SwiftUI Positioning View [duplicate] - swift

Question

I've seen similar questions like this one here on Stack Overflow, but none of them have been able to answer my question.
I have created a List, but I want to remove the padding space (marked with a red arrow) above the content in the List. How can I remove it when using a GroupedListStyle?
This is a List within a VStack within a NavigationView that is displayed via fullscreenCover:
var body: some View {
NavigationView {
VStack {
taskEventPicker
myList
}
.navigationBarTitle("Add Task", displayMode: .inline)
}
}
where taskEventPicker is a segmented Picker (boxed in green):
var taskEventPicker: some View {
Picker("Mode", selection: $selection) { /* ... */ }
.pickerStyle(SegmentedPickerStyle())
.padding()
}
and myList is the form in question (boxed in yellow):
var myList: some View {
List { /* ... */ }
.listStyle(GroupedListStyle())
}
What I've Tried
Removing the header of the list
Hiding the Navigation Bar title
Setting UITableView.appearance().tableHeaderView to an empty frame
Attempting UITableView.appearance().contentInset.top = -35
Setting listRowInsets (this affects all list rows)
Note: I'm looking for an answer that can apply to the GroupedListStyle. I understand that this issue does not occur with PlainListStyle. This padding issue also occurs with the default listStyle.
Thanks for the help!
Xcode version: 12.5

Answer 1

Firstly, I would say that GroupedListStyle is working as intended.
On iOS, the grouped list style displays a larger header and footer
than the plain style, which visually distances the members of
different sections.
You say you have tried this, but it does work for me (Xcode 12.5.1):
List { ... }
.onAppear(perform: {
UITableView.appearance().contentInset.top = -35
})
You could also hide the list header, by using a ZStack with the List at the bottom of the stack and the Picker over the top. The Picker does have transparency, so you would also have to add an opaque view to act as background for the Picker.
var body: some View {
NavigationView {
ZStack(alignment: .top) {
List { ... }
.listStyle(.grouped)
.padding(.top, 30)
Color.white
.frame(height: 65)
Picker { ... }
.pickerStyle(.segmented)
.padding()
}
.navigationBarTitle("Add Task", displayMode: .inline)
}
}
As far as I can see this just appears the same as PlainListStyle would do, but I assume you have a particular reason for wanting to use GroupedListStyle.

Answer 2

The contentInsent part of the accepted answer works perfectly fine unless for instance as in my case, at the end of a navigation stack you want to use it in some detail view containing a List with navigationBarTitleDisplayMode set to .inline. When navigating back in the stack to a view using another List with navigationBarTitleDisplayMode set to .large, the List content and NavigationBar interlace awfully. And they probably might as well do whatever the navigationBarTitleDisplayMode is set to.
Switching to listStyle(.plain) in my case isn't a feasable option, because then in the detail view, I loose the beautifully animated built-in transitions to and from List's EditMode, that seem to exist only in the grouped listStyle varieties.
Finally, after quite a few days of frustration I figured out that tableHeaderView is the approach that works best for my problem - and of course, it works just as well to solve