当滚动单元格时，如何维护和保存自定义单元格文本框输入数据deque

问题描述：

不幸的是，我知道问题是什么，但我是绿色的，不知道处理它的最佳方式。我已经阅读了苹果文档和所有相关问题，无法充分发现或解释信息。当滚动单元格时，如何维护和保存自定义单元格文本框输入数据deque

正如您将在下面看到的。我有19个单元格的tableview。 2在第0节，17在第1节。一切工作正常，除了当我滚动时，我知道这是因为tableview重用单元格，所以当我试图保存下面我的代码中看到这些单元格根本不存在因此，当我尝试保存时，任何不在我看来的东西都是零字符串参数，因此我的实体最终以NaN结尾。

什么是适当的方法来维护和保存我的所有细胞的文本框信息？预先感谢任何帮助！

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

{

UITableViewCell *newCell; 

if (indexPath.section == 0 && indexPath.row == 0) { 
    NSString *cellIdentifier = @"RNDateCell"; 
    RNCommentCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier]; 
    if (cell == nil) { 
     NSArray *nib = [[NSBundle mainBundle]loadNibNamed:@"RNCommentCell" owner:self options:nil]; 
     cell = [nib objectAtIndex:0]; 
     cell.commentLabel.text = NSLocalizedString(@"Date:", @"Date:"); 
     cell.commentField.text = [NSString stringWithFormat:@"%@", self.metrics.timeStamp.description]; 
     newCell = cell; 
    } 
} 

if (indexPath.section == 0 && indexPath.row == 1) { 
    NSString *cellIdentifier = @"RNCommentCell"; 
    RNCommentCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier]; 
    if (cell == nil) { 
     NSArray *nib = [[NSBundle mainBundle]loadNibNamed:@"RNCommentCell" owner:self options:nil]; 
     cell = [nib objectAtIndex:0]; 
     cell.commentLabel.text = NSLocalizedString(@"Comment:", @"Comment:"); 
     cell.commentField.text = self.metrics.comment; 
     newCell = cell; 
    } 
} 

if (indexPath.section == 1) { 
    static NSString *numericCellIdentifier = @"RNNumericCell"; 
    RNNumericCell *cell = (RNNumericCell *)[tableView dequeueReusableCellWithIdentifier:numericCellIdentifier]; 
    if (cell == nil) { 
     NSArray *nib = [[NSBundle mainBundle]loadNibNamed:@"RNNumericCell" owner:self options:nil]; 
     cell = [nib objectAtIndex:0]; 

     switch (indexPath.row) { 
      case 0: 
       cell.numericCellLabel.text = NSLocalizedString(@"Weight:", @"Weight:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.weight]; 
       newCell = cell; 
       break; 
      case 1: 
       cell.numericCellLabel.text = NSLocalizedString(@"Height:", @"Height:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.height]; 
       newCell = cell; 
       break; 
      case 2: 
       cell.numericCellLabel.text = NSLocalizedString(@"Neck:", @"Neck:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.neck]; 
       newCell = cell; 
       break; 
      case 3: 
       cell.numericCellLabel.text = NSLocalizedString(@"Chest:", @"Chest:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.chest]; 
       newCell = cell; 
       break; 
      case 4: 
       cell.numericCellLabel.text = NSLocalizedString(@"Waist:", @"Waist:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.waist]; 
       newCell = cell; 
       break; 
      case 5: 
       cell.numericCellLabel.text = NSLocalizedString(@"Hips:", @"Hips:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.hips]; 
       newCell = cell; 
       break; 
      case 6: 
       cell.numericCellLabel.text = NSLocalizedString(@"Biceps:", @"Biceps:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.biceps]; 
       newCell = cell; 
       break; 
      case 7: 
       cell.numericCellLabel.text = NSLocalizedString(@"Forearms:", @"Forearms:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.forearms]; 
       newCell = cell; 
       break; 
      case 8: 
       cell.numericCellLabel.text = NSLocalizedString(@"Wrists:", @"Wrists:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.wrists]; 
       newCell = cell; 
       break; 
      case 9: 
       cell.numericCellLabel.text = NSLocalizedString(@"Quads Thighs:", @"Quads Thighs:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.quadsThighs]; 
       newCell = cell; 
       break; 
      case 10: 
       cell.numericCellLabel.text = NSLocalizedString(@"Calves:", @"Calves:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.calves]; 
       newCell = cell; 
       break; 
      case 11: 
       cell.numericCellLabel.text = NSLocalizedString(@"Ankles:", @"Ankles:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.ankles]; 
       newCell = cell; 
       break; 
      case 12: 
       cell.numericCellLabel.text = NSLocalizedString(@"Feet:", @"Feet:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.feet]; 
       newCell = cell; 
       break; 
      case 13: 
       cell.numericCellLabel.text = NSLocalizedString(@"BMI:", @"BMI:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.bmi]; 
       newCell = cell; 
       break; 
      case 14: 
       cell.numericCellLabel.text = NSLocalizedString(@"BMR:", @"BMR:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.bmr]; 
       newCell = cell; 
       break; 
      case 15: 
       cell.numericCellLabel.text = NSLocalizedString(@"Waist/Height R:", @"Waist/Height R:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.waistToHeightRatio]; 
       newCell = cell; 
       break; 
      case 16: 
       cell.numericCellLabel.text = NSLocalizedString(@"Waist/Hips R:", @"Waist/Hips R:"); 
       cell.numericField.text = [NSString stringWithFormat:@"%@", self.metrics.waistToHipRatio]; 
       newCell = cell; 
       break; 
      default: 
       break; 
     } 
    } 
} 
return newCell;

