如何检索UISwitch的UITableView行号？ [英] How do I retrieve UITableView row number of a UISwitch?

问题描述

我已经尝试过这里发布的几种方法，但是我无法让我的表充满开关以返回已更改开关的单元格的索引值。我正在以编程方式创建包含表的视图（无xib）。

TableSandboxAppDelegate.m 我在 didFinishLaunchingWithOptions： with：

  ... 
 TableSandboxViewController * sandboxViewController = [[TableSandboxViewController] alloc] 
 init]; 
 [[自我窗口] setRootViewController：sandboxViewController]; 
 ... 
  

TableViewController.h 文件读取：

  @interface TableSandboxViewController：UITableViewController 
 {
 NSMutableArray * _questionOrder; 
 NSMutableArray * switchStates; 
} 
 @end 
  

TableViewController.m cellForRowAtIndexPath：读取：

  UITableViewCell * cell = [tableView dequeueReusableCellWithIdentifier：@ MainCell]; 
 
 UISwitch * theSwitch = nil; 
 
 if（cell == nil）{
 cell = [[UITableViewCell alloc] initWithStyle：UITableViewCellStyleDefault 
 reuseIdentifier：@MainCell]; 
 
 theSwitch = [[UISwitch alloc] initWithFrame：CGRectZero]; 
 theSwitch.tag = 100; 
 [theSwitch addTarget：self action：@selector（switchChanged :) 
 forControlEvents：UIControlEventValueChanged]; 
 [cell.contentView addSubview：theSwitch]; 
 
} else {
 theSwitch = [cell.contentView viewWithTag：100]; 
} 
 
 if（[[switchStates objectAtIndex：indexPath.row] isEqualToString：@ON]）{
 theSwitch.on = YES; 
}其他{
 theSwitch.on = NO; 
} 
 
返回单元格; 
  

TableViewController.m - （IBAction）switchChanged ：（UISwitch *）发件人读取：

  UITableViewCell * theParentCell = [[sender superview] superview] ; 
 NSIndexPath * indexPathOfSwitch = [self.tableView indexPathForCell：theParentCell]; 
 
 NSLog（@Switch在索引处更改：％d，indexPathOfSwitch.row）; 
  

我的日志结果始终是Switch index at index：0。我觉得问题出在CGPoint系列中，我尝试过对发送者（[发送者超级视图]，[[发送者超级视图]超级视图]等的替换组合）。我不觉得那条线指向显示表格的视图。

我做错了什么？

注意添加10 / 9,9：15 EDT： 我的目标是能够处理表中大约100个是/否的问题，因此重用是关键。我想滚动并让表格成为每个开关的状态，并且能够在离开视图时检索它们。

解决方案

标签是一个不错的解决方案，但有点笨拙，因为单元格 - 以及它们的子视图 - 不断被重用，改变它们的行 - 因此它们需要的标签。

<相反，我通常保留其中一个：

   - （NSIndexPath *）indexPathWithSubview：（UIView *）subview {
 
 while（！[subview isKindOfClass：[UITableViewCell self]]&& subview）{
 subview = subview.superview; 
} 
 return [self.tableView indexPathForCell：（UITableViewCell *）subview]; 
} 
  

然后当我得到IBAction时：

   - （IBAction）someSubviewAction：（id）sender {
 
 NSIndexPath * indexPath = [self indexPathWithSubview：（UIView *）sender]; 
 //从这里继续
} 
  

I have tried several approaches posted here, but I cannot get my table full of switches to return an index value for the cell of the changed switch. I am creating the view containing the table programmatically (no xib).

TableSandboxAppDelegate.m I instantiate the view controller in didFinishLaunchingWithOptions: with:

...
TableSandboxViewController *sandboxViewController = [[TableSandboxViewController alloc]
    init];
[[self window] setRootViewController:sandboxViewController];
...

TableViewController.h file reads:

@interface TableSandboxViewController : UITableViewController
{
   NSMutableArray *_questionOrder;
   NSMutableArray *switchStates;
}
@end

TableViewController.m cellForRowAtIndexPath: reads:

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"MainCell"];

UISwitch *theSwitch = nil;

if (cell == nil) {
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
        reuseIdentifier:@"MainCell"];

    theSwitch = [[UISwitch alloc] initWithFrame:CGRectZero];
    theSwitch.tag = 100;
    [theSwitch addTarget:self action:@selector(switchChanged:)   
        forControlEvents:UIControlEventValueChanged];
    [cell.contentView addSubview:theSwitch];

} else {
    theSwitch = [cell.contentView viewWithTag:100];
}

if ([[switchStates objectAtIndex:indexPath.row] isEqualToString:@"ON"]) {
    theSwitch.on = YES;
} else {
    theSwitch.on = NO;
}

return cell;

TableViewController.m -(IBAction)switchChanged:(UISwitch *)sender reads:

UITableViewCell *theParentCell = [[sender superview] superview];
NSIndexPath *indexPathOfSwitch = [self.tableView indexPathForCell:theParentCell];

NSLog(@"Switch changed at index: %d", indexPathOfSwitch.row);

My log result is always "Switch changed at index: 0". I feel like the problem is in that CGPoint line where I've tried combinations of replacements for "sender" ([sender superview], [[sender superview]superview], etc). I don't feel like that line is pointing to the view that displays the table.

What am I doing wrong?

Note added 10/9, 9:15 EDT: my goal is to be able to handle about 100 yes/no questions in the table, so reuse is a key. I want to scroll and have the table the state of each switch, as well as be able to retrieve them when leaving the view.

解决方案

Tags is an okay solution, but a little clumsy because the cells - and therefore their subviews - are continually being reused, changing their rows - and therefore the tags they need.

Instead, I generally keep one of these around:

- (NSIndexPath *)indexPathWithSubview:(UIView *)subview {

    while (![subview isKindOfClass:[UITableViewCell self]] && subview) {
        subview = subview.superview;
    }
    return [self.tableView indexPathForCell:(UITableViewCell *)subview];
}

Then when I get an IBAction:

- (IBAction)someSubviewAction:(id)sender {

    NSIndexPath *indexPath = [self indexPathWithSubview:(UIView *)sender];
    // carry on from here
}

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