ios - 将信息传递给 UIAlertView 委托(delegate)

Question

在用户确认后，我正在尝试使用警报 View 删除 TableView 中的一行。但是我不知道如何让 UIAlertViewDelegate方法知道要删除表中的哪一行。

// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        UIAlertView *alert_delete = [[UIAlertView alloc]initWithTitle:[NSString stringWithFormat:@"Confirm Delete %@",[names objectAtIndex:indexPath.row] ] message:@"Warning all student data will be earsed" delegate:self cancelButtonTitle:@"Dismess" otherButtonTitles:@"YES", nil];
        [alert_delete show];

        // Delete the row from the data source
        [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
    } else if (editingStyle == UITableViewCellEditingStyleInsert) {
        // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
    }   
}

在警报方法中，我尝试处理它以从表和数据库中删除行

    -(void) alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{
        NSString*title = [alertView buttonTitleAtIndex:buttonIndex];
        if ([title isEqualToString:@"YES"]) {
           // how to pass indexPath.row to alertview 
             [names removeObjectAtIndex:indexPath.row];
        }


    }

Answer 1

如果你想向委托(delegate)传递一些东西，那么在调用警报 View 之前向委托(delegate)类添加一个属性并将信息传递给它:

@interface AlertDelegate : NSObject <UIAlertViewDelegate>
@property (nonatomic) NSIndexPath *indexPath;
@end

// @implementation AlertDelegate omitted

并这样使用:

UIAlertView *alertView = ...;
AlertDelegate *delegate = [AlertDelegate new];
alertView.delegate = delegate;
delegate.indexPath = indexPathFromSomewhere;
[alertView show];   // or whatever

如果代表是 self ，那么这意味着将属性添加到 self (或使用私有(private)实例变量)。

在委托(delegate)方法中，您可以访问 indexPath:

-(void) alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{
    NSString*title = [alertView buttonTitleAtIndex:buttonIndex];
    if ([title isEqualToString:@"YES"]) {
        [names removeObjectAtIndex:self.indexPath.row];
    }
}