Question

我目前正在开发一个程序，可以从我的Core Data设置中动态填充选择器视图。我有一切都在数据方面工作，但我现在遇到的问题是在我的标签上格式化。

选择器在操作表中显示自己的工具栏，工具栏右侧有一个按钮。它的初始状态是可见2个刻度盘。按下按钮时，它会变为3个拨盘。

- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
{
    UILabel *pickerLabel = (UILabel *)view;

    CGSize limitSize = CGSizeMake(100.0f, 45.0f);
    CGSize textSize;
    CGRect labelRect;
    NSString *title = @"";


    switch (numberOfComponents){
        case 2:
        {
            ...gets strings from fetched data (varying length from 4 to 20+)
                    title = someString
        }
        case 3:
        {
            ...same as above but for the second set of data.
                    title = someString
        }           
    }


    textSize = [title sizeWithFont:[UIFont systemFontOfSize:14] constrainedToSize:limitSize lineBreakMode:UILineBreakModeWordWrap];
    labelRect = CGRectMake(0, 0, textSize.width, textSize.height);
    NSLog(@"length:%i title:%@",[title length],title);
    NSLog(@"h:%f w:%f",textSize.height,textSize.width);
    if (pickerLabel == nil)
    {
        pickerLabel = [[[UILabel alloc] initWithFrame:labelRect] autorelease];
        [pickerLabel setFont:[UIFont systemFontOfSize:14]];
        [pickerLabel setBackgroundColor:[UIColor clearColor]];
        [pickerLabel setLineBreakMode:UILineBreakModeWordWrap];
        [pickerLabel setTextAlignment:UITextAlignmentCenter];
        [pickerLabel setNumberOfLines:2];
    }

    [pickerLabel setText:title];    

    return pickerLabel;
}

我手动将行高设置为32.0f。我得到了非常奇怪的结果，第二个组件中的一些标签工作得很好。但其他人根本没有包装，有些只是显示为空白。

即：布鲁塞尔豆芽包好（右组分）。但牛奶和奶油不显示（只有牛奶可见）蔬菜根本没有出现。我的代码在哪里出错？

Answer 1

我设法让它表现得很好。我通过删除

更改了最后一部分


textSize = [title sizeWithFont:[UIFont systemFontOfSize:14] constrainedToSize:limitSize lineBreakMode:UILineBreakModeWordWrap];

我手动设置了框架


labelRect = CGRectMake(0,0,100.0,36.0);

不知道为什么这个有效，而动态大小没有。

Answer 2

这是swift的版本。

 func pickerView(pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusingView view: UIView!) -> UIView {
    var label : UILabel
    if view == nil {
        label = UILabel(frame: CGRect(x: 0, y: 0, width: 0, height: UIFont.systemFontOfSize(UIFont.systemFontSize()).lineHeight * 2 * UIScreen.mainScreen().scale))
        label.textAlignment = NSTextAlignment.Center
        label.numberOfLines = 2
        label.lineBreakMode = NSLineBreakMode.ByWordWrapping
        label.autoresizingMask = UIViewAutoresizing.FlexibleWidth
    } else {
        label = view as UILabel
    }
    label.text = line1 + "\n" + line2

    return label;
}

func pickerView(pickerView: UIPickerView, rowHeightForComponent component: Int) -> CGFloat {
    return UIFont.systemFontOfSize(UIFont.systemFontSize()).lineHeight * 2 * UIScreen.mainScreen().scale
}

Answer 3

我更正了您的代码，以便让标签宽度适合选择器宽度。我使用了koushi方法。它现在运作得很好。请参阅此处附录的代码。

 - (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
 {

//assegna i nomi alle caselle del picker e assegna anche la dimensione del font e del rettangolo che contiene le scritte

UILabel *pickerLabel = (UILabel *)view;
CGRect labelRect;

NSString *title=@"";
switch (numberOfComponents){
case 2:
{
    ...gets strings from fetched data (varying length from 4 to 20+)
                title = someString
}
case 3:
{
    ...same as above but for the second set of data.
                title = someString
}           
 }

CGFloat labelWidth=pickerView.frame.size.width-50;
labelRect = CGRectMake( 0,0,labelWidth,45.0);

if (pickerLabel == nil)
{
    pickerLabel = [[UILabel alloc] initWithFrame:labelRect];
    [pickerLabel setFont:[UIFont systemFontOfSize:16]];
    [pickerLabel setBackgroundColor:[UIColor clearColor]];
    [pickerLabel setNumberOfLines:2];
}

[pickerLabel setText:title];    
return pickerLabel;

  }

关于您的原始代码：我认为拥有不同矩形元素的选择器不利于外观（用户体验）问题。我怀疑不同的标签rect大小正在解决代码中的问题。如果您要显示的文本可能比定义的rect更大，我认为您应该使用不同的应用程序结构方法。

注意：在我的应用程序中，我使用picker标签属性来识别选择了哪个选择器，因为我的视图中有多个选择器。出于这个原因，我使用以下代码替换了代码中的“switch”语句：

  if (pickerView.tag==1)
    title= globalSubcategoryArray[row];
  else
    title= globalAreasName[row];

显然我也补充说：

 -(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
if (pickerView.tag==1)
    return globalSubcategoryArray.count;
else    
    return globalAreasName.count;
 }

 -(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
return  1;
 }



 -(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
if (pickerView.tag==1){
    self.subcategoryTextview.text = globalSubcategoryArray[row];
    globalSelectedSubcategoryIndex=row;
    [self.subcategoryTextview resignFirstResponder];

}else{
    self.areaTextview.text= globalAreasName[row];
    globalSelectedAreaIndex=row;
    [self.areaTextview resignFirstResponder];
}

 }

UIPickerView与Multiline UILabel

3 个答案: