iphone - 滚动之前加载 UITableView 中的所有单元格

Question

我有一个 UITableView，总共有 8 个单元格(部分)，其中 6 个包含文本字段作为 subview ，其中 2 个包含按钮，另一个包含 TextView 。现在我在这里遇到了问题，因为我们都是意识到，当 View 仅出现时，可见单元格就会加载。因此，当我的应用程序加载时，我可以查看 5 个单元格，前 4 个包含文本字段，第 5 个单元格包含按钮。我可以看到数组计数为 4当我通过登录控制台显示它时，即

there are 4 objects in the array

现在滚动表格 View 后，我可以观察到以下内容:

there are 6 objects in the array

所以，发生的情况是，如果我要保存在 TableView 中输入的数据，或者说编辑以更改现有数据，我将被迫滚动 TableView 并在最后一个单元格中输入值。这样用户的情况不可能总是如此，因为我们不能期望他/她滚动表格 View 并输入完整的表单/表格 View 单元格条目。他/她所做的任何更改都会发生，只需单击完成/保存即可这是..!

此外，我有一个选择器 View 作为包含文本字段作为 subview 的最后一个单元格的输入 View 。因此，在我的选择器 View 中确实选择了行方法，我面临着包含选择器的最后一个单元格/部分(textField 作为 subview )的崩溃问题查看这里是我的方法的代码片段:

-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{

    switch (tagValues) 
    {

        case 105:
        {
            self.textField = [self.fields objectAtIndex:3];
            self.textField.text = [self.reminder objectAtIndex:row];
        }
            break;

        case 107:
        {
            //Crash occurring in this case,sometimes its working wonder why
            self.textField = [self.fields objectAtIndex:5];
            self.textField.text = [self.group objectAtIndex:row];
        }
            break;

    }

}

**Note**:I am using the same textField for adding as subview to all 6 cells,but each one with unique tags and own purpose,i.e. one for editing text using key board,one with date picker,one with general picker etc...

我想知道为什么有时从选择器 View (最后一节单元格)选择值后有时会崩溃，有时工作正常。有时它会在 case 107 中注释的上述行处崩溃，有时会崩溃在主自动释放池中。某些时间线程如下所示:

有什么方法可以让我们一次加载所有单元格，以便在滚动之前将所有文本字段添加到数组中。我相信不会有任何问题

更详细的编辑代码以供理解:

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

     //NSString *identifier = @"UITableViewCell";

    NSString *cellIdentifierF = nil;

    static NSString *firstCellIdentifier = @"FirstCell";
    static NSString *secondCellIdentifier = @"SecondCell";
    static NSString *thirdCellIdentifier = @"ThirdCell";
    static NSString *fourthCellIdentifier = @"FourthCell";
    static NSString *fifthCellIdentifier = @"FifthCell";
    static NSString *sixthCellIdentifier = @"SixthCell";
    static NSString *seventhCellIdentifier = @"SeventhCell";
    static NSString *eightCellIdentifier = @"EightCell";

    if(indexPath.section == 0 && indexPath.row == 0) 
    {
        cellIdentifierF = firstCellIdentifier;
    } 
    else if(indexPath.section == 1 && indexPath.row == 0)
    {
        cellIdentifierF = secondCellIdentifier;
    }
    else if(indexPath.section == 2 && indexPath.row == 0)
    {
        cellIdentifierF = thirdCellIdentifier;
    }
    else if(indexPath.section == 3 && indexPath.row == 0)
    {
        cellIdentifierF = fourthCellIdentifier;
    }
    else if(indexPath.section == 4 && indexPath.row == 0)
    {
        cellIdentifierF = fifthCellIdentifier;
    }
    else if(indexPath.section == 5 && indexPath.row == 0)
    {
        cellIdentifierF = sixthCellIdentifier;
    }
    else if(indexPath.section == 6 && indexPath.row == 0)
    {
        cellIdentifierF = seventhCellIdentifier;
    }
    else if(indexPath.section == 7 && indexPath.row == 0)
    {
        cellIdentifierF = eightCellIdentifier;
    }

    UITableViewCell *cell = (UITableViewCell *)[atableView dequeueReusableCellWithIdentifier:cellIdentifierF];

        atableView.backgroundColor = [UIColor clearColor];

        textField = [[[UITextField alloc]initWithFrame:CGRectMake(15, 12, 300, 24)]autorelease];
        textField.textColor = [UIColor whiteColor];
        textField.delegate = self;
        tagValues = textField.tag;

    switch (indexPath.section) 
    {
        case 0:
        {
            if (cell == nil) 
            {
                cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:cellIdentifierF] autorelease];
                cell.backgroundColor = [[UIColor alloc]initWithPatternImage:[UIImage imageNamed:@"buttonbg-1.png"]];

                //Only add content to cell if it is new
                if([cellIdentifierF isEqualToString: firstCellIdentifier])
                {
                    textField.placeholder = @"Enter name";
                    [self.textField setValue:[UIColor purpleColor] 
                                  forKeyPath:@"_placeholderLabel.textColor"];
                    textField.tag = 101;
                    textField.text = reminderInstance.Name;
                    textField.autocorrectionType = UITextAutocorrectionTypeNo;
                    NSLog(@"Value = %@",textField.text);
                    [cell.contentView addSubview:textField];
                    [self.fields addObject:textField];
                }
            }
        }
            break;

        case 1:
        {
            if (cell == nil) 
            {
                cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:cellIdentifierF] autorelease];
                cell.backgroundColor = [[UIColor alloc]initWithPatternImage:[UIImage imageNamed:@"buttonbg-1.png"]];

                //Only add content to cell if it is new
                if([cellIdentifierF isEqualToString: secondCellIdentifier])
                {
                    textField.tag = 102;
                    textField.text = reminderInstance.Event;
                    NSLog(@"Value = %@",textField.text);
                    [cell.contentView addSubview:textField];
                    [self.fields addObject:textField];
                }
            }
        }
            break;

        case 2:
        {
            if (cell == nil) 
            {
                cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:cellIdentifierF] autorelease];
                cell.backgroundColor = [[UIColor alloc]initWithPatternImage:[UIImage imageNamed:@"buttonbg-1.png"]];

                //Only add content to cell if it is new
                if([cellIdentifierF isEqualToString: thirdCellIdentifier])
                {
                    textField.placeholder = @"Click here to set date and time";
                    [self.textField setValue:[UIColor purpleColor] 
                                  forKeyPath:@"_placeholderLabel.textColor"];
                    textField.inputView = self.datePicker;
                    textField.text = reminderInstance.Date;
                    textField.tag = 103;
                    NSLog(@"Value = %@",textField.text);
                    [cell.contentView addSubview:textField];
                    [self.fields addObject:textField];
                }
            }
        }   
            break;

        case 3:
        {
            if (cell == nil) 
            {
                cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:cellIdentifierF] autorelease];
                cell.backgroundColor = [[UIColor alloc]initWithPatternImage:[UIImage imageNamed:@"buttonbg-1.png"]];

                //Only add content to cell if it is new
                if([cellIdentifierF isEqualToString: fourthCellIdentifier])
                {
                    textField.tag = 105;
                    textField.text = reminderInstance.numDays;
                    textField.inputView = self.reminderPicker;
                    NSLog(@"Value = %@",textField.text);
                    [cell.contentView addSubview:textField];
                    [self.fields addObject:textField];
                }
            }
        }
            break;

        case 4:
        {   
            if (cell == nil) 
            {
                cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:cellIdentifierF] autorelease];
                cell.backgroundColor = [[UIColor alloc]initWithPatternImage:[UIImage imageNamed:@"buttonbg-1.png"]];

                //Only add content to cell if it is new
                if([cellIdentifierF isEqualToString: fifthCellIdentifier])
                {
                    checkboxButton = [[[UIButton alloc] initWithFrame:CGRectMake(16,1,120, 44)]autorelease];
                    [checkboxButton setImage:[UIImage imageNamed:@"ewee.png"] forState:UIControlStateNormal];
                    [checkboxButton addTarget:self action:@selector(toggleButton:) forControlEvents:UIControlEventTouchUpInside];

                    NSString *one = reminderInstance.selString;
                    NSNumber* i = [NSNumber numberWithInt:[one intValue]];
                    BOOL isOn = [i boolValue];

                    if(isOn)
                    {
                        [checkboxButton setImage:[UIImage imageNamed:@"checkarrow.png"] forState:UIControlStateNormal];
                    }
                    else
                    {
                        [checkboxButton setImage:[UIImage imageNamed:@"ewee.png"] forState:UIControlStateNormal];
                    }            
                    NSLog(@"String Val = %@",one);

