2

嗨，我在 tableview 单元格中使用 UIStepper。当 UIStepper 值更改时，我必须在表格视图单元格的标签中显示值。这是代码

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
       UILabel *lblQuantityValue = [[UILabel alloc] initWithFrame:CGRectMake(140, 410, 50, 30)];
       lblQuantityValue.text = @"1";
       lblQuantityValue.tag = indexPath.section;
       lblQuantityValue.backgroundColor = [UIColor clearColor];
       [[lblQuantityValue layer] setCornerRadius:5];
       [[lblQuantityValue layer] setMasksToBounds:YES];
       [[lblQuantityValue layer] setBorderWidth:1.0f];
       [[lblQuantityValue layer] setBorderColor:[[UIColor orangeColor]CGColor]];
       [cell addSubview:lblQuantityValue];

       UIStepper *stepper = [[UIStepper alloc] initWithFrame:CGRectMake(200, 410, 50, 30)];
       [stepper addTarget:self action:@selector(stepper_ValueChanged:) for   ControlEvents:UIControlEventValueChanged];
       stepper.tag = indexPath.row;
       stepper.minimumValue = 1;
       stepper.maximumValue = 10;
       [cell addSubview:stepper];
}

stepper_ValueChanged 方法如下

-(void)stepper_ValueChanged:(UIStepper*)sender
{
 UILabel *lblQuantityValue = (UILabel*)[self.view viewWithTag:sender.tag];
 int value2 = [sender value];
 lblQuantityValue.text = [NSString stringWithFormat:@"%d", value2];
}

我收到如下崩溃报告

-[UIView setText:]: unrecognized selector sent to instance 0x111e10640
2014-02-26 11:22:24.159 Hyderabad Bazar[2115:a0b] *** Terminating app due to uncaught     exception 'NSInvalidArgumentException', reason: '-[UIView setText:]: unrecognized selector sent to instance 0x111e10640'
*** First throw call stack:
(
0   CoreFoundation                      0x0000000101ce3795 __exceptionPreprocess + 165
1   libobjc.A.dylib                     0x00000001019bf991 objc_exception_throw + 43
2   CoreFoundation                      0x0000000101d74bad -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
3   CoreFoundation                      0x0000000101cd509d ___forwarding___ + 973
4   CoreFoundation                      0x0000000101cd4c48 _CF_forwarding_prep_0 + 120
5   Hyderabad Bazar                     0x00000001000202a6 -[CartViewController stepper_ValueChanged:] + 390
6   UIKit                               0x0000000100628a8a -[UIApplication sendAction:to:from:forEvent:] + 104
7   UIKit                               0x0000000100628a20 -[UIApplication sendAction:toTarget:fromSender:forEvent:] + 17
8   UIKit                               0x00000001006fc91c -[UIControl _sendActionsForEvents:withEvent:] + 203
9   UIKit                               0x0000000100a895d7 -[UIStepper _updateCount:] + 338
10  UIKit                               0x0000000100a89346 -[UIStepper endTrackingWithTouch:withEvent:] + 32
11  UIKit                               0x00000001006fbe52 -[UIControl touchesEnded:withEvent:] + 472
12  UIKit                               0x000000010092cc0d _UIGestureRecognizerUpdate + 5149
13  UIKit                               0x000000010065d2e5 -[UIWindow _sendGesturesForEvent:] + 928
14  UIKit                               0x000000010065dfa5 -[UIWindow sendEvent:] + 910
15  UIKit                               0x0000000100637962 -[UIApplication sendEvent:] + 211
16  UIKit                               0x000000010062579f _UIApplicationHandleEventQueue + 9549
17  CoreFoundation                      0x0000000101c72e61 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
18  CoreFoundation                      0x0000000101c72732 __CFRunLoopDoSources0 + 242
19  CoreFoundation                      0x0000000101c8e5bf __CFRunLoopRun + 767
20  CoreFoundation                      0x0000000101c8ded3 CFRunLoopRunSpecific + 467
21  GraphicsServices                    0x000000010408a3a4 GSEventRunModal + 161
22  UIKit                               0x0000000100627a63 UIApplicationMain + 1010
23  Hyderabad Bazar                     0x00000001000274e3 main + 115
24  libdyld.dylib                       0x00000001028067e1 start + 0

请帮我

4

3 回答 3

1

您可能会发现两种不同的方法更可行：

子类 UITableViewCell，添加 UIStepper 和 UILabel 作为单元格的属性，并将单元格添加为 UISteppers valueChanged 操作的目标，当值更改时更新标签。取决于你希望如何坚持事情，这可能会因出队和 prepareForReuse 而变得不稳定，这将我们带到另一个想法......

或者

创建一个适当的类变量或属性 NSMutableArray 来保存所有单元格的文本，无论它们是否可见。标签总是从这个数组中填充，而不是直接从步进器中填充。您仍然使用 Target/Action 对来让单元格响应来自 UIStepper 的 valueChanged 事件，但是您将 tableView 连接为单元格的委托，并使用协议从单元格进行如下调用：

[self.tableViewDelegate newValue:value forCell:self];

然后让 tableView 像这样实现协议方法：

- (void)newValue:(NSString*)value forCell:(CustomCellClassName*)cell
{
    NSIndexPath *indexPath = [self.tableView indexPathForCell:cell];
    //now use the index path to set the "value" parameter at the right place in your class variable or property

    //Now that the data source is updated, refresh the table
    [self.tableView reloadData];
}
于 2014-02-26T07:28:52.900 回答
0

尝试这个，

 -(void)stepper_ValueChanged:(UIStepper*)sender
 {
      int tag = sender.tag;
      int labelTagInCell = //tag of label in cell
      //assumes only 1 section
      NSIndexPath *indexPath = [NSIndexPath indexPathForRow:tag inSection:0];
      UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];
      UILabel *lblQuantityValue = (UILabel*)[cell viewWithTag:labelTagInCell];
      int value2 = [sender value];
      lblQuantityValue.text = [NSString stringWithFormat:@"%d", value2];
 }

最好使用自定义单元格，即：UITableViewCell该类的步进器的子类和控制值更改。

在CustomCell.h

 @property (strong, nonatomic) UILabel *lblQuantityValue;
 @property (strong, nonatomic) UIStepper *stepper;

在CustomCell.m

 - (void)awakeFromNib {
     [super awakeFromNib];
      self.lblQuantityValue = [[UILabel alloc] initWithFrame:CGRectMake(140, 410, 50, 30)];
      self.lblQuantityValue.text = @"1";
      self.lblQuantityValue.tag = indexPath.section;
      self.lblQuantityValue.backgroundColor = [UIColor clearColor];
      [[self.lblQuantityValue layer] setCornerRadius:5];
      [[self.lblQuantityValue layer] setMasksToBounds:YES];
      [[self.lblQuantityValue layer] setBorderWidth:1.0f];
      [[self.lblQuantityValue layer] setBorderColor:[[UIColor orangeColor]CGColor]];
      [self addSubview:lblQuantityValue];

      self.stepper = [[UIStepper alloc] initWithFrame:CGRectMake(200, 410, 50, 30)];
      [self.stepper addTarget:self action:@selector(stepper_ValueChanged:) for   ControlEvents:UIControlEventValueChanged];
      self.stepper.tag = indexPath.row;
      self.stepper.minimumValue = 1;
      self.stepper.maximumValue = 10;
      [self addSubview:stepper];
 }

 -(void)stepper_ValueChanged:(UIStepper*)sender
 {
      int value2 = [self.stepper value];
      self.lblQuantityValue.text = [NSString stringWithFormat:@"%d", value2];
 }
于 2014-02-26T06:55:41.067 回答
0

代码将 indexPath.row 指定为步进标记。在第 0 行（零）中，该标签为零。viewWithTag：返回接收者视图层次结构中的第一个视图，该标签包括接收者。那么问题是

UILabel *lblQuantityValue = (UILabel*)[self.view viewWithTag:sender.tag];

...正在返回 self.view，其标签无疑是零。快速的解决方案是将标签设置为 row+1，并相应地调整查找。

于 2014-02-26T06:18:33.363 回答