ios - 自定义 UITableViewCell : UITextFields clearing when scrolled out of view- dequeuing problems 的问题

Question

我有一个带有自定义 UITableViewCell 的 UITableView，其中我有向单元格添加文本字段、图像、动画、填充等的方法。

在我的 ViewController 中，我根据需要设置单元格，以满足特定需求，例如第一个和最后一个单元格具有与 UITableView 中的其余单元格不同的图像和占位符文本。

我最初的问题是，当表格使单元格出列并重用它们时，它们的顺序被错误地更改了，但是目前我已经解决了这个问题，但现在发生的是自定义单元格中 UITextFields 中的文本被删除/重新当 tableview 滚动出 View 时排序。理想情况下，我希望用户在文本字段中输入文本，并将其永久保留在该特定单元格中。

根据我的尝试，我想我在将单元格和文本字段代表出队时遇到问题，我哪里出错了？我的文本字段编辑开始/更改/结束方法是在 SearchBarTableViewCell.m 中的正确位置调用的，还是应该在 exploreViewController.m 中？

这是我设置自定义单元格的地方，也是我的 cellForRowAtIndex 方法正在实现的地方:

SEARCHBARTABLEVIEWCELL.m

- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
    self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
    if (self) {
        // Initialization code
    }

    //add search bar
    self.searchBar = [[UITextField alloc]initWithFrame:CGRectMake(0, 5, 280, 40)];
    self.searchBar.backgroundColor = [UIColor whiteColor];
    self.searchBar.keyboardAppearance = UIKeyboardAppearanceDark;
    self.searchBar.delegate = self;
    self.searchBar.font = [UIFont fontWithName:@"AvenirNext-Regular" size:20.0f];
    [self.searchBar setBackgroundColor:[UIColor whiteColor]];
    self.searchBar.layer.cornerRadius = 8;
    self.searchBar.autocapitalizationType = UITextAutocapitalizationTypeNone;
    [self.searchBar setAdjustsFontSizeToFitWidth:NO];
    self.searchBar.textColor = [UIColor colorWithRed:73.0/255.0 green:173.0/255.0 blue:248.0/255.0  alpha:1.0];
    self.searchBar.tintColor =  [UIColor colorWithRed:73.0/255.0 green:173.0/255.0 blue:248.0/255.0  alpha:1.0];
    self.searchBar.layer.borderWidth = 2.0f;
    self.searchBar.layer.borderColor = [[UIColor colorWithRed:73.0/255.0 green:173.0/255.0 blue:248.0/255.0  alpha:1.0] CGColor];
    self.searchBar.layer.cornerRadius = 8.0f;
//    [self.contentView addSubview:self.searchBar];
    [self.searchBar addTarget:self
                       action:@selector(editingChanged:)
             forControlEvents:UIControlEventEditingChanged];
    [self.searchBar addTarget:self
                       action:@selector(editingBegun:)
             forControlEvents:UIControlEventEditingDidBegin];
    [self.searchBar addTarget:self
                       action:@selector(editingEnded:)
             forControlEvents:UIControlEventEditingDidEnd];

    //add the left padding and the left-hand icon to the searchbar textfield
    self.searchBarSpacerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 45, 20)];
    _searchBarIcon = [[UIImageView alloc] initWithFrame:CGRectMake(20, 0,15, 20)];

    _searchBarIcon.contentMode = UIViewContentModeScaleAspectFill;
    [self.searchBarSpacerView addSubview:_searchBarIcon];
    [self.searchBar setLeftViewMode:UITextFieldViewModeAlways];
    _searchBarIcon.tintColor = [UIColor colorWithRed:73.0/255.0 green:173.0/255.0 blue:248.0/255.0  alpha:1.0];
    [_searchBar setLeftView:self.searchBarSpacerView];
    [self.searchBarSpacerView setUserInteractionEnabled:NO];

    //add the far-right padding to the searchbar textfield
    self.searchBarPaddingView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 5, 20)];
    self.searchBar.rightView = self.searchBarPaddingView;
    _searchBar.rightViewMode = UITextFieldViewModeAlways;
    [self.searchBarPaddingView setUserInteractionEnabled:NO];

    //setup the "+" sign for the last cell in the tableview
    self.addRowButton = [[UIButton alloc] initWithFrame:CGRectMake(self.searchBar.frame.size.width - 30,10, 40, 40)];
    self.addRowButtonIcon = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 20, 20)];
    [self.addRowButton addSubview:self.addRowButtonIcon];
    [self.searchBar addSubview:self.addRowButton];

    //setup the "between" and "and" text labels
    self.and = [[UILabel alloc] initWithFrame:CGRectMake(10, 0, 35.5, 40)];
    self.and.font = [UIFont fontWithName:@"AvenirNext-Regular" size:20.0f];
    self.and.textColor = [UIColor colorWithRed:159.0/255.0 green:159.0/255.0 blue:159.0/255.0  alpha:1.0];

    return self;
}

- (IBAction)editingBegun:(UITextField *)sender
{
    NSLog(@"%li + %li", (long)self.rows, (long)self.tag);

    [self delegate];

    if (self.tag == 0) {
        [UIView animateWithDuration:0.2f
                              delay:0.0f
                            options:UIViewAnimationOptionCurveEaseIn
                         animations:^{
                             self.searchBarIcon.transform = CGAffineTransformMakeRotation(DEGREES_TO_RADIANS(-90));
                         }completion:nil];

        if (sender.text.length > 0) {

            [self.and setFrame:CGRectMake(10, 0, 35.5, 40)];
            [self.searchBarSpacerView setFrame:CGRectMake(0, 0, 45, 20)];
            self.and.hidden = YES;

        }

        NSLog(@"FIRSTCELL");
    }
    else if(self.tag <= self.rows-2){

        if (sender.text.length > 0) {

            [self.and setFrame:CGRectMake(10, 0, 35.5, 40)];
            [self.searchBarSpacerView setFrame:CGRectMake(0, 0, 45, 20)];
            self.and.hidden = YES;

        }

        NSLog(@"MIDDLECELL");
    }
    else if(self.tag == self.rows -1 ){
        [UIView animateWithDuration:0.2f
                              delay:0.0f
                            options:UIViewAnimationOptionCurveEaseIn
                         animations:^{
                             self.searchBarIcon.transform = CGAffineTransformMakeRotation(DEGREES_TO_RADIANS(90));
                         }completion:nil];

        if (sender.text.length > 0) {

            [self.and setFrame:CGRectMake(10, 0, 35.5, 40)];
            [self.searchBarSpacerView setFrame:CGRectMake(0, 0, 45, 20)];
            self.and.hidden = YES;

        }

        NSLog(@"LASTCELL");
    }
}

- (IBAction)editingChanged:(UITextField *)sender
{

    [self delegate];

//    NSLog(@"Editing...");
}

- (IBAction)editingEnded:(UITextField *)sender
{

    [self delegate];

    NSLog(@"Editing ended");

    [UIView animateWithDuration:0.2f
                          delay:0.0f
                        options:UIViewAnimationOptionCurveEaseOut
                     animations:^{
                         self.searchBarIcon.transform = CGAffineTransformMakeRotation(DEGREES_TO_RADIANS(0));
                     }completion:nil];

    NSString *rawString = [sender text];
    NSCharacterSet *whitespace = [NSCharacterSet whitespaceAndNewlineCharacterSet];
    NSString *trimmed = [rawString stringByTrimmingCharactersInSet:whitespace];
    if ([trimmed length] != 0) {
        // Text was NOT empty or only whitespace.

            if (sender.text.length > 0) {
                NSLog(@" and in the new textField");

                 if (self.tag == 0){

                    [sender addSubview:self.and];

                     self.and.hidden = NO;
                    [UIView animateWithDuration:0.2f
                                          delay:0.0f
                                        options:UIViewAnimationOptionCurveEaseInOut
                                     animations:^{

                                         [self.between setFrame:CGRectMake(45, 0, 80, 40)];

                                         [self.searchBarSpacerView setFrame:CGRectMake(0, 0, 45+self.between.frame.size.width+4, 20)];

                                     }completion:nil];

                 } else if (self.tag > 0) {

                     [sender addSubview:self.and];
                     self.and.hidden = NO;

                     [UIView animateWithDuration:0.2f
                                           delay:0.0f
                                         options:UIViewAnimationOptionCurveEaseInOut
                                      animations:^{

