遗憾的是，我知道问题出在哪里，但我是新手，不知道处理它的最佳方法。我已阅读苹果文档和此处的所有相关问题，但无法充分找到或解释这些信息。
正如您将在下面看到的。我有一个包含 19 个单元格的 tableview。第 0 节中的 2，第 1 节中的 17。一切正常，除了滚动时，我知道这是因为 tableview 正在重用单元格，所以当我尝试保存时，如我下面的代码所示，这些单元格根本不存在因此，当我尝试保存时，我认为不存在的任何内容都是 nil 字符串参数，因此我的实体最终为 NaN。
从我的所有单元格中维护和保存文本字段信息的适当方法是什么？在此先感谢您的帮助!
- (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);
}
最佳答案
请记住，UITextField 是 View ，不应存储数据，而应只是显示/检索数据。您的模型 (self.metrics) 应该是您存储信息的地方，并且应该在您从用户那里收到信息后立即存储它，这样文本字段消失或消失都没有关系得到重用。
为了做到这一点，您可以使用以下方法，每当有人停止编辑文本字段时调用该方法(确保您将所有文本字段的委托(delegate)设置为您的 Controller ):
-(void) textFieldDidEndEditing:(UITextField *)textField
{
// Figure out which textField this is and save the data to the appropriate place in your model
}
现在，有点棘手的部分是确定您在此方法中使用的是哪个文本字段。
您可以在 cellForRowAtIndexPath 中设置标签，然后在此处查找标签号以确定它是哪个，或者您可以通过索引路径来完成，因为无论如何您已经在这样做了:
CGRect position = [self convertRect:textField.frame toView:self.tableView];
NSArray *indexPaths = [self.tableView indexPathsForRowsInRect:position];
NSIndexPath *indexPath = [indexPaths objectAtIndex:0];
关于ios - 滚动单元格双端队列时如何维护和保存自定义单元格文本字段输入数据，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/16885980/