}

- (void)saveData

{

NSDateFormatter *dateFormat; 
RNCommentCell *dateCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0]]; 
self.metrics.timeStamp = [dateFormat dateFromString:dateCell.commentField.text]; 

RNCommentCell *commentCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:1 inSection:0]]; 
self.metrics.comment = commentCell.commentField.text; 


RNNumericCell *weightCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:1]]; 
self.metrics.weight = [NSDecimalNumber decimalNumberWithString:weightCell.numericField.text]; 

RNNumericCell *heightCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:1 inSection:1]]; 
self.metrics.height = [NSDecimalNumber decimalNumberWithString:heightCell.numericField.text]; 

RNNumericCell *neckCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:2 inSection:1]]; 
self.metrics.neck = [NSDecimalNumber decimalNumberWithString:neckCell.numericField.text]; 

RNNumericCell *chestCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:3 inSection:1]]; 
self.metrics.chest = [NSDecimalNumber decimalNumberWithString:chestCell.numericField.text]; 

RNNumericCell *waistCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:4 inSection:1]]; 
self.metrics.waist = [NSDecimalNumber decimalNumberWithString:waistCell.numericField.text]; 

RNNumericCell *hipsCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:5 inSection:1]]; 
self.metrics.hips = [NSDecimalNumber decimalNumberWithString:hipsCell.numericField.text]; 

RNNumericCell *bicepsCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:6 inSection:1]]; 
self.metrics.biceps = [NSDecimalNumber decimalNumberWithString:bicepsCell.numericField.text]; 

RNNumericCell *forearmCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:7 inSection:1]]; 
self.metrics.forearms = [NSDecimalNumber decimalNumberWithString:forearmCell.numericField.text]; 

RNNumericCell *wristsCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:8 inSection:1]]; 
self.metrics.wrists = [NSDecimalNumber decimalNumberWithString:wristsCell.numericField.text]; 

RNNumericCell *quadsCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:9 inSection:1]]; 
self.metrics.quadsThighs = [NSDecimalNumber decimalNumberWithString:quadsCell.numericField.text]; 

RNNumericCell *calvesCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:10 inSection:1]]; 
self.metrics.calves = [NSDecimalNumber decimalNumberWithString:calvesCell.numericField.text]; 

RNNumericCell *anklesCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:11 inSection:1]]; 
self.metrics.ankles = [NSDecimalNumber decimalNumberWithString:anklesCell.numericField.text]; 

RNNumericCell *feetCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:12 inSection:1]]; 
self.metrics.feet = [NSDecimalNumber decimalNumberWithString:feetCell.numericField.text]; 

RNNumericCell *bmiCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:13 inSection:1]]; 
self.metrics.bmi = [NSDecimalNumber decimalNumberWithString:bmiCell.numericField.text]; 

RNNumericCell *bmrCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:14 inSection:1]]; 
self.metrics.bmr = [NSDecimalNumber decimalNumberWithString:bmrCell.numericField.text]; 

RNNumericCell *waistToHeightCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:15 inSection:1]]; 
self.metrics.waistToHeightRatio = [NSDecimalNumber decimalNumberWithString:waistToHeightCell.numericField.text]; 

RNNumericCell *waistToHipCell = (id)[self.tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:16 inSection:1]]; 
self.metrics.waistToHipRatio = [NSDecimalNumber decimalNumberWithString:waistToHipCell.numericField.text]; 

NSError *error; 
if (![self.managedObjectContext save:&error]) { 
    NSLog(@"Error saving context: %@", error); 
}

}

答

请记住，UITextField是视图，不应该存储数据，而只是显示/检索它。您的型号（self.metrics）应该是您存储信息的地方，并且应该在您从用户处收到信息后立即存储，以便文本字段消失或重新使用时无关紧要。

为了做到这一点，您可以使用下面的方法，每当有人站编辑的文本字段被称为（请确保您所有的文本字段的委托设置为您的控制器）：

-(void) textFieldDidEndEditing:(UITextField *)textField 
{ 
    // Figure out which textField this is and save the data to the appropriate place in your model 
}

现在，稍微棘手的部分是找出你在这个方法中使用哪个文本字段。

您可以设置的cellForRowAtIndexPath标签，然后在这里查找标签号，以确定其是，或者您也可以通过索引路径做到这一点，因为这是你在做什么已经反正：

CGRect position = [self convertRect:textField.frame toView:self.tableView]; 
NSArray *indexPaths = [self.tableView indexPathsForRowsInRect:position]; 
NSIndexPath *indexPath = [indexPaths objectAtIndex:0];

非常感谢你让我看到了实现它的正确方法。我不够聪明，不知道如何使用您提供的索引代码。然而，只需将cell.texfield.tag = XXXX添加到我的单元格中的每一行索引路径中，然后引用texfielddidendediting中的单元格以将数据保存到我的模型中，这对我来说很容易遵循并且工作得很好，希望这是一个经过批准和有效的方法。欢呼并再次感谢！ – Narsil

不客气！您可以像在cellForRowAtIndexPath中一样使用indexPath。无论哪种方式，尽管它是一个完全有效的方式！由于您是该网站的新手，请确保投票通过点击旁边的向上箭头帮助您的所有答案（无论您是否提问）。:) – lnafziger

非常感谢，现在我有信誉，我会这样做！ – Narsil

答

更新您self.metrics.'whatever'数据发生更改时只会将度量标准保存在您的save中，而不是试图从单元格中获取。换句话说，不要将单元用作数据存储位置。

谢谢你这有助于为我提供更好的视角。现在只是为了实现它。 – Narsil

当滚动单元格时，如何维护和保存自定义单元格文本框输入数据deque

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