Question

我有一个带有三个过渡的segue（参见下面的代码）。第一个来自一个按钮。这非常有效。第二种是通过在表格视图中点击单元格。那个也很完美。第三个是tableview单元格中的附件按钮。这个打开了正确的视图控制器，但没有像我编码那样传递对患者的引用。我已经通过新视图控制器的viewDidLoad中的NSLog语句验证了这一点，并将患者显示为null。

-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {

    if ([[segue identifier] isEqualToString:@"addPatient"]) {

        // to add a new patient (selection segue)

        UINavigationController *navigationController = segue.destinationViewController;

        RXAddPatientViewController *addPatientViewController = (RXAddPatientViewController*)navigationController.topViewController;

        Patient *addPatient = [NSEntityDescription insertNewObjectForEntityForName:@"Patient" inManagedObjectContext:[self managedObjectContext]];

        addPatientViewController.addPatient = addPatient;
    }

    if ([[segue identifier] isEqualToString:@"toPrescriptions"]) {

        // to view prescriptions for the selected patient (selection segue)

        RXPrescriptionsViewController *prescriptionViewController = [segue destinationViewController];

        NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];

        Patient *selectedPatient = (Patient*) [self.fetchedResultsController objectAtIndexPath:indexPath];

        prescriptionViewController.selectedPatient = selectedPatient;

        NSLog(@"Selected Patient is %@", selectedPatient.patientFirstName);

    }

    if ([[segue identifier] isEqualToString:@"editPatient"]) {

        // to edit the selected patient (accessory action)

        UINavigationController *navigationController = segue.destinationViewController;

        RXEditPatientViewController *editPatientViewController = (RXEditPatientViewController*)navigationController.topViewController;

        NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];

        Patient *editPatient = (Patient*) [self.fetchedResultsController objectAtIndexPath:indexPath];

        // passing a reference to the editPatientViewController
        editPatientViewController.editPatient = editPatient;

        NSLog(@"Selected patient is %@", editPatient.patientFirstName);
    }
}

Answer 1

当您单击附件按钮时，indexPathForSelectedRow将为null，因为您没有选择该行。但是，prepareForSegue：sender：中的sender参数将是包含附件按钮的单元格。因此，您应该使用以下方法来获取indexPath（请注意我已将参数的类型从id更改为UITableViewCell）：

-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(UITableViewCell *)sender {

     if ([[segue identifier] isEqualToString:@"editPatient"]) {

        // to edit the selected patient (accessory action)

        UINavigationController *navigationController = segue.destinationViewController;

        RXEditPatientViewController *editPatientViewController = (RXEditPatientViewController*)navigationController.topViewController;

        NSIndexPath *indexPath = [self.tableView indexPathForCell:sender];

        Patient *editPatient = (Patient*) [self.fetchedResultsController objectAtIndexPath:indexPath];

        // passing a reference to the editPatientViewController
        editPatientViewController.editPatient = editPatient;

        NSLog(@"Selected patient is %@", editPatient.patientFirstName);
}

无法使用附件指示器进行切换

1 个答案: