLData.m
for (...) {
...
for (...) {
for (...) {
...
}
}
SecondViewController *svc = [[SecondViewController alloc] init];
float prog = 0.9f; //For testing a fix value
[svc setProgressAnimated:[NSNumber numberWithFloat:prog]];
}
SecondViewController.m
-(void)setProgressAnimated: (NSNumber *)number;
{
[self.progressView setProgress:[number floatValue] animated:YES];
}
I got working it by doing it like this. So it is parsing in the background and I can update the UI.
dispatch_async( dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
for (...) {
...
for (...) {
for (...) {
...
}
}
}
});
Related
I have this code here to check on the existence of the ViewController. And unfortunately it doesn't work. The thing is, it is executed at the moment of another VC popping from the Navigation Stack:
- (void) leftViewDidHide{
if ([((AppDelegate *)[UIApplication sharedApplication].delegate).frontViewController.navigationController.viewControllers objectAtIndex:1]) {
SGServerListViewController *sample = [[[((AppDelegate *)[UIApplication sharedApplication].delegate).frontViewController.navigationController.viewControllers objectAtIndex:1]childViewControllers] objectAtIndex:0];
[sample.serverTableView setUserInteractionEnabled:YES];
}
}
The app crashes with an exception breakpoint pointing me to the line with an if statement. Any ideas on what could be wrong here? I'm just trying to check if this VC is there and if it is - execute the code.
NSArray *viewControlles = [self.navigationController.viewControllers];
for (int i = 0 ; i <viewControlles.count; i++){
if ([YourVC isKindOfClass:[viewControlles objectAtIndex:i]]) {
//Execute your code
}
}
NSArray *controllerArray = [self.navigationController.viewControllers];
//will get all the controllers added to UINavigationController.
for (id controller in controllerArray)
{
// iterate through the array and check for your controller
if ([controller isKindOfClass:[checkYourController class]])
{
//do your stuff here
}
}
just for an idea containsObject: method of NSArray class might also work.
-(BOOL)isControllerAlreadyOnNavigationControllerStack{
for (UIViewController *vc in self.navigationController.viewControllers) {
if ([vc isKindOfClass:Controller.class]) {
[self.navigationController popToViewController:vc animated:NO];
return YES;
}
}
return NO;
}
if (![self isControllerAlreadyOnNavigationControllerStack]) {
//push controller
}
- (void) leftViewDidHide{
if ([((AppDelegate *)[UIApplication sharedApplication].delegate).frontViewController.navigationController.viewControllers count] == 1) {
SGServerListViewController *sample = [[[((AppDelegate *)[UIApplication sharedApplication].delegate).frontViewController.navigationController.viewControllers objectAtIndex:1]childViewControllers] objectAtIndex:0];
[sample.serverTableView setUserInteractionEnabled:YES];
}
}
You can do that (checking if a ViewController on Navigation Stack exists) with this code:
if navigationController?.viewControllers.count > 1 {
for root in (self.navigationController?.viewControllers)! {
if root is ViewController {
let i = root as? ViewController
i?.table.removeFromSuperview()
}
}
}
self.navigationController?.popToRootViewControllerAnimated(true)
NSArray *viewControlles = self.navigationController.viewControllers;
for (int i = 0 ; i <viewControlles.count; i++){
if ([[viewControlles objectAtIndex:i] isKindOfClass:[RequiredViewController class]]) {
//Enter your code
}
}
I have intercepted URL opening by doing the following:
- (BOOL)openURL:(NSURL *)url{
URLViewController * web = [[URLViewController alloc] init];
web.url = url;
UINavigationController * nav = [[UINavigationController alloc] initWithRootViewController:web];
[nav.navigationBar setTintColor:[UIColor blackColor]];
[nav setModalPresentationStyle:UIModalPresentationFormSheet];
[self.detailViewController presentModalViewController:nav animated:NO];
[web release];
[nav release];
return YES;
}
I have a UITextView in which detects URL and when clicking on the URL it opens up the link in a ModalViewController. Full detail on what's going on can be seen here. Now the issue is, what if I want to open a URL in safari, is it still possible?
You should add an override flag indicating whether you want to exercise control or not.
#interface MyApplication : UIApplication {
}
-(BOOL)openURL:(NSURL *)url withOverride:(BOOL)override;
#end
#implementation MyApplication
-(BOOL)openURL:(NSURL *)url withOverride:(BOOL)override {
if ( !override ) {
return [super openURL:url];
}
if ([self.delegate openURL:url]) {
return YES;
} else {
return [super openURL:url];
}
}
-(BOOL)openURL:(NSURL *)url{
return [self openURL:url withOverride:YES];
}
#end
So now all calls that you want to bypass can be sent like this.
[[MyApplication sharedApplication] openURL:url withOverride:NO];
Original Answer
This is what you should do. Put it before the return YES; statement.
if ( [super canOpenURL:aURL] ) {
return [super openURL:aURL];
}
I am trying to use UIMenuController for a dynamical menu (titles and actions come from a server). The problem is that I have to use UIMenuItems initWithTitle:action: where action is a #selector.
I can use #selector(dispatch:) but then I am not able to distinguish which of the items the user pressed. - (void)dispatch:(id)sender { NSLog(#"%#", sender); } says it is a UIMenuController and It don't have a method which would tell which menu item was pressed.
I can't just write 100 methods to dispatch every possible selector, ok there will not be more then 10 but still, this seems not a good idea.
Do I have to create dynamic methods for each such selector? http://developer.apple.com/mac/library/documentation/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtDynamicResolution.html? This seems odd too.
Any better propositions then this two?
// This approach doesn't work.
