Question

I want to create a picker that looks and works like the country select field of itune store account. Here is what I am talking about.

http://i38.tinypic.com/5p0w91.jpg

This picker doesn t have a row highlighted. It has "correct" sign marked in front of selected row. user can scroll this picker and then select the row so "correct" sign will appear in front of newly selected row. Can someone please help?

Answer 1

这一点可以比较容易地利用带有习俗成分观点的选子来实现。利用实例变量跟踪你选定的行文,并相应改变你的标识。如果你想要列入检查标记,那么你需要走一步,使用“IDView”的门槛,而不是简单的“IDLabel”。


@interface ViewContainingPicker
{
    NSUInteger mySelectedRow;
}
@end

@implementation ViewContainingPicker

// Init, Picker setup, etc
- (UIPickerView *)myPickerView
{
    // Create picker, set mySelectedRow to NSNotFound
    mySelectedRow = NSNotFound;
    return myPickerView;
}

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

    if (nil == label) {
        UILabel *label = [[[UILabel alloc] initWithFrame:CGRectMake(0, 0, PICKER_WIDTH, PICKER_ROW_HEIGHT)] autorelease];
    }

    label.text = @"Label for this row";

    // Selected Row will be blue
    if (row == mySelectedRow) {
        label.textColor = [UIColor blueColor];
    } else {
        label.textColor = [UIColor blackColor];
    }

    return label;
}

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
    // Just set selected component and reload, color will change in dataSource pickerView:viewForRow:forComponent:reusingView:
    mySelectedRow = row;
    [pickerView reloadComponent:component];
}

Answer 2

我不熟悉编码系统,而对于以浏览器为基础的电子数据系统(Safari)来说,你只是使用一种简单的下降菜单:

<select>
<option>Country 1</option>
<option>Country 2</option>
...
<option>Country N</option>
</select>

无论哪一种东西都一样,都应当做到同样。

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