An App interface has an UISegmentedControl on the top of screen and a UITableView of the rest of the screen.
When UiSegmentedControl gets a click then NSFetchedController gets an update for NSPredicate of NSFetchRequest and perform a performFetch method.
Because, it's take a 4 seconds to take a result I would like to reload a tableview to display 0 sections and after the result is ready then reload a tableView.
how to do it ?
- (void)viewDidLoad
{
[super viewDidLoad];
[self performSelectorInBackground:#selector(exercisedata) withObject:nil];
}
-(void)exercisedata
{
[self performSelectorOnMainThread:#selector(ProcessComplete) withObject:nil waitUntilDone:NO];
}
-(void)ProcessComplete
{
[tbl reloadData];
}
Related
Usually after the viewController is pushed, I want to do certain things. In add phone feature, for example, I would open edit business and set the focus to the phone field.
If after viewController is pushed users press back button too quickly the app crash.
What's the standard way to do so?
This is the code:
+(BGBusinessEditViewController *) pushNewEditViewControllerWithBizandReturnValue: (Business *)biz withNavController :(UINavigationController *) nav andSelectPhone:(BOOL) selectPhoneAfterward
{
BGBusinessEditViewController * editBusiness = [[BGBusinessEditViewController alloc]init];
//[editBusiness view];//load the stuff first
[nav vPushViewController:editBusiness animated:YES andPerformBlock:^{
if (biz) {
editBusiness.biz=biz; //viewDidload must be called first before setting bizs
}
if (selectPhoneAfterward)
{
[editBusiness selectPhone];
}
}];
return editBusiness;
}
-(void) selectPhone
{
NSIndexPath * ipth =[NSIndexPath indexPathForItem:BGBusinessEditTextPhoneNumber inSection:0];
[self.tableView selectRowAtIndexPath: ipth animated:NO scrollPosition:UITableViewScrollPositionTop];
[self tableView:self.tableView didSelectRowAtIndexPath:ipth];
}
Basically I created a category in nav View Controller that will run code only when the navigation controller already reach - (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated;
Well, Hide the back button until viewDidAppear, and then unhide it.
I have a UITableView and when I touch a row of its I call myFunction that perform any operation and then reload the table.
Now I want to show an UIActivityIndicator while I call myFunction. What is the approach followed in these cases?
This is my code:
-(void)collectionView:(UICollectionView*)collectionview didSelectItemAtIndexPath:(NSIndexPath*) indexPath {
[self showLoader];
[self performSelectorInBackground:#selector(myFunction:) withObject:indexPath];
[self hideLoader];
}
I prefer to use this MBProgressHUD.
This is good example for calling UIActivityIndicator while loading data.
Add some Delay in your Call :
-(void)collectionView:(UICollectionView*)collectionview didSelectItemAtIndexPath:(NSIndexPath*) indexPath
{
[self showLoader];
[self performSelector:#selector(myFunction:) withObject:indexPath afterDelay:1.0];
[self hideLoader];
}
GoodLuck...!!!
In This code UIActivityIndicator display in statusBar
-(void)collectionView:(UICollectionView*)collectionview didSelectItemAtIndexPath:(NSIndexPath*) indexPath {
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
[self showLoader];
[self performSelector:#selector(myFunction:) withObject:indexPath afterDelay:1.0];
[self hideLoader];
}
and for stop UIActivityIndicator write following code at end of myFunction
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
I have an app that uses the UITabBarController and one of the tabs is supposed to be a full on camera view (similar to Instagram). When I launch the app and go to that view, most of the screen is blank and no image library picker/camera view loads. Any help would be greatly appreciated.
