ios - What's the best way to ensure a UITableView reloads atomically? -

i'v got uitableview datasource updated @ random intervals in short period of time. more objects discovered, added tableview's data source , insert specific indexpath:

[self.tableview beginupdates]; [self.tableview insertrowsatindexpaths:@[indexpath] withrowanimation:uitableviewrowanimationautomatic]; [self.tableview endupdates]; 

the data source located in manager class, , notification posted when changes.

- (void)addobjecttodatasource:(nsobject*)object {     [self.datasource addobject:object];     [[nsnotificationcenter defaultcenter] postnotification:@"datasourceupdate" object:nil]; } 

the viewcontroller updates tableview when receives notification.

- (void)handledatasourceupdate:(nsnotification*)notification {     nsobject *object = notification.userinfo[@"object"];     nsindexpath *indexpath = [self indexpathforobject:object];      [self.tableview beginupdates];     [self.tableview insertrowsatindexpaths:@[indexpath] withrowanimation:uitableviewrowanimationautomatic];     [self.tableview endupdates]; } 

this works fine, noticed in cases, second object discovered first 1 calling endupdates, , exception claiming have 2 objects in data source when tableview expecting one.

i wondering if has figured out better way atomically insert rows tableview. thinking of putting @synchronized(self.tableview) block around update, i'd avoid if possible because expensive.

the method i've recommended create private queue synchronously posting batch updates onto main queue (where addrow method inserts item data model @ given indexpath):

@interface mymodelclass () @property (strong, nonatomic) dispatch_queue_t mydispatchqueue; @end  @implementation mymodelclass  - (dispatch_queue_t)mydispatchqueue {     if (_mydispatchqueue == nil) {         _mydispatchqueue = dispatch_queue_create("mydispatchqueue", null);     }     return _mydispatchqueue; }  - (void)addrow:(nsstring *)data atindexpath:(nsindexpath *)indexpath {     dispatch_async(self.mydispatchqueue, ^{         dispatch_sync(dispatch_get_main_queue(), ^{             //update data model here             [self.tableview beginupdates];             [self.tableview insertrowsatindexpaths:@[indexpath] withrowanimation:uitableviewrowanimationautomatic];             [self.tableview endupdates];         });     }); } 

by doing way, don't block other threads , block-based approach ensures table view's animation blocks (the ones throwing exceptions) executed in right order. there more detailed explanation in rapid row insertion uitableview causes nsinternalinconsistencyexception.