我有以下简单的代码无法正确执行。此项应该使用FMDatabaseQueue（_queue）将对象数组写入sqlite数据库，该NSLog()（_queue）在初始化时被实例化为静态值。这是在单身人士中执行的。注释掉dispatch_async包装会导致正确执行，如dispatch_async语句所示。如您所见，我希望在调用时在后台队列中执行此写操作。对dispatch_async的其他调用在应用程序中正常工作（但不在单例内），所有FMDB操作都不在 -(void)addSafePersonEntryArray:(NSMutableArray *)per
{
NSLog(@"Reaches here with dispatch_async enabled");
dispatch_async(
dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0),^{ //commenting out this
NSLog(@"But not here");
[_queue inTransaction:^(FMDatabase *db, BOOL *rollBack) {
NSLog(@"Nor here");
[db setLogsErrors:YES];
[db setTraceExecution:NO];
[db setKey:self.secretKey];
for(PersonObject *p in per){
[self _addPersonEntryRecord:p db:db];
}
}];
}); // and commenting out this as well as dispatch_async causes all NSLog() statements to be reached and the code works properly.
}
包装器中。
+ (id)sharedManager {
static AppManager *sharedAppManager = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
sharedAppManager = [[self alloc] init];
});
return sharedAppManager;
}
我像这样实例化单身：
.txt我将不胜感激任何建议！