- (void)showMenu {
[self becomeFirstResponder];
NSMutableArray *menuItems = [[NSMutableArray alloc] init];
UIMenuItem *item;
for (MLAction *action in self.dataSource.actions) {
item = [[UIMenuItem alloc] initWithTitle:action.title action:#selector(action:)];
[menuItems addObject:item];
[item release];
}
UIMenuController *menuController = [UIMenuController sharedMenuController];
menuController.menuItems = menuItems;
[menuItems release];
[menuController update];
[menuController setMenuVisible:YES animated:YES];
}
- (void)action:(id)sender {
NSLog(#"%#", sender); // gives UIMenuController instead of UIMenuItem
// I can not know which menu item was pressed
}
// This approach is really ugly.
- (void)showMenu {
[self becomeFirstResponder];
NSMutableArray *menuItems = [[NSMutableArray alloc] initWithCapacity:5];
UIMenuItem *item;
NSInteger i = 0;
for (MLAction *action in self.dataSource.actions) {
item = [[UIMenuItem alloc] initWithTitle:action.text
action:NSSelectorFromString([NSString stringWithFormat:#"action%i:", i++])];
[menuItems addObject:item];
[item release];
}
UIMenuController *menuController = [UIMenuController sharedMenuController];
menuController.menuItems = menuItems;
[menuItems release];
[menuController update];
[menuController setMenuVisible:YES animated:YES];
}
- (void)action:(NSInteger)number {
NSLog(#"%i", number); // gives the index of the action in the menu.
}
// This is a hack, I have to assume that there will never be more then 15 actions
- (void)action0:(id)sender { [self action:0]; }
- (void)action1:(id)sender { [self action:1]; }
- (void)action2:(id)sender { [self action:2]; }
- (void)action3:(id)sender { [self action:3]; }
- (void)action4:(id)sender { [self action:4]; }
- (void)action5:(id)sender { [self action:5]; }
- (void)action6:(id)sender { [self action:6]; }
- (void)action7:(id)sender { [self action:7]; }
- (void)action8:(id)sender { [self action:8]; }
- (void)action9:(id)sender { [self action:8]; }
- (void)action10:(id)sender { [self action:10]; }
- (void)action11:(id)sender { [self action:11]; }
- (void)action12:(id)sender { [self action:12]; }
- (void)action13:(id)sender { [self action:13]; }
- (void)action14:(id)sender { [self action:14]; }
That approach would work, although you need a unique selector-name for every button and a mapping from that name to whatever you want to target.
For the selector name a unique string has to be chosen (UUIDs or maybe a sanitized & prefixed version of the title would work). Then you need one method that resolves the call and "alias" it with the different selector names:
- (void)updateMenu:(NSArray *)menuEntries {
Class cls = [self class];
SEL fwd = #selector(forwarder:);
for (MenuEntry *entry in menuEntries) {
SEL sel = [self uniqueActionSelector];
// assuming keys not being retained, otherwise use NSValue:
[self.actionDict addObject:entry.url forKey:sel];
class_addMethod(cls, sel, [cls instanceMethodForSelector:fwd], "v#:#");
// now add menu item with sel as the action
}
}
Now the forwarder can look up what URL is associated with the menu item:
- (void)forwarder:(UIMenuController *)mc {
NSLog(#"URL for item is: %#", [actionDict objectForKey:_cmd]);
}
To generate the selectors you could use something like:
- (SEL)uniqueActionSelector {
NSString *unique = ...; // the unique part
NSString *selString = [NSString stringWithFormat:#"menu_%#:", unique];
SEL sel = sel_registerName([selString UTF8String]);
return sel;
}
Unless the menu items do the same thing, why should they share an action? I would go ahead and write actions that specify a behavior you want and link the menu items up to those.
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.
I'm new to Objective-C and need help!
I'm following the example "PageControl" which can be found on the net. I added a button to the view in the NIB and hooked up an action which the implementation is found below.
Here is my definition for the view controller being displayed in the page control:
//ContactCardViewController.h
#interface ContactCardViewController : UIViewController
{
int pageNumber;
NSMutableString *s;
}
//ContactCardViewController.m implementation
- (id)initWithPageNumber:(int)page {
if (self = [super initWithNibName:#"ContactCardViewController" bundle:nil]) {
s = [[NSString alloc] initWithFormat:#"page: %d", page];
}
return self;
}
- (id)initWithString:(NSDictionary *)_s {
if (self = [super initWithNibName:#"ContactCardViewController" bundle:nil]) {
NSMutableString *t = [[NSMutableString alloc] initWithString:_s];
s = t;
}
return self;
}
-(IBAction)callOrAddToContacts:(id)sender
{
jobtitleLabel.text = s;
}
//AppDelegate.m
//in delegate that loads the scroll view with the view for the current page:
- (void)loadScrollViewWithPage:(int)page {
//init the view this way the page: and the correct page number is displayed
controller = [[ContactCardViewController alloc] initWithPageNumber:page ];
//init the view this way, the value of the first person is always displayed
controller = [[ContactCardViewController alloc] initWithString:[[self.allNames objectAtIndex:page] objectForKey:#"firstname"]];
}
Please help me to understand why when the view is created with initWithString and then accessed via the button action only value for the first person in the list is always returned. When i init the view using initWithPageNumber s has the correct value Page: X.
In the InitWithString code, you're passing in a Dictionary, not a string.
- (id)initWithString:(NSDictionary *)_s {
if (self = [super initWithNibName:#"ContactCardViewController" bundle:nil]) {
NSMutableString *t = [[NSMutableString alloc] initWithString:_s];
s = t;
}
return self;
}
You may want to change that to NSString, or change the NSMutableString... to an instance of NSDictionary. One or the other.
Found out the problem was in the plist file. The code is fine.