ios - 将按钮数组添加到适当的表行

Question

我正在尝试动态地用多行按钮填充表格。当表格启动时，我向它传递一个包含正确按钮的数组。按钮的数量以及行的数量会有所不同。这是有效的，直到我需要创建一个新行(即太多按钮无法容纳在第一行)。假设我将它限制为每行 4 个按钮。然后我的按钮从第 2 行开始，而不是像应有的那样从第 1 行开始。它们也会被剪裁在正确的边界上。

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    NSInteger rows = 0;  // No rows if section is unknown!
    switch (section)
    {
        case TableViewSectionFormatButtons:
        {
            if ([[self fileTypeButtonsArray] count] % kButtonsPerRow)
                return ([[self fileTypeButtonsArray] count] / kButtonsPerRow) + 1;
            else
                return [[self fileTypeButtonsArray] count] / kButtonsPerRow;
        }
            break;
        case TableViewSectionExportSwitches:
            rows = 4;
            break;
        case TableViewSectionExportButton:
            rows = 1;
            break;
        default:
            break;
    }

    return rows;
}

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

    UITableViewCell *cellToReturn = nil;

    // Usage note: Both kinds of cells get created every time, which is arguably wasteful.  Since there aren't many rows involved
    // it's simpler just to ignore the one that we don't need.  Assign the one we want to cellToReturn.

    UITableViewCell *defaultCell = [tableView dequeueReusableCellWithIdentifier:defaultCellIdentifier]; // Image on left
    if (defaultCell == nil) {
        defaultCell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:defaultCellIdentifier];
    }

    UITableViewCell *detailCell = [tableView dequeueReusableCellWithIdentifier:detailCellIdentifier]; // Text on right
    if (detailCell == nil) {
        detailCell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:detailCellIdentifier];
    }

    // Clear old values
    defaultCell.textLabel.textAlignment = NSTextAlignmentLeft;
    defaultCell.accessoryType = UITableViewCellAccessoryNone;
    defaultCell.accessoryView = nil;
    defaultCell.imageView.image = nil;

    detailCell.accessoryType = UITableViewCellAccessoryNone;
    detailCell.imageView.image = nil;


    switch (indexPath.section) {
        case TableViewSectionFormatButtons: {

            for (int i = 0; i < [self.fileTypeButtonsArray count]; i++)
            {
                UIButton *currentButton = (UIButton *)[self.fileTypeButtonsArray objectAtIndex:i];
                [currentButton setTag:i];

                [currentButton setFrame:CGRectMake((kButtonPadding + (i * (kButtonWidth + kButtonPadding))), kButtonPadding, kButtonWidth, kButtonHeight)];
                [defaultCell.contentView addSubview:currentButton];
            }

            defaultCell.selectionStyle = UITableViewCellSelectionStyleNone;



            cellToReturn = defaultCell;
        }
            break;

        case TableViewSectionExportSwitches: {

            defaultCell.selectionStyle = UITableViewCellSelectionStyleNone;

            if (indexPath.row == 0) {
                defaultCell.textLabel.text = NSLocalizedString(@"synopsisSwitchLabel", @"Synopsis - Export switch label to indicate if Synopsis text should be included in export.");
                self.synopsisSwitch = [[UISwitch alloc] initWithFrame:CGRectZero];
                defaultCell.accessoryView = self.synopsisSwitch;
//                self.synopsisSwitch.on = [[NSUserDefaults standardUserDefaults] boolForKey:kUserDefaultsShowNotesIndicatorKey];

                [self.synopsisSwitch addTarget:self action:@selector(synopsisSwitchValueChanged:) forControlEvents: UIControlEventValueChanged];

            }

            else if (indexPath.row == 1)
            {
                defaultCell.textLabel.text = NSLocalizedString(@"bodySwitchLabel", @"Body - Export switch label to indicate if Body text should be included in export.");
                self.bodySwitch = [[UISwitch alloc] initWithFrame:CGRectZero];
                defaultCell.accessoryView = self.bodySwitch;

//                self.bodySwitch.on = [[NSUserDefaults standardUserDefaults] boolForKey:kUserDefaultsShowNotesIndicatorKey];
                [self.bodySwitch addTarget:self action:@selector(bodySwitchValueChanged:) forControlEvents: UIControlEventValueChanged];
            }

            else if (indexPath.row == 2)
            {
                defaultCell.textLabel.text = NSLocalizedString(@"notesSwitchLabel", @"Notes - Export switch label to indicate if Notes should be included in export.");

            self.notesSwitch = [[UISwitch alloc] initWithFrame:CGRectZero];
                defaultCell.accessoryView = self.notesSwitch;

