I try to call a method after a delay when the user start to dragging a scrollView.
This block below is called but the action define in this performselector: is called only when I stop to drag the scrollView
- (void)viewDidLoad {
[super viewDidLoad];
UIScrollView *sv = [[UIScrollView alloc] initWithFrame:self.view.frame];
sv.delegate = self;
sv.backgroundColor = [UIColor redColor];
[sv setContentSize:CGSizeMake(1000, 200)];
[self.view addSubview:sv];
}
-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
NSLog(#"hey");
[self performSelector:#selector(myAction) withObject:nil afterDelay:3];
}
- (void)myAction
{
NSLog(#"Called 3secondes after begin dragging");
}
I also try with a NSTimer and in the background thread but the problem is the same...
Any Idea?
If you want to have the callback fired while you're still dragging, you must schedule it for Common Run Loop modes, like so:
[self performSelector:#selector(myAction) withObject:nil afterDelay:3 inModes:#[NSRunLoopCommonModes]];
That'll do the trick :)
Related
- (void)viewDidLoad {
[super viewDidLoad];
[self pingSplash];
UIViewController *next = [[self storyboard] instantiateViewControllerWithIdentifier:#"ViewController"];
[self.navigationController pushViewController:next animated:YES];
}
I mean to finish pinSplash then pushViewController, but it directly goto ViewController page, even without finishing pingSplash, what is a good way to do that kind of job?
For the pingSplash part:
- (void) pingSplash
{
SKSplashIcon *pingSplashIcon = [[SKSplashIcon alloc] initWithImage:[UIImage imageNamed:#"ping.png"] animationType:SKIconAnimationTypePing];
_splashView = [[SKSplashView alloc] initWithSplashIcon:pingSplashIcon backgroundColor:[UIColor grayColor] animationType:SKSplashAnimationTypeBounce];
_splashView.animationDuration = 5.0f;
[self.view addSubview:_splashView];
[_splashView startAnimation];
}
The pingSplash method returns as soon as it starts the animation which is why you end up pushing the view controller too soon.
There are a few ways to solve this. One way would be to pass a block to the pingSplash method that is run after an appropriate delay.
Here's one way:
Update the pingSplash method to take a completion handler block that is run after the 5 second delay.
- (void) pingSplash:(void (^)(void))completion
{
SKSplashIcon *pingSplashIcon = [[SKSplashIcon alloc] initWithImage:[UIImage imageNamed:#"ping.png"] animationType:SKIconAnimationTypePing];
_splashView = [[SKSplashView alloc] initWithSplashIcon:pingSplashIcon backgroundColor:[UIColor grayColor] animationType:SKSplashAnimationTypeBounce];
_splashView.animationDuration = 5.0f;
[self.view addSubview:_splashView];
[_splashView startAnimation];
if (completion) {
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(_splashView.animationDuration * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
completion();
});
}
}
Then update your viewDidLoad:
- (void)viewDidLoad {
[super viewDidLoad];
[self pingSplash:^{
UIViewController *next = [[self storyboard] instantiateViewControllerWithIdentifier:#"ViewController"];
[self.navigationController pushViewController:next animated:YES];
}];
}
I have an application with UIScrollView added as a subview of UIView. i have added UITextField,UITextview as a subView of UIScrollView .I want to dismiss the keyboard when i tap in the scroll view. how can i do this?
Just add UITapGestureRecognizer
- (void)viewDidLoad
{
[super viewDidLoad];
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(singleTapGestureCaptured:)];
[scr addGestureRecognizer:singleTap];
}
- (void)singleTapGestureCaptured:(UITapGestureRecognizer *)gesture
{
//Get touch point
CGPoint touchPoint=[gesture locationInView:scr];
//Hide keyBoard
[self.view endEditing:YES];
}
In iOS 7, you can achieve this easily.
scrollView.keyboardDismissMode = UIScrollViewKeyboardDismissModeInteractive;
Try this,
- (void)viewDidLoad
{
[super viewDidLoad];
UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(dismissKeyboard)];
tapGesture.cancelsTouchesInView = NO;
[scrollView addGestureRecognizer:tapGesture];
[tapGesture release];
}
-(void)dismissKeyboard
{
[txtNotes resignFirstResponder];
[textView resignFirstResponder];
}
When I added the gesture to a subclass of UIScrollView, I was having problems with the various gestures in my view tree interfering with each other, such as being able to click on subviews, scroll the view, and have the keyboard dismiss in all cases. I came up with this solution, which can be setup from a superclass of UIScrollView or from a UIViewController.
