UITableViewCell中UILabel宽度的动态计算 [英] dynamic calculation of UILabel width in UITableViewCell

问题描述

我正在基于UITableViewCellStyle1（等等）构建一个自定义的应用程序内设置视图。

我正在尝试动态计算单元格的左标签（标题）的宽度，以确定右边文本字段的宽度可以是多少。

当我在模拟器中启动应用程序并加载视图时，标题标签的宽度为零，直到我向下滚动视图，并且单元格不可见，然后当我滚动回尺寸按预期调整。我相信这可能需要做细胞再利用的事情。

我需要单元格中的标题标签，以便在视图加载时具有正确的宽度，而不是在一次看不见之后。

$ b （UITableViewCell *）tableView：（UITableView *）tableView cellForRowAtIndexPath :( NSIndexPath *）indexPath
{
static NSString * reuseIdentifier = @SettingsCell;

UITableViewCell * cell = [tableView dequeueReusableCellWithIdentifier：reuseIdentifier];

if（！cell）
{
cell = [[[UITableViewCell alloc] initWithStyle：UITableViewCellStyleValue1 reuseIdentifier：reuseIdentifier] autorelease];
[cell setBackgroundColor：[UIColor baeDarkGrayColor]];


UILabel * cellLabel = [cell textLabel];
[cellLabel setTextColor：[UIColor whiteColor]];
[cellLabel setBackgroundColor：[UIColor clearColor]];

[cell setUserInteractionEnabled：YES];
[cell setSelectionStyle：UITableViewCellSelectionStyleGray];
}

//使用相应的数据填充单元格。
NSDictionary * tableSection = [_tableData objectAtIndex：indexPath.section];

//设置标签
UILabel * textLabel = [cell textLabel];
NSString * labelString = [[tableSection objectForKey：@itemTitles] objectAtIndex：indexPath.row];
[textLabel setText：labelString];

// CGSize constrainedSize;
// constrainedSize.width = MAXFLOAT;
// constrainedSize.height = MAXFLOAT;

CGSize textLabelSize = [textLabel.text sizeWithFont：textLabel.font / * constrainedToSize：constrainedSize * /];

NSLog（@text label width：％f，textLabelSize.width）;


//设置附件视图
BAESettingsTableCellAccessoryType accessoryType = [[[tableSection objectForKey：@itemAccessories] objectAtIndex：indexPath.row] integerValue];
switch（accessoryType）
{
case BAESettingsTableCellAccessoryDisclosureIndicator：
{
UIImageView * disclosureView = [[UIImageView alloc] initWithImage：[UIImage imageNamed：@AccessoryDisclosure.png ]];
[cell setAccessoryView：disclosureView];
[disclosureView release];
break;
}
case BAESettingsTableCellAccessoryOnOffSwitch：
{
UISwitch * onOffSwitch = [[UISwitch alloc] initWithFrame：CGRectZero];
[onOffSwitch setOn：YES];
[cell setAccessoryView：onOffSwitch];
[onOffSwitch release];
break;
}
case BAESettingsTableCellAccessoryNone：
//默认值：
// break;
{

CGRect cellFrame = [cell frame];

float detailTextFieldWidth = cellFrame.size.width - （textLabelSize.width + 50）;
float detailTextFieldHeight = cellFrame.size.height - 1;

NSLog（@详细文本字段计算的框架宽度，高度，％f，％f，detailTextFieldWidth，detailTextFieldHeight）;


CGRect框架= CGRectMake（cellFrame.origin.x，cellFrame.origin.y，detailTextFieldWidth，detailTextFieldHeight）;


UITextField * textField = [[UITextField alloc] initWithFrame：frame];
NSString * detailLabelString = [[tableSection objectForKey：@itemDetailStrings] objectAtIndex：indexPath.row];
textField.text = detailLabelString;
textField.textColor = cell.detailTextLabel.textColor;
textField.textAlignment = UITextAlignmentRight;
textField.borderStyle = UITextBorderStyleRoundedRect;
[cell setAccessoryView：textField];
[textField release];
break;
}

}

返回单元格;
}

解决方案

明确设置字体可以解决您的问题。

  CGSize textLabelSize = [textLabel.text sizeWithFont：[UIFont systemFontOfSize：17]]; 
  

Gory Detals：

当第一个由于字体大小为0，此代码段返回零宽度。

  [textLabel.text sizeWithFont：textLabel.font] 
  

我通过显示单元格字体的点大小来计算出来。

  NSLog（@font size：％f，cell.textLabel.font.pointSize）; 
  

点数大小为零，直到单元格关闭屏幕并返回，正如您所描述的那样。 / p>

I am building a custom, in-application settings view based on UITableViewCellStyle1 (or so).