Here is my viewDidLoad method:
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
imagePicker = [[UIImagePickerController alloc] init];
if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
[imagePicker setSourceType:UIImagePickerControllerSourceTypeCamera];
} else {
[imagePicker setSourceType:UIImagePickerControllerSourceTypePhotoLibrary];
}
[imagePicker setDelegate:self];
[imagePicker setEditing:NO];
// Place image picker (camera viewing angle on the screen)
[self presentViewController:imagePicker animated:YES completion:nil];
}
Try putting that code in viewDidAppear instead -- that worked for me. Better yet, would be to put all but the last line in viewDidLoad, so it's only called once, and just put the last line in the viewDidAppear method. When you cancel the image picker (the only thing I tested), it will just reappear, since viewDidAppear will be called again, so you need to implement imagePickerControllerDidCancel: like this to keep that from happening:
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {
[self dismissViewControllerAnimated:YES completion:nil];
self.imagePicker = nil;
}
And, in your viewDidAppear, put in an if statement to see if the picker exists before trying to present it:
if (self.imagePicker) {
[self presentViewController:self.imagePicker animated:YES completion:nil];
}
I have a tabbar application, the problem is that i need to call a method after a delay of viewDidLoad of the first view but it didn't work (the method is not called)
i added the following sample
- (void)viewDidLoad
{
[super viewDidLoad];
[self performSelector:#selector(foo) withObject:nil afterDelay:1];
}
-(void)foo
{
NSLog(#"foo!");
}
the strange thing is that this work with all other tabs view but for some reason it didn't work with the first tab (UITableViewController)
any idea??
Thanks
try this....
- (void)viewDidLoad
{
[super viewDidLoad];
dispatch_async(dispatch_get_main_queue(), ^{
[self performSelector:#selector(foo) withObject:nil afterDelay:0.5];
});
}
when i click on button which title is click here to enlarge then i want show activity indicator on the first view and remove when load this view.
but i go back then it show activity indicator which is shown in this view.
in first vie .m file i have use this code for action.
-(IBAction)btnSelected:(id)sender{
UIButton *button = (UIButton *)sender;
int whichButton = button.tag;
NSLog(#"Current TAG: %i", whichButton);
UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
[spinner setCenter:CGPointMake(160,124)];
[self.view addSubview:spinner];
[spinner startAnimating];
if(whichButton==1)
{
[spinner stopAnimating];
first=[[FirstImage alloc]init];
[self.navigationController pushViewController:first animated:YES];
[spinner hidesWhenStopped ];
}}
in above code i have button action in which i call next view. Now i want show/display activity indicator when view upload. In next view i have a image view in which a image i upload i have declare an activity indicator which also not working. How do that?
Toro's suggestion offers a great explanation and solution, but I just wanted to offer up another way of achieving this, as this is how I do it.
As Toro said,
- (void) someFunction
{
[activityIndicator startAnimation];
// do computations ....
[activityIndicator stopAnimation];
}
The above code will not work because you do not give the UI time to update when you include the activityIndicator in your currently running function. So what I and many others do is break it up into a separate thread like so:
- (void) yourMainFunction {
activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
[NSThread detachNewThreadSelector:#selector(threadStartAnimating) toTarget:self withObject:nil];
//Your computations
[activityIndicator stopAnimating];
}
- (void) threadStartAnimating {
[activityIndicator startAnimating];
}
Good luck!
-Karoly
[self.navigationController pushViewController:first animated:YES];
Generally, when you push a view controller into navigation controller, it will invoke the -(void)viewWillAppear: and -(void)viewDidAppear: methods. You can add activity indicator view inside the viewWillAppear: and call startAnimation of indicator view. You CANNOT invoke startAnimation and stopAnimation at the same time. For example,
- (void)viewWillAppear:(BOOL)animated
{
[aIndicatorView startAnimation];
// do somethings ....
[aIndicatorView stopAnimation];
}
Because the startAnimation and stopAnimation are under the same time, then no animation will show.
But if you invoke startAnimation in -(void)viewWillAppear: and invoke stopAnimation in another message, like followings.
- (void)viewWillAppear:(BOOL)animated
{
[aIndicatorView startAnimation];
// do somethings...
}
- (void)viewDidAppear:(BOOL)animated
{
[aIndicatorView stopAnimation];
}
Because viewWillAppear: and viewDidAppear: are invoked with different event time, the activity indicator view will work well.
Or, you can do something like followings:
- (void)viewWillAppear:(BOOL)animated
{
[aIndicatorView startAnimation];
// Let run loop has chances to animations, others events in run loop queue, and ... etc.
[[NSRunLoop currentRunLoop] runUntilDate:[NSDate date]];
// do somethings ....
[aIndicatorView stopAnimation];
}
The above example is a bad example, because it invokes two or more animations in the -runUntilDate:. But it will let the activity indicator view work.
Create a webview. Add a activity indicator to the webview. If you are loading a image via url into the webview then implement the webview delegate methods. Once the url is loaded then stopanimating the activity indicator.
Let me know which step you are not able to implement.