//                self.notesSwitch.on = [[NSUserDefaults standardUserDefaults] boolForKey:kUserDefaultsShowExpandedOutlineKey];
                [self.notesSwitch addTarget:self action:@selector(notesSwitchValueChanged:) forControlEvents: UIControlEventValueChanged];
            }

            else if (indexPath.row == 3)
            {
                defaultCell.textLabel.text = NSLocalizedString(@"imagesSwitchLabel", @"Images - Export switch label to indicate if Images should be included in export.");
                self.imagesSwitch = [[UISwitch alloc] initWithFrame:CGRectZero];
                defaultCell.accessoryView = self.imagesSwitch;

//                self.imagesSwitch.on = [[NSUserDefaults standardUserDefaults] boolForKey:kUserDefaultsStoryboardModeKey];
                [self.imagesSwitch addTarget:self action:@selector(imagesSwitchValueChanged:) forControlEvents: UIControlEventValueChanged];
            }

            cellToReturn = defaultCell;
        }
            break;

        case TableViewSectionExportButton:
        {
            defaultCell.textLabel.textAlignment = NSTextAlignmentCenter;
            if (indexPath.row == 0)
            {
                defaultCell.textLabel.text = NSLocalizedString(@"nextButtonTitle", @"Next - Button title indicating user is ready to proceed with Export.");
                defaultCell.textLabel.textColor = [UIColor blueColor];
            }

            cellToReturn = defaultCell;
        }
            break;

    }

    return cellToReturn;
}

示例按钮超过 1 行 - 错误

示例按钮适合 1 行 - 好

我意识到我只是告诉它继续在彼此的右侧添加按钮。我很困惑如何告诉它要将它们放入哪些行。也很困惑为什么它们从第二行(索引 1)而不是顶行(索引 0)开始。感谢您的帮助。

Answer 1

在 numberOfRowsInSection: 方法中，您的 TableViewSectionFormatButtons: 如果按钮正好适合该行，则附加一行，即 if ([[self fileTypeButtonsArray]计数] % kBu​​ttonsPerRow);但这听起来与您想要做的完全相反。如果您的按钮无法整齐地放在其上方的行中，这听起来好像您只想添加一个额外的行，在这种情况下，我建议用一行代替:

case TableViewSectionFormatButtons: {
    return ([[self fileTypeButtonsArray] count] + kButtonsPerRow - 1) / kButtonsPerRow;
}

简单地将整数除法四舍五入。

至于您的 cellForRowAtIndexPath: 方法，(1) 您需要考虑每行的按钮数量，即在您的算法中包含 kButtonsPerRow，(2) 您需要知道您要添加到哪一行，并且 (3) 使用该信息您只想将属于当前行的按钮放在该当前行中，因此您不希望该循环从 0 开始然后继续一直到按钮数组的末尾。例如:

case TableViewSectionFormatButtons: {

    // Calculate the index of the first button in the current row
    int firstButtonIndex = indexPath.row * kButtonsPerRow;

    // Then starting from that index place kButtonsPerRow within that row
    for (int i = firstButtonIndex ; i < firstButtonIndex + kButtonsPerRow ; i++) {

        if (self.fileTypeButtonsArray.count > i) {
            UIButton *currentButton = (UIButton *)[self.fileTypeButtonsArray objectAtIndex:i];
            [currentButton setTag:i];
            [currentButton setFrame:CGRectMake((kButtonPadding + ((i-firstButtonIndex) * (kButtonWidth + kButtonPadding))), kButtonPadding, kButtonWidth, kButtonHeight)];
            [defaultCell.contentView addSubview:currentButton];
        }
    }

    defaultCell.selectionStyle = UITableViewCellSelectionStyleNone;
    cellToReturn = defaultCell;
}

类似的东西应该可以工作。

附言事实上，在每个 cellForRowAtIndexPath: 期间，您都重复使用单元格并将按钮添加为 subview ，这可能会导致一些问题。如果您要按照您在代码中已经完成的方式清除旧值，也许您还应该删除同一个地方的旧按钮，例如:

// Clear old values
defaultCell.textLabel.textAlignment = NSTextAlignmentLeft;
defaultCell.accessoryType = UITableViewCellAccessoryNone;
defaultCell.accessoryView = nil;
defaultCell.imageView.image = nil;

for (UIView *view in [defaultCell subviews]) {
    if ([view isKindOfClass:[UIButton class]]) {
        [view removeFromSuperview];
    }
}