I am trying to dynamically calculate the width of the left label (title) of a cell to determine how wide my text field on the right can be.

When I launch the app in the simulator and the view loads, the width of the title labels is zero until I scroll down the view and a cell is not visible, then when I scroll back up the size adjusts as expected. I believe this might have to do something with cell reusage.

I need the title labels in the cells to have their correct width when the view loads, not after they have gone out of sight one time.

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

UITableViewCell* cell = [tableView dequeueReusableCellWithIdentifier:reuseIdentifier];

if ( !cell )
{   
    cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:reuseIdentifier] autorelease];
    [cell setBackgroundColor:[UIColor baeDarkGrayColor]];


    UILabel* cellLabel = [cell textLabel];
    [cellLabel setTextColor:[UIColor whiteColor]];
    [cellLabel setBackgroundColor:[UIColor clearColor]];

    [cell setUserInteractionEnabled:YES];
    [cell setSelectionStyle:UITableViewCellSelectionStyleGray];
}

// Populate cell with corresponding data.
NSDictionary* tableSection = [_tableData objectAtIndex:indexPath.section];

// Set the label
UILabel* textLabel = [cell textLabel];
NSString* labelString = [[tableSection objectForKey:@"itemTitles"] objectAtIndex:indexPath.row];
[textLabel setText:labelString];

   //   CGSize constrainedSize;
  //    constrainedSize.width = MAXFLOAT;
 // constrainedSize.height = MAXFLOAT;

CGSize textLabelSize = [textLabel.text sizeWithFont:textLabel.font /*constrainedToSize:constrainedSize*/];

NSLog(@"text label width: %f", textLabelSize.width);    


// Set the accessory view
BAESettingsTableCellAccessoryType accessoryType = [[[tableSection objectForKey:@"itemAccessories"] objectAtIndex:indexPath.row] integerValue];
switch ( accessoryType )
{
    case BAESettingsTableCellAccessoryDisclosureIndicator:
    {
        UIImageView* disclosureView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"AccessoryDisclosure.png"]];
        [cell setAccessoryView:disclosureView];
        [disclosureView release];
        break;
    }
    case BAESettingsTableCellAccessoryOnOffSwitch:
    {
        UISwitch* onOffSwitch = [[UISwitch alloc] initWithFrame:CGRectZero];
        [onOffSwitch setOn:YES];
        [cell setAccessoryView:onOffSwitch];
        [onOffSwitch release];
        break;
    }
    case BAESettingsTableCellAccessoryNone:
        // default:
        // break;
    {

        CGRect cellFrame = [cell frame];

        float detailTextFieldWidth = cellFrame.size.width - ( textLabelSize.width + 50 );
        float detailTextFieldHeight = cellFrame.size.height - 1;

        NSLog(@"detail text field calculated frame width, height, %f, %f", detailTextFieldWidth, detailTextFieldHeight);


        CGRect frame = CGRectMake(cellFrame.origin.x, cellFrame.origin.y, detailTextFieldWidth, detailTextFieldHeight);


        UITextField* textField = [[UITextField alloc] initWithFrame:frame];
        NSString* detailLabelString = [[tableSection objectForKey:@"itemDetailStrings"] objectAtIndex:indexPath.row];
        textField.text = detailLabelString;
        textField.textColor = cell.detailTextLabel.textColor;
        textField.textAlignment = UITextAlignmentRight;
        textField.borderStyle = UITextBorderStyleRoundedRect;
        [cell setAccessoryView:textField];
        [textField release];
        break;
    }

}

return cell;
   }

解决方案

Explicitly setting the font solves your problem.

CGSize textLabelSize = [textLabel.text sizeWithFont:[UIFont systemFontOfSize:17]];

Gory Detals:
When the tableview first loads, this snippet returns zero width due to the font size being 0.

[textLabel.text sizeWithFont:textLabel.font]

I figured this out by displaying the point size of the cell font.

NSLog(@"font size: %f", cell.textLabel.font.pointSize);

The point size was zero until the cell went off screen and came back, just as you described.

这篇关于UITableViewCell中UILabel宽度的动态计算的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！