在類中，進行編輯下面的代碼：       NSLog(@"main thread begin...");       [self performSelectorInBackground:@selector(doSomething:) withObject:nil];       NSLog(@"main thread end.....");           - (void) doSomething:(id)sender   {       NSLog( @"one thread begin..." );         NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];       for (int i=0; i<self.StarName_Final.count; i++) {           [self SaveToDataBase:[StarName_Final objectAtIndex:i]];       }       NSLog( @"one thread end..." );         [pool release];   }