UITableView滚动后UITextFields重叠

Posted 2023-03-04

【中文标题】UITableView滚动后UITextFields重叠

【英文标题】：UITextFields Overlapping After UITableView Scroll

【发布时间】：2012-04-11 19:06:44

【问题描述】：

我有一个带有 UITextFields 的 UITableView 来制作表单。它看起来很棒——除非你滚动新的 UITextFields 被放在旧的 UITextFields 之上......我不知道为什么！我知道当单元格被重用时（即 dequeueReusableCellWithIdentifier 返回非零），单元格与现有的 UITextField 一起返回。我找到了一个解决方案来保持标签的唯一性，最好删除任何以前的 UITextField。但我不想那样做。在提交此表单的最后，我想从文本字段中获取所有值（如果我删除它们就不能这样做）..

这里是代码。任何帮助表示赞赏！

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

static NSString *CellIdentifier = @"Cell";

UITableViewCell *cell = (UITableViewCell *) [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

if (cell == nil)
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];

cell.accessoryType = UITableViewCellAccessoryNone;

UITextField *playerTextField = [[UITextField alloc] initWithFrame:CGRectMake(155, 15, 130, 30)];
playerTextField.adjustsFontSizeToFitWidth = YES;
playerTextField.textColor = [UIColor blackColor];

if (indexPath.row == 0) 
    playerTextField.placeholder = @"Unique ID Sample";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyNext;


else if (indexPath.row == 1) 
    playerTextField.placeholder = @"Common Name";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;


else if (indexPath.row == 2) 
    playerTextField.placeholder = @"Scientific Name";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;


else if ([indexPath row] == 3) 
    playerTextField.placeholder = @"03/25/1992";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;


else if ([indexPath row] == 4) 
    playerTextField.placeholder = @"Male";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;
 

else if ([indexPath row] == 5) 
    playerTextField.placeholder = @"03/01/2012";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;


else if ([indexPath row] == 6) 
    playerTextField.placeholder = @"Huntington, WV";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;


else if ([indexPath row] == 7) 
    playerTextField.placeholder = @"Huntington, WV";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;


else if ([indexPath row] == 8) 
    playerTextField.placeholder = @"Marshall University";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;
 
else if ([indexPath row] == 9) 
    playerTextField.placeholder = @"Sub Straight";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;


else if ([indexPath row] == 10) 
    playerTextField.placeholder = @"Any Light";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;


else if ([indexPath row] == 11) 
    playerTextField.placeholder = @"Temperature";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;


else if ([indexPath row] == 12) 
    playerTextField.placeholder = @"A Lot";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;
 

else if ([indexPath row] == 13) 
    playerTextField.placeholder = @"All Types";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;


else if ([indexPath row] == 14) 
    playerTextField.placeholder = @"Schedule";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;


else if ([indexPath row] == 15) 
    playerTextField.placeholder = @"MM/DD/YYYY";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;


else if ([indexPath row] == 16) 
    playerTextField.placeholder = @"Ate Someone";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;
 

else if ([indexPath row] == 17) 
    playerTextField.placeholder = @"MM/DD/YYYY";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;


else if ([indexPath row] == 18) 
    playerTextField.placeholder = @"The Morgue";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;


else if ([indexPath row] == 19) 
    playerTextField.placeholder = @"MM/DD/YYYY";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;


else if ([indexPath row] == 20) 
    playerTextField.placeholder = @"MM/DD/YYYY";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;
 

else if ([indexPath row] == 21) 
    playerTextField.placeholder = @"To/ From";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyDone;
    

playerTextField.backgroundColor = [UIColor whiteColor];
playerTextField.autocorrectionType = UITextAutocorrectionTypeNo; // no auto correction support
playerTextField.autocapitalizationType = UITextAutocapitalizationTypeNone; // no auto capitalization support
playerTextField.textAlignment = UITextAlignmentLeft;
playerTextField.tag = 0;

playerTextField.clearButtonMode = UITextFieldViewModeNever; // no clear 'x' button to the right
[playerTextField setEnabled: YES];

    [cell addSubview:playerTextField];

[playerTextField release];

cell.textLabel.text = [self.options objectAtIndex:indexPath.row];


return cell;    

【问题讨论】：

为什么多次添加相同的属性？

【参考方案1】：

您将不得不创建一个自定义UITableViewCell。这将允许您使用可以直接访问的UITextField 创建一个ivar。这样，当单元格出列并重用时，您只需在需要时进行设置。请务必在您的单元子类中覆盖 prepareForReuse: 并重置您添加的组件的所有属性。

另一件可以帮助您解决上述代码的事情是使用typedef enum 而不是使用整数来确定它是什么类型的单元格：

typedef enum
    PlayerFieldId = 0,
    PlayerFieldName,
    PlayerFieldGender
 PlayerFields

然后在您的自定义单元格中，您可以通过上面的枚举和 switch 语句设置单元格的类型：

switch(type)
case PlayerFieldId:
    playerTextField.placeholder = @"Unique ID Sample";
    playerTextField.keyboardType = UIKeyboardTypeDefault;
    playerTextField.returnKeyType = UIReturnKeyNext;
    break;
    /* other fields here */

【参考方案2】：

你可以继承 UITableViewCell 并让它有一个你为每个单元格设置的 UITextField 属性，而不是不断添加一个新的，如果你不想删除它们。

【参考方案3】：

使用以下语句创建单元格实例。

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];

for (UITextView *txtView in cell.contentView.subviews)

    if ([txtView isKindOfClass:[UITextView class]])
    
        [txtView removeFromSuperview];
    


if (cell == nil) 
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:simpleTableIdentifier];