The DismissKeyboardTapGesture class uses ARC, works with any text fields under the view, and doesn't take over any clicks from subviews like buttons. Also takes advantage of iOS7 scrolling effect to dismiss keyboard.
Setting up from UISScrollView superclass:
_dismissKeyboard = [[DismissKeyboardTapGesture alloc] initWithView:self];
or from UIViewController:
_dismissKeyboard = [[DismissKeyboardTapGesture alloc] initWithView:self.view];
Here is the class:
#interface DismissKeyboardTapGesture : NSObject <UIGestureRecognizerDelegate>
#end
#implementation DismissKeyboardTapGesture
- (id)initWithView:(UIView *)view
{
self = [super init];
if (self) {
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(singleTap:)];
singleTap.cancelsTouchesInView = NO;
singleTap.delegate = self;
[view addGestureRecognizer:singleTap];
if ([view respondsToSelector:#selector(setKeyboardDismissMode:)]) {
// Bonus effect to dismiss keyboard by scrolling
((UIScrollView *)view).keyboardDismissMode = UIScrollViewKeyboardDismissModeInteractive;
}
}
return self;
}
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
// Don't stop any existing gestures in our view from working
if (otherGestureRecognizer.view == gestureRecognizer.view) {
return YES;
}
return NO;
}
- (void)singleTap:(UIGestureRecognizer*)gestureRecognizer
{
// Close keyboard for any text edit views that are children of the main view
[gestureRecognizer.view endEditing:YES];
}
#end
I've been trying to figure this out for 2 days now, and before anyone posts another stackoverflow question, I've read them all and none of them cover my problem exactly:
I have a CoreData app that updates dynamically. Now during the update I want an UIAlertView to pop up saying that an update is being downloaded.
So here's the important code:
AppDelegate:
- (void)applicationDidBecomeActive:(UIApplication *)application
{
[myUpdater checkForUpdatesInContext:self.managedObjectContext];
}
_
Updater Class:
- (void)checkForUpdatesInContext:(NSManagedObjectContext *)myManagedObjectContext
{
[self loadUpdateTime];
NSLog(#"Update start");
NSDate *now = [NSDate dateWithTimeIntervalSinceNow:[[NSTimeZone localTimeZone] secondsFromGMT]];
if ([now timeIntervalSinceDate:updateTime] < UPDATE_TIME_INTERVAL)
{
return;
}
[self showAlertViewWithTitle:#"Update"];
... //updating process
[self.alertView dismissWithClickedButtonIndex:0 animated:YES];
NSLog (#"Update done");
}
- (void) showAlertViewWithTitle:(NSString *)title
{
self.alertView = [[UIAlertView alloc] initWithTitle:title message:#"Daten werden aktualisiert..." delegate:self cancelButtonTitle:nil otherButtonTitles:nil];
... //design the alertView
[self.alertView show];
NSLog (#"AlertView shows");
}
So here is what happens when I run this:
Launch image shows
NSLog "Update starts" fires
NSLog "AlertView shows" fires
Screen dims but no AlertView is shown
Update is running
NSLog "Update done" fires
Launch image goes away and TabBarController shows up
UIAlertView shows up and is dismissed right away and the dimmed screen returns to normal
What I would like to have happen:
Launch image
TabBarController shows up
Screen dims and UIAlertView shows
Update is running
UIAlertView gets dismissed and dimmed screen returns to normal
I know it's something with the UI Thread and the main Thread and stuff.. But I tried every combination it seems but still not the expected result. Please help :)
EDIT:
HighlightsViewController Class:
- (void)viewDidLoad
{
[super viewDidLoad];
self.updater = [[Updater alloc] init];
[updater checkForUpdatesInContext:self.managedObjectContext];
... // other setup stuff nothing worth mentioning
}
Is this the right place to call [super viewDidLoad]? Because it still doesn't work like this, still the update is being done while the Launch Image is showing on the screen. :-(( I'm about to give this one up..
