NSArray objectAtIndex index 0 beyond bounds for empty array

问题:

I'm working on someone else's app and and I'm getting this error:

'NSRangeException', reason: '*** -[__NSArrayI objectAtIndex:]: index 0   beyond bounds for empty array' 

Xcode points to this line:

 NSDictionary *geo = [response[0] objectForKey:@"geometry"]; 

Here's the full method:

- (void)loadLatLong {  indx ++; if (indx == [datalist count]) {     [self showMarker]; //        self.alertView.hidden = true; //        [self setThreeQuarters];     [self.progressbar setProgress:1.0 animated:YES];     return; } PointClass *pt = datalist[indx]; NSString *stPt = [pt.Location stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]; NSString *str = [stPt stringByReplacingOccurrencesOfString:@" " withString:@"+"]; NSString *url = [NSString stringWithFormat:@"https://maps.google.com/maps/api/geocode/json?address=%@&sensor=false&key=AIzaSyAoSBH8mBmeVp2HVx6vJrkTvl3bjRFiWag",str];  NSURL *urlString = [NSURL URLWithString:url]; AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];  manager.responseSerializer = [AFJSONResponseSerializer serializer]; manager.responseSerializer.acceptableContentTypes = [manager.responseSerializer.acceptableContentTypes setByAddingObject:@"text/html"]; [manager GET:[urlString absoluteString ]parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {     NSArray *response = [responseObject objectForKey:@"results"];     NSDictionary *geo = [response[0] objectForKey:@"geometry"];     NSDictionary *location = [geo objectForKey:@"location"];      pt.lat = [[location objectForKey:@"lat"] doubleValue];     pt.lng = [[location objectForKey:@"lng"] doubleValue];     datalist[indx] = pt;     NSLog([NSString stringWithFormat:@"%%d \n"], indx);     [self loadLatLong];      } failure:^(AFHTTPRequestOperation *operation, NSError *error) {    }]; } 

Can't figure out where to change the code.

UPDATE: I want to add that it only crashes sometimes and sometimes it loads

回答1:

The code makes an assumption that response array always has at least one element. This breaks when the array is empty, so you need to add code to check for it:

NSArray *response = [responseObject objectForKey:@"results"]; if (response.count == 0) {     // Continue loading more data:     [self loadLatLong];     return; } NSDictionary *geo = [response[0] objectForKey:@"geometry"]; 

回答2:

It is crashed because the response don't have any object. You should check it before calling response[0]. Something like this if ([response count] == 0) return;

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