iphone - ios 在条件下继续

Question

我正在尝试在某些情况下执行 segue。我在主 Storyboard 中创建了从 nextPushed 按钮到下一个 View Controller 的模态转场。

(IBAction)nextPushed:(id)sender {
//Perform check that every field /date/from/to/ choised and exists  
NSString *fromText = [NSString alloc];
NSString *toText = [NSString alloc];
NSString *pasNumText = [NSString alloc];
NSString *dateText = [NSString alloc];
dateText = self.dateAndTimeLabel.text;
fromText = self.fromLabel.text;
toText = self.toLabel.text;
pasNumText = self.numOfPassengersLabel.text;
if (!([fromText isEqual:@"Choice" ]) && !([toText isEqual:@"Choice"] ) && !([pasNumText isEqual:@"Choice"]) && !([dateText isEqual:@"Choice"])) {
    NSLog(@"All fields choisen");
    NSLog(@"Going to next view");
    [self performSegueWithIdentifier:@"goToDannie" sender:sender];
} else {
    UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Warning" message:@"Not all fields selected" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
    [alert show];
}
}

即使条件不为真，它也会执行 segue，并在下一个 View 中显示警报。

Answer 1

删除从按钮到 View Controller 的转场。相反，从包含 nextButton 的 View Controller 按住 control 并拖动到您要切换到的 View Controller 。然后performSegueWithIdentifier只有满足条件才会运行。