在功能完成之前我无法隐藏视图

Question

我想在最近的Station功能开始之前隐藏多个SearchView但是没有成功，它会在最近的站点完成后隐藏

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath   
*)indexPath
{
    if (tableView == self.localityTableView){
        [self.multipleSearchView setHidden:TRUE];
        [self closestStation:locality.latitude :locality.longitude];
     }

}


- (void) closestStation  :(float) latitude :(float) longitude{
    // this function takes 3 or 4 second
}

Answer 1

那是因为你在主队列中有一个繁重的操作。将您的-closestStation:放入后台队列以解决此问题。

Answer 2

UI更新也需要一段时间（在下一个周期中）。试试这个：

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath*)indexPath
{
if (tableView == self.localityTableView){
    [self.multipleSearchView setHidden:TRUE];

    dispatch_async(dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        [self closestStation:locality.latitude :locality.longitude];
    });
    }
}


- (void) closestStation  :(float) latitude :(float) longitude{

// SQLite query here to find the closest places 

if (self.places.count == 0){

    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"No Results"
                                                    message:@"No results match your  
                                                    search. try with other criteria"
                                                   delegate:nil
                                          cancelButtonTitle:@"OK"
                                          otherButtonTitles:nil];
    [alert show];

}
else {
    [self displayAnnotations];
}

}


-(void) displayAnnotations{
    NSMutableArray *annotations = [[NSMutableArray alloc] init];

    for (Station *item in self.places)
    {
        PlaceAnnotation *annotation = [[PlaceAnnotation alloc] init];
        annotation.coordinate = item.coordinate;
        annotation.title = item.stationName;
        annotation.subtitle = item.address1;
        annotation.station = item;
        [annotations addObject:annotation];      
    }

if (annotations.count > 0){
    [self.mapView addAnnotations:annotations];
}

}

Answer 3

尝试使用performSelectorInBackground。