            [checkboxButton setContentHorizontalAlignment:UIControlContentHorizontalAlignmentLeft];
            [checkboxButton setImageEdgeInsets:UIEdgeInsetsMake(0.0, 0.0, 0.0, 0.0)];
            [cell addSubview:checkboxButton];
            UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(55, 10, 225, 24)];
            label.text = @"Every Year";
            label.textColor = [UIColor whiteColor];
            label.backgroundColor = [UIColor clearColor];
            [cell addSubview:label];
            cell.textLabel.textColor = [UIColor whiteColor];
            [label release];
                }
            }

        }
            break;

        case 5:
        {
            if (cell == nil) 
            {
                cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:cellIdentifierF] autorelease];
                cell.backgroundColor = [[UIColor alloc]initWithPatternImage:[UIImage imageNamed:@"buttonbg-1.png"]];

                //Only add content to cell if it is new
                if([cellIdentifierF isEqualToString: sixthCellIdentifier])
                {
                    textField.placeholder = @"Enter the number here";
                    [self.textField setValue:[UIColor purpleColor] 
                                    forKeyPath:@"_placeholderLabel.textColor"];
                    textField.text = num;
                    textField.text = reminderInstance.number;
                    textField.tag = 106; 
                    textField.userInteractionEnabled = YES;
                    textField.keyboardType = UIKeyboardTypeNumberPad;
                    NSLog(@"Value = %@",textField.text);
                    [cell.contentView addSubview:textField];
                    [self.fields addObject:textField];
                }
            }
        }
            break;

        case 6:
        {
            if (cell == nil) 
            {
                cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:cellIdentifierF] autorelease];
                cell.backgroundColor = [[UIColor alloc]initWithPatternImage:[UIImage imageNamed:@"reminderbuttonxl.png"]];

                //Only add content to cell if it is new
                if([cellIdentifierF isEqualToString: seventhCellIdentifier])
                {
                    cell.backgroundColor = [UIColor clearColor];
                    textView.clipsToBounds = YES;
                    textView = [[UITextView alloc]initWithFrame: CGRectMake(-2, -3, 307, 154)];
                    UIImageView *imgView = [[[UIImageView alloc]initWithFrame: textView.frame]autorelease];
                    imgView.image = [UIImage imageNamed: @"buttonbg_text.png"];
                    [textView addSubview: imgView];
                    [textView sendSubviewToBack: imgView];
                    textView.backgroundColor = [UIColor clearColor];
                    textView.delegate = self;
                    textView.tag = 11;
                    tagValues = textView.tag;
                    textView.textColor = [UIColor purpleColor];
                    [cell.contentView addSubview:textView];
                    textView.text = @"Your birthday wishes/other reminder body here";
                    NSLog(@"Value = %@",textView.text);
                }
            }
        }
            break;

        case 7:
        {
            if (cell == nil) 
            {
                cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:cellIdentifierF] autorelease];
                cell.backgroundColor = [[UIColor alloc]initWithPatternImage:[UIImage imageNamed:@"buttonbg-1.png"]];

                //Only add content to cell if it is new
                if([cellIdentifierF isEqualToString: eightCellIdentifier])
                {
                    textField.tag = 107;
                    textField.inputView = self.groupPicker;
                    tagValues = textField.tag;
                    textField.text = reminderInstance.remGroup;
                    NSLog(@"Value = %@",textField.text);
                    [cell.contentView addSubview:textField];
                    [self.fields addObject:textField];
                }
            }
        }
            break;

        default:
            break;
    }

    int size = [fields count];
    NSLog(@"there are %d objects in the array", size);

    return cell;
}

我已经多次尝试找出到底出了什么问题，我还检查了一些问题here和 there .但找不到任何有效/合适的。回答或解决我的问题。

所以请任何人帮助我提供有值(value)的建议或示例代码片段。

提前感谢大家:)

Answer 1

构建表单的方式会产生很多问题，这是有道理的(实际上就是这种情况)当我需要构建这样的表单时，我自己一直在做的是使用构建一个包含所有控件的普通 View (无论它有多长)并将该表单放在 ScrollView 中，并使用 View 的大小设置其内容大小在里面。这将使您能够更好地控制表单的外观。而且我认为我还没有见过使用表格 View 作为表单条目的应用程序。

你可以使用界面构建器来构建你的表单(只需欺骗 Xcode 并使主视图和 ScrollView 足够大，这样你就可以看到构建器上的所有内容，然后在完成后将其调整为适当的大小)