XLForm - 如何根据另一行的值隐藏一行

Question

我可能需要一些帮助。

我在我的Objective-C项目中使用XLForm。我有第一行，有一个选择器，你有四个不同的选项。然后是第二个选择器。但是，仅当在第一个选取器中选择了某个值时，第二个选取器才应可用。

我知道github网站上有一个描述，但我真的不知道该怎么做。所以请帮我做这件事。

以下是我的代码的相关部分：

row = [XLFormRowDescriptor formRowDescriptorWithTag:@"repeat" rowType:XLFormRowDescriptorTypeSelectorPickerViewInline title:@"Wiederholen:" ];
row.cellClass = [LehrerXLFormInlineSelectorCell class];
NSMutableArray *selectionArray = [NSMutableArray array];
for (NSNumber *item in [APIDataReplacement appointmentRepeatingList]) {
    NSString *title = [APIDataReplacement appointmentRepeatingToString:item.intValue];
    [selectionArray addObject:[XLFormOptionsObject formOptionsObjectWithValue:item displayText:title]];
}
row.selectorOptions = selectionArray;
if ([selectionArray count] == 0) {
    [row setDisabled:@YES];
}
if (aItem) {
    int repeatingID = [[aItem appointmentRepeatingId] intValue];
    NSString *title = [APIDataReplacement appointmentRepeatingToString:repeatingID];
    row.value = [XLFormOptionsObject formOptionsObjectWithValue:[NSNumber numberWithInt:repeatingID] displayText:title];
}else{
    NSNumber *first = [[APIDataReplacement appointmentRepeatingList] firstObject];
    NSString *title = [APIDataReplacement appointmentRepeatingToString:first.intValue];
    row.value = [XLFormOptionsObject formOptionsObjectWithValue:first displayText:title];
}
[section addFormRow:row];

section = [XLFormSectionDescriptor formSectionWithTitle:@""];
[form addFormSection:section];

row = [XLFormRowDescriptor formRowDescriptorWithTag:@"weekday" rowType:XLFormRowDescriptorTypeSelectorPickerViewInline title: @"Wochentag:"];
row.cellClass = [LehrerXLFormInlineSelectorCell class];
NSMutableArray *selectionArray1 = [NSMutableArray array];
for (NSNumber *item in [APIDataReplacement dayList]) {
    NSString *title = [APIDataReplacement dayToString:item.intValue];
    [selectionArray1 addObject:[XLFormOptionsObject formOptionsObjectWithValue:item displayText:title]];
}
row.selectorOptions = selectionArray1;
if (aItem) {
    // AppointmentRepeating *currentRepeat = [aItem appointmentRepeating];
    int dayID = [[aItem startday] intValue];
    NSString *title = [APIDataReplacement dayToString:dayID];
    row.value = [XLFormOptionsObject formOptionsObjectWithValue:[NSNumber numberWithInt:dayID] displayText:title];
}else{
    NSNumber *first = [[APIDataReplacement dayList] firstObject];
    NSString *title = [APIDataReplacement dayToString:first.intValue];
    row.value = [XLFormOptionsObject formOptionsObjectWithValue:first displayText:title];
}
[section addFormRow:row];

section = [XLFormSectionDescriptor formSectionWithTitle:@""];
[form addFormSection:section];

这是两个选择器。我想我应该在形式上做一些事情 RowDescriptorValueHasChanged-方法，但我不知道是什么。如果第一个选取器的值为"20"，则应隐藏第二个选取器。

非常感谢您的帮助。

Answer 1

对于您的第二个XLFormRowDescriptor，您应该：

secondRow.hidden = [NSString stringWithFormat:@"$%@ == 20", firstRow];

firstRow是第一个XLFormRowDescriptor.

这实际上创建了一个 NSPredicate，每当值更改时都会自动评估该 NSPredicate，并适当地设置可见性。

取自XLForm的例子：

例如，可以将以下字符串设置为行（秒）到 使其在上一行（第一行）包含值时消失 "隐藏"。

second.hidden = [NSString stringWithFormat:@"$%d contains[c] 'hide'", [first.value intValue]];

编辑：我更改了谓词以使用 NSNumber 值。