Show activity indicator when iOS app is loading data? - ios

Question

My iPhone app has to load 3 data sets when it is first opened. I have 3 view controllers, one for each data set. I notice that when I am on my real iPhone and first open the app and touch a view controller there may be a very long pause, I am assuming while the data is being loaded, but I am not sure.
Here is the relevant code in my AppDelegate:
#import "AppDelegate.h"
#import "MasterViewController.h"
#implementation AppDelegate
- (void)application:(UIApplication *)application performFetchWithCompletionHandler: (void (^)(UIBackgroundFetchResult))completionHandler
{
// Background Fetch for Employees
EmployeeDatabase *tmpEmployeeDatabase = [[EmployeeDatabase alloc] init];
[tmpEmployeeDatabase updateEmployeeData];
completionHandler(UIBackgroundFetchResultNewData);
}
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Set Background Fetch Interval
[application setMinimumBackgroundFetchInterval: UIApplicationBackgroundFetchIntervalMinimum];
// Take Database Name and get DatabasePath for later use
self.databaseName = #"employees.db";
self.databaseNameLocations = #"locations.db";
self.databaseNameContacts = #"contacts.db";
NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentDir = [documentPaths objectAtIndex:0];
self.databasePath =[documentDir stringByAppendingPathComponent:self.databaseName];
self.databasePathLocations =[documentDir stringByAppendingPathComponent:self.databaseNameLocations];
self.databasePathContacts =[documentDir stringByAppendingPathComponent:self.databaseNameContacts];
// See if we need to initialize the employee db
EmployeeDatabase *tmpEmployeeDatabase = [[EmployeeDatabase alloc] init];
if (![tmpEmployeeDatabase checkIfDatabaseExists]) {
[tmpEmployeeDatabase updateEmployeeData];
}
// See if we need to initialize the contact db
ContactsDatabase *tmpContactsDatabase = [[ContactsDatabase alloc] init];
if (![tmpContactsDatabase checkIfDatabaseExists]) {
[tmpContactsDatabase updateContactsData];
}
// See if we need to initialize the Locations db
LocationDatabase *tmpLocationDatabase = [[LocationDatabase alloc] init];
if (![tmpLocationDatabase checkIfDatabaseExists]) {
[tmpLocationDatabase updateLocationData];
}
return YES;
}
#pragma mark - Application's Documents directory
// Returns the URL to the application's Documents directory.
- (NSURL *)applicationDocumentsDirectory {
return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}
#end
And here is where I call one of the web services and load the data:
#define kBgQueue dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)
- (void)callWebService {
AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
manager.requestSerializer = [AFJSONRequestSerializer serializer];
[manager.requestSerializer setAuthorizationHeaderFieldWithUsername:#"xxxxxx" password:#"xxxxxxxxxxxx"];
manager.responseSerializer = [AFJSONResponseSerializer serializer];
AFHTTPRequestOperation *operation = [manager GET: #"https://xxxx/mobile/mobilede.nsf/restPeople.xsp/People"
parameters: [self jsonDict]
success: ^(AFHTTPRequestOperation *operation, id responseObject)
{
NSMutableArray *employees = (NSMutableArray *)responseObject;
FMDatabase *db = [FMDatabase databaseWithPath:self.employeeDatabasePath];
[db open];
for (NSDictionary *dict in employees) {
BOOL success = [db
executeUpdate:
#"INSERT INTO employees "
"(id,fstNme,midNme,lstNme,fulNme,locNbr,supID,"
"mrkSeg,geoLoc,lvl,vp,ema,ofcPhn,mobPhn) VALUES "
"(?,?,?,?,?,?,?,?,?,?,?,?,?,?);",
[dict objectForKey:#"id"], [dict objectForKey:#"fstNme"],
[dict objectForKey:#"midNme"], [dict objectForKey:#"lstNme"],
[dict objectForKey:#"fulNme"], [dict objectForKey:#"locNbr"],
[dict objectForKey:#"supId"], [dict objectForKey:#"mrkSeg"],
[dict objectForKey:#"geoLoc"], [dict objectForKey:#"lvl"],
[dict objectForKey:#"vp"], [dict objectForKey:#"ema"],
[dict objectForKey:#"ofcPhn"],[dict objectForKey:#"mobPhn"], nil];
if (success) {
} // Only to remove success error
}
}
failure:
^(AFHTTPRequestOperation * operation, NSError * error) {
NSLog(#"Error: %#", error);
}
];
[operation start];
}
[EDIT]
I forgot the part of the code where I called the
[EDIT]
One possible mistake is that I am using the same background queue for each of the three processes? See the #define kBgQueue at the top of this bit of code.
What is the best practice to handle this? Should I NOT put this on a background queue and alert the user to wait?
[Thank you. I changed this and recompiled. The first time the app starts the interface will freeze at some point, and you cannot do anything for 12 seconds or so, and then it comes out of it. Subsequently there are no pauses. As an example, when I first open the app I can get to my first view, Employees by Name, and if I touch it to list them it might go into the the list but be blank. So I will touch the navigation backward and then it stops for 12 seconds (or so) and then it will return to the main menu, and when I go back in there are the employees. And it never stops from then on out. I cannot figure out why if this is on the background que that it is holding up the interface. What could I run to try to determine when this is happening?]

Answer 1

If your app could not work without data put data processing in background and show some activity indicator to user. If your app could work without data let user do whatever he wants to do and after data is being loaded just reload UI with new data.