                                          [self.and setFrame:CGRectMake(45, 0, 35.5, 40)];

                                          [self.searchBarSpacerView setFrame:CGRectMake(0, 0, 45+self.and.frame.size.width+4, 20)];

                                      }completion:nil];
                        self.addRowButton.hidden = NO;

                     //set the padding view to accommodate the "+" button
                     [self.searchBarPaddingView setFrame:CGRectMake(0, 0, 30, 20)];
                     NSLog(@"%f",self.searchBarPaddingView.frame.size.width);
                 }
            }
    } else{
        NSLog(@"There are only blank spaces in this search box!");
        sender.text = @"";
        self.addRowButton.hidden = YES;
        [self.searchBarPaddingView setFrame:CGRectMake(0, 0, 5, 20)];
    }
}

@end

探索 Controller .M

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *cellIdentifier = @"searchCell";

    SearchBarTableViewCell *cell = [self.searchTable dequeueReusableCellWithIdentifier:cellIdentifier];

    if (!cell) {
        cell = [[SearchBarTableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
    }

    if (indexPath.row == 0) {
        cell.searchBarIcon.image = [[UIImage imageNamed:@"firstCell"]imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
        cell.searchBar.placeholder = @"Search between here...";
        cell.and.text = @"Between";


    } else if (indexPath.row == self.cells.count-1) {
        cell.searchBarIcon.image = [[UIImage imageNamed:@"lastCell"]imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
        cell.and.text = @"and";


        cell.searchBar.placeholder = @"...and here";
        [cell.addRowButtonIcon setImage:[UIImage imageNamed:@"addRow"]];
        cell.addRowButton.hidden = YES;
        [cell.addRowButton addTarget:self action:@selector(insertRowsAtIndexPaths:withRowAnimation:) forControlEvents:UIControlEventTouchUpInside];

    } else {
        cell.and.text = @"and";

        cell.searchBarIcon.image = [[UIImage imageNamed:@"anyCell"]imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
        cell.searchBar.placeholder = @"...and here";
        [cell.searchBarIcon setFrame:CGRectMake(20, 2.5,15, 15)];

    }


    // Add utility buttons
    NSMutableArray *rightUtilityButtons = [NSMutableArray new];

    [rightUtilityButtons sw_addUtilityButtonWithColor:[UIColor clearColor] icon:[UIImage imageNamed:@"myLocation"]];
    [rightUtilityButtons sw_addUtilityButtonWithColor:[UIColor clearColor] icon:[UIImage imageNamed:@"deleteCell"]];

    [cell.contentView addSubview:cell.searchBar];

    cell.searchBar.tag = indexPath.row;
    cell.rightUtilityButtons = rightUtilityButtons;
    cell.tag = indexPath.row;
    cell.rows = self.cells.count;
    cell.selectionStyle = UITableViewCellSelectionStyleNone;

    NSLog(@"textfield tag %ld", (long)cell.searchBar.tag);

    return cell;
}

Answer 1

为了避免丢失每个单元格的值，通常的做法是创建一个数组并将每个单元格的值存储到数组中。所以数组将具有全局范围，最好将它声明为您的类的全局变量(EXPLOREVIEWCONTROLLER)。在 ExploreViewController.m 中，就在 @implementation 之前，添加以下内容以完成此操作:

@interface ExploreViewController ()
{
    NSMutableArray *array;
}   

@end

现在，请务必在使用之前在类中的某处初始化数组。通常的做法是将此添加到您类(class)的 init方法。

array = [[NSMutableArray alloc] init];

现在在 (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath您可以使用 [array insertObject: textField.text atIndex: indexPath.row]; 存储每个文本字段的值. cellForRowAtIndexPath: 中遵循的简单逻辑在处理存储值时要遵循的是首先检查数组(表示您的 uitableView 行)是否有任何值，如果有，则使用该数据填充您的字段。其基本代码表示为:

if ([array count] > 0) {
    NSString *textFieldText = [[NSString alloc] init];
    // Will retrieve text from array with the same index as the cell
    textFieldText = [array objectAtIndex: indexPath.row];    
}      

textFieldText 的值现在可以添加到单元格的 textField 中。