Here you go, in this prototype things work exactly how you want them to.
Header:
#import <UIKit/UIKit.h>
#interface AlertViewProtoViewController : UIViewController
{
}
- (void) showAlertViewWithTitle:(NSString *)title;
- (void) checkForUpdatesInContext;
- (void) update;
- (void)someMethod;
- (void)someOtherMethod;
#end
#import "AlertViewProtoViewController.h"
Class:
#implementation AlertViewProtoViewController
UIAlertView *alertView;
bool updateDone;
UILabel *test;
bool timershizzle;
#pragma mark - View lifecycle
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.view.backgroundColor = [UIColor yellowColor];
UILabel *test = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
test.backgroundColor = [UIColor blueColor];
[self.view addSubview:test];
[self performSelector:#selector(checkForUpdatesInContext) withObject:nil afterDelay:0.0];
}
- (void)update
{
//NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; //commented for auto ref counting
NSLog(#"update start");
//your update stuff
NSLog(#"update end");
updateDone = YES;
//[pool release];
}
- (void)checkForUpdatesInContext//:(NSManagedObjectContext *)myManagedObjectContext
{
//[self loadUpdateTime];
NSLog(#"Update start");
NSDate *now = [NSDate dateWithTimeIntervalSinceNow:[[NSTimeZone localTimeZone] secondsFromGMT]];
// if ([now timeIntervalSinceDate:updateTime] < UPDATE_TIME_INTERVAL)
// {
// return;
// }
[self showAlertViewWithTitle:#"Update"];
//[self setManagedObjectContext:myManagedObjectContext];
[self performSelector:#selector(someMethod) withObject:nil afterDelay:0.0];
[self performSelector:#selector(someOtherMethod) withObject:nil afterDelay:0.0];
}
-(void)someOtherMethod
{
while (!updateDone) {
// NSLog(#"waiting...");
}
[alertView dismissWithClickedButtonIndex:0 animated:YES];
NSLog (#"Update done");
self.view.backgroundColor = [UIColor greenColor];
}
-(void)someMethod
{
[self performSelectorInBackground:#selector(update) withObject:nil];
}
- (void) showAlertViewWithTitle:(NSString *)title
{
alertView = [[UIAlertView alloc] initWithTitle:title message:#"Daten werden aktualisiert..." delegate:self cancelButtonTitle:nil otherButtonTitles:nil];
alertView.frame = CGRectMake(100, 100, 200, 200);
alertView.backgroundColor = [UIColor whiteColor];
[self.view addSubview:alertView];
[self.view setNeedsDisplay];
NSLog (#"AlertView shows");
}
#end
You should adjust were needed for your own purposes but it works.
You are starting a background thread and then dismissing the alert immediately. I would suggest that you might use an NSNotification, posted from the background task, and received in whichever controller starts the alert, triggering a method that dismissed the alert.
I find the UIAlertView interface unsuitable for this type of user notice, and prefer to use a semi-transparent overlay view with a UIActivityIndicatorView, plus an informing message for the user.
You are doing a:
- (void)applicationDidBecomeActive:(UIApplication *)application
Isn't it so that the alertview you want to show needs a view to be loaded which isn't active yet at this point? See: http://developer.apple.com/library/ios/#documentation/uikit/reference/UIAlertView_Class/UIAlertView/UIAlertView.html
Similar question? UIAlertView starts to show, screen dims, but it doesn't pop up until it's too late!
So, another EXC_BAD_ACCESS topic on StackOverflow, but as I'm new to Objective-C this is still a topic I don't really grasp yet. Even though I have done a lot of research about it already.
The issue is the following. I have a UIScrollView that I have overwritten using a Custom Class (named MultiSelectView). If the user taps this UIScrollView and then I want to open a view that allows him to select some data.
So I have declared a UITapGestureRecognizer that calls the openMultiSelect: method. But on the line [parent.navigationController pushViewController:view animated:YES]; I get a Program received signal: "EXC_BAD_ACCESS". error. Why o why?
