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AGSGDBFeatureServiceTable load in background thread

SimonFox

Hi folks,

I'm tearing my hair out trying to load a feature service table in a background thread, as below. This works fine on the main iOS thread. But in a background thread no network activity occurs. I confirmed using Charles proxy server.

Hard to understand why, as it appears to block the main thread. My app locks up while these calls are occurring. Have I missed something?

Thanks,
Simon

dispatch_queue_t backgroundLoadThread = dispatch_queue_create("com.xyz.loadservicethread", NULL);

dispatch_async(backgroundLoadThread, ^(void) {

AGSGDBFeatureServiceTable* fst = [[AGSGDBFeatureServiceTable alloc]initWithServiceURL:url

credential:myCredentials

spatialReference:mapView.spatialReference];

...

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SimonFox

using loadCompleted(...) doesn't help either.

DiveshGoyal

The feature service table, like other classes in the SDK that connect to web services, already performs its loading on a background thread, even if you instantiate it on the main thread. Is there a reason why you still want to create it on a background thread?

SimonFox

Hi Divesh, thanks for your reply.

It appeared to me that the call was being made on the main thread. With the debugger it can take some seconds to proceed across the initWithServiceURL call.

It's possible that the lag is occurring somewhere else I guess. It's not apparent in my own code though, so at some point there are long delays occurring on the main thread and my UI is freezing for 15 seconds or so.

Which operation exactly is freezing, I guess I can't be sure. Perhaps it is the post-processing of loaded data after the call is complete. But there doesn't seem to be any way to keep the main thread free during this loading.

Regards,

Simon.

SimonFox

This is the code block that causes the app to freeze up. Maybe will help see where my problem lies.

Thanks for any help, much appreciated.

self.geodatabaseTask.loadCompletion = ^(NSError* error) {

for (AGSMapServiceLayerInfo* info in self.geodatabaseTask.featureServiceInfo.layerInfos) {

NSURL* url = [self.geodatabaseTask.URL URLByAppendingPathComponent:[NSString stringWithFormat:@%lu,(unsigned long)info.layerId]];

AGSGDBFeatureServiceTable* fst = [[AGSGDBFeatureServiceTable alloc]initWithServiceURL:url

credential:self.credentials

spatialReference:mapView.spatialReference];

AGSFeatureTableLayer *f = [[AGSFeatureTableLayer alloc]initWithFeatureTable:fst];

f.delegate = self;

fst.loadCompletion = ^(NSError* error) {

[mapView addMapLayer:f];

};

}

};

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