What is a good concept to implement activity indicator - ios

In our iPgone & iPad app we use push segue transitions between different ui contollers, most of them extend UICollectionViewController. In each controller we load data from our internal API. Loading is done viewWillAppear or viewDidLoad.
Now, the thing is, that this API call sometime can take a second or two, or even three... well, lot's of stuff there, let's assume we can't change it. But, we can change the user experience and at least add the "loading" circle indicator. The thing is, what I can't understand by means of correct concept, while transition from A to B, the "load" is done at B, while page A still presented.
So, question is "how do I show indicator on page A, while loading controller for page B?"
Thanks all,
Uri.

Common approach in this case is to load data in destination view controller NOT in main thread. You can show indicator while loading data in background thread and then remove it.
Here is sample of code from my project solving the same problem:
- (void) viewDidLoad {
...
// add indicator
self.spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
self.spinner.hidesWhenStopped = YES;
self.spinner.center = self.view.center;
[self.view addSubview:self.spinner];
...
// fetch news
[self.spinner startAnimating];
__weak typeof(self) weakSelf = self
[[BitrixApiClient sharedInstance] getLatestNewsWithCompletionBlock:^(NSArray *newsArray, NSUInteger maxPageCount, NSUInteger currentPageNumber, NSError *error) {
if (!error) {
weakSelf.newsArray = newsArray;
weakSelf.currentPageNumber = currentPageNumber;
[weakSelf.newsTableView reloadData];
}
// stop spinning
[weakSelf.spinner stopAnimating];
}];
}

Related

iOS - Show SVProgressHUD message on screen without interrupting user interaction

I'm making a synchronize function that syncs local Core Data with the server. I want to make the synchronizations happen in the background without disrupting user interaction. When I receive the response (whether success or failure) the app should display a message somewhere on the screen to notify the user about the outcome.
UIAlertController is not a good choice because it will block user action.
Currently I'm using SVProgressHUD:
__weak StampCollectiblesMainViewController *weakSelf = self;
if ([[AppDelegate sharedAppDelegate] hasInternetConnectionWarnIfNoConnection:YES]) {
[_activityIndicator startAnimating];
[Stamp API_getStampsOnCompletion:^(BOOL success, NSError *error) {
if (error) {
[_activityIndicator stopAnimating];
[SVProgressHUD setDefaultMaskType:SVProgressHUDMaskTypeClear];
[SVProgressHUD setAnimationDuration:0.5];
[SVProgressHUD showErrorWithStatus:#"error syncronize with server"];
}
else {
[_activityIndicator stopAnimating];
[featuredImageView setImageWithURL:[NSURL URLWithString:[Stamp featuredStamp].coverImage] usingActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
[yearDropDownList setValues:[Stamp yearsDropDownValues]];
[yearDropDownList selectRow:0 animated:NO];
[weakSelf yearDropDownListSelected];
[SVProgressHUD dismiss];
}
}];
}
Is there a modification I can make so the user can still interact with the app? I just want to show the message without taking up too much space. Any help is much appreciated. Thanks.
Looks like the easiest thing will be to use SVProgressHUDMaskTypeNone.
Also check out this issue.
Sorry but you gonna have to build your own custom view.
In fact it's not that difficult. What I would do is simply add a small view on the top of the screen with your custom message and a close button (to allow user to hide quickly the message). This is usually done by adding this new view to the current window, so that it will be on the top of every view and won't block the UI (except the part hidden by that view :) )

Move to next UIViewcontroller, while data to be displayed there, is still loading

I am writing an ios app, that has multiple UIViewcontrollers. They all have UITableViews that are filled with data, that is acquired from different API's. But the problem that I am facing is that, when I tap on a cell, the the app won't navigate to the next page, until the data for that page is acquired. This make the app look, mighty slow. I need some way to navigate to next page, where I can put some spinner animation to let the user know that it is acquiring data(atleast). I don't want the user to think that the app has crashed, or something(it stays in the same page for solid 7-10 seconds)
Thanks in advance
you should call all the api in the background so it wont effect the main thread, use the queue for call api in background queue like below.
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0);
dispatch_async(queue, ^{
//call apis here
});
My solution to this problem is,You can call the API using dispatch queue,So that it will not affect other functionalities.
Please follow these simple steps
ViewController1 = VC1
ViewController1 = VC2
in VC1
[self.navigationController pushViewController:VC2 animated:YES];
in VC2
#implementation {
BOOL hasData;
}
-(void)viewDidLoad {
hasData = NO;
[self getAndShowData];
}
-(void)getAndShowData {
// Start Showing Spinner
// load your data from server and
// on success
1.) hasData = YES;
2.) Call reload tableview
// Remove spinner
}
- (NSInteger)numberOfRowsInSection:(NSInteger)section {
if(hasData == NO) return 0;
return actual number of rows.
}
}

MBProgressHUD has a chunk taken out of the middle?

I'm examining some code written by someone else, as part of a new job I've been hired for. One of the bugs confronting me is that, on certain pages, when the MBProgressHUD is displayed for "Logging In" or "Connecting," it gets a chunk taken out of the middle. For example:
Obviously what I'm looking for is something a little more like this:
It only seems to happen when the app returns from the background (i.e. not when the app is first booting up, when we also use MBProgressHUD but it works perfectly), and only on certain pages. The box loads correctly, and then about half a turn of the Activity Indicator later, that hole appears. It then stays like that until the box disappears.
I'd add some code to look at, but to be perfectly honest, I don't know where to start. I can't think of anything that could take a chunk out of the middle like that, and as you can see from the transparency of the second picture, there doesn't seem to be a box of that shape/size behind the Activity Indicator that could be accidentally turning green.
I've never used MBProgressHUD myself before, and I've never encountered a graphical bug of this nature. Does anyone know what is going on, or failing that, can anyone give me some leads to investigate regarding what could be causing this behavior?
EDIT:
Below is the code used to add the Activity Indicator to the HUD (from within the MBProgressHUD object):
// Update to indeterminate indicator
[self.indicator removeFromSuperview];
self.indicator = nil;
if (IOSVersion >= 8.0 && (DeviceScreenSize().height >= 1136.0 || DeviceScreenSize().width >= 1136.0)) {
self.indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
} else {
self.indicator = MB_AUTORELEASE([[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge]);
}
[(UIActivityIndicatorView *)indicator startAnimating];
[self addSubview:indicator];
This is part of a larger updateIndicators method, but the salient points are there: the indicator is removed (in case there was another there before), then it is re-added and animated. Comment out either of the startAnimating or addSubview lines, and the HUD appears without the Activity Indicator, but the problem never occurs.
That sounds to me like the animation of the Activity Indicator is somehow causing the missing piece of the underlying view. But why would that be? Has anyone heard of that kind of thing before?
EDIT 2:
As far as I can tell, the problem only happens on one ViewController in the whole app, and yet that ViewController never references MBProgressHUD or Activity Indicators of any kind. And all of that functionality is in the AppDelegate method applicationDidBecomeActive:, as below:
MBProgressHUD* hud = [[MBProgressHUD alloc] initWithWindow:self.window];
[self.window addSubview:hud];
hud.labelText = LocalizedString(#"Logging in...");
[hud showAnimated:YES whileExecutingBlock:^{
User* U = self.SelectedUser;
if (!isEmpty(U)) {
if ([U networkLogin]) {
[self setSelectedUser:U];
if ([U Disabled] != disabledTypesNone) {
[Flurry logEvent:#"Login Failed" withParameters:#{#"Name": U.DisplayName,
#"DeviceID": [#([Device sharedDevice].DeviceID) stringValue],
#"Disabled": [#([U Disabled]) stringValue]}];
ret = NO;
} else {
[Flurry logEvent:#"Login" withParameters:#{#"Name": U.DisplayName,
#"DeviceID": [#([Device sharedDevice].DeviceID) stringValue]}];
[Flurry setUserID:[NSString stringWithFormat:#"%# - %#", U.EmpID, U.DisplayName]];
}
} else {
ret = NO;
}
}
} completionBlock:^{
[hud removeFromSuperview];
if (!ret) {
[[NSNotificationCenter defaultCenter] postNotificationName:kDisplayLogin object:nil];
} else {
[[NSNotificationCenter defaultCenter] postNotificationName:kLoggedIn object:nil];
}
}];
Since it's happening in AppDelegate, it ought to be the same throughout the app, correct? And yet, when that same code is called (from AppDelegate, as before) while the app is on a different ViewController, it works with no problems.
What might make the behavior of that method different between different ViewControllers?

UIActivityIndicatorView not rendering

I have an app that makes web service calls to obtain data. I want to add an activity indicator that is visible when the app is fetching web service data. I have looked into other posts, and though I believe I am doing as the posts recommend, my indicator does not render on the screen. The object that makes the web service call is stateGauges. Here is my code:
- (void)viewDidLoad
{
[super viewDidLoad];
UIActivityIndicatorView *activityStatus = [[UIActivityIndicatorView alloc] initWithFrame:CGRectMake(120, 230, 50, 50)];
activityStatus.center = self.view.center;
[self.view addSubview:activityStatus];
[activityStatus bringSubviewToFront:self.view];
[UIApplication sharedApplication].networkActivityIndicatorVisible = TRUE;
[activityStatus startAnimating];
stateGauges = [[GaugeList alloc] initWithStateIdentifier:stateIdentifier andType:nil];
[activityStatus stopAnimating];
}
Any suggestions? Thanks! V
Your problem is that your animation start is blocked by whatever you're doing in your GuagesList initializer.
When you tell the activity indicator to start animating, it doesn't immediately render to the screen but rather flags the view as needing an update on the next turn of the run loop. Your initializer then blocks the thread until its done, you call stopAnimating, and then the thread has a chance to update the indicator. By which point its already set to not animate.
The best solution is to perform your initializer on another thread using GCD. And be sure to switch back to the foreground thread before calling stopAnimating.
The usual pattern is do something like:
[activityStatus startAnimating];
// enqueue it
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
stateGauges = [[GaugeList alloc] initWithStateIdentifier:stateIdentifier andType:nil];
// now switch back to main thread
dispatch_async(dispatch_get_main_queue(), ^{
[activityStatus stopAnimating];
});
});
You'll want to verify the code as I had to type this from memory on a Windows machine.
take out
[activityStatus bringSubviewToFront:self.view];
because according to the docs bringSubviewToFront:
Moves the specified subview so that it appears on top of its siblings.
which isn't what you want. (another answer suggested you do [self.view bringSubviewToFront:activityStatus] instead.. that's fine, but generally this call is redundant, b/c
[self.view addSubview:activityStatus] adds the activityStatus to the end of the views in the self.view subviews array anyways)
if that still don't work.. basically put a break point right after you start animating, then type this into the console:
[[activityStatus superview] recursiveDescription]
recursiveDescription will give you a UI tree graph and basically tell you exactly where the activityIndicator view is.. you may have made an incorrect assumption about something.
Change
[activityStatus bringSubviewToFront:self.view];
To
[self.view bringSubviewToFront:activityStatus];

IOS,when an UIView get fully loaded

I have an PlayPageViewController as rootViewController. The PlayPageViewController will display 3D models and UIImages in an method call editPages(), which will takes several seconds to wait.
I just want to add an loadingView at start and when PlayPageViewController gets fully loaded it will disappear.
Here is my solution:
Add an loadingView with activityIndicator.
When the loadingView is loaded, I will begin to implement
but seems it didn't work
STLoadingViewController *loadingView =
[[STLoadingViewController alloc]initWithNibName:#"STLoadingViewController"
bundle:nil];
loadingView.view.frame=CGRectMake(0, 0, 1024, 768);
[self.view insertSubview:loadingView.view atIndex:3];
if(loadingView.isViewLoaded && loadingView.view.window)
{
[self.view insertSubview:self.playPageViewController.view atIndex:4];
[self.playPageViewController setEditingPage:pageIndex];
[loadingView.view removeFromSuperview];
}
You have to do your respective methods to call in viewDidAppear method when this method is called all the appearing task had been finished.
What is the ViewLoad() method? Do you mean viewDidLoad:? You could setup all your views in the storyboard, including a view containing the activity indicator. Don't load the model at this point but wait until viewDidLoad: is called. At this point you may use Grand Central Dispatch to start the loading of the model. It could look a bit like this:
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
// You need to setup the activity indicator outlet in the storyboard
[_activityIndicator startAnimating];
}
- (void)viewDidLoad {
[super viewDidLoad];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
// Do the expensive work on the background
[NSThread sleepForTimeInterval:5.0f];
// All UI related operations must be performed on the main thread!
dispatch_async(dispatch_get_main_queue(), ^{\
// Replace the view containing the activity indicator with the view of your model.
[_activityIndicator stopAnimating];
NSLog(#"STOP");
});
});
}
Edit: The link seems to be down. This is probably due to the current problems with the Dev Center. You can find the documentation in the documentation pane of the Xcode Organizer.

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