- (id) initWithCoder:(NSCoder *) coder {
self = [super initWithCoder: coder];
if (self) {
// Add a Tap Gesture Recognizer to the Scrollview.
// If the user taps the view, it triggers the 'openMultiSelect' method.
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(openMultiSelect:)];
[singleTap setNumberOfTapsRequired:1];
[singleTap setNumberOfTouchesRequired:1];
[self addGestureRecognizer:singleTap];
}
return self;
}
- (void)openMultiSelect:(UIGestureRecognizer *)gesture {
//int myViewTag = gesture.view.tag; // now you know which view called
DataSelectView *view = [[DataSelectView alloc] initWithNibName:#"DataSelectView" bundle:[NSBundle mainBundle]];
view.allowMultiSelect = YES;
[parent.navigationController pushViewController:view animated:YES];
[view release];
}
So the parent that you see is a ViewController that contains the tab. Is there a better way to do this? Because for now I have thus a ViewController that contains Tabs. In its activateTab: method I thus create the tab and pass self along. I do the same in the viewDidLoad for that tab to pass the parent to the custom UIScrollView:
- (void) activateTab:(int)index {
... code ...
self.tab_Basic = [[TabBasic alloc] initWithNibName:#"TabBasic" bundle: [NSBundle mainBundle]];
self.tab_Basic.parent = self;
... code ...
}
You should make some change to your callback method. Something like that:
- (void)openMultiSelect:(UIGestureRecognizer *)gesture {
//int myViewTag = gesture.view.tag; // now you know which view called
if(gesture.state == UIGestureRecognizerStateEnded){
DataSelectView *view = [[DataSelectView alloc] initWithNibName:#"DataSelectView" bundle:[NSBundle mainBundle]];
view.allowMultiSelect = YES;
[parent.navigationController pushViewController:view animated:YES];
[view release];
}
}
What you are doing wrong is releasing the object "view" too early, don't release it until the view is popped. That should fix the problem.
- (void)openMultiSelect:(UIGestureRecognizer *)gesture {
//int myViewTag = gesture.view.tag; // now you know which view called
DataSelectView *view = [[DataSelectView alloc] initWithNibName:#"DataSelectView" bundle:[NSBundle mainBundle]];
view.allowMultiSelect = YES;
[parent.navigationController pushViewController:view animated:YES];
I have a UIViewController that contains a UIView.
Between every time the viewcontroller is displyaed, the UIView has to be cleared and the content reloaded.
The problem is that the old content still appears in the UIView.
Load data before controller becomes visible:
- (void)viewWillAppear:(BOOL)animated
{
contentView = [[ContentView alloc] initWithFrame:CGRectMake(10, 10, 100, 100)];
contentView.userInteractionEnabled = NO;
[self.view addSubview:contentView];
if([self loadContentData] == NO) {
[contentView release];
return NO;
}
return YES;
}
Remove content after controller is hidden:
- (void)viewDidDisappear:(BOOL)animated
{
[contentView removeFromSuperview];
[contentView release];
}
Why is this cleanup not sufficient?
Try:
- (void)viewDidDisappear:(BOOL)animated
{
[super viewDidDisappear:animated];
[contentView removeFromSuperView]; //releases contentView
}
You must call super's method when overriding this method.
Additionally, contentView appears to be over-released in the code you've posted which makes me believe you are retaining it possibly somewhere in your real code. If this is the case, you may have over-retained contentView, which will prevent it from being released and cleaned up from your view hierarchy.
I would suggest you explore something along these lines:
- (void)viewWillAppear:(BOOL)animated
{
contentView = [[[ContentView alloc] initWithFrame:CGRectMake(10, 10, 100, 100)] autorelease];
contentView.userInteractionEnabled = NO;
[self.view addSubview:contentView];
if([self loadContentData] == NO) {
//[contentView release]; //ContentView is now autoreleased and will be dropped when the method exits.
return NO; //this probably has a compiler warning, since it is a (void) method
}
return YES; //this probably has a compiler warning, since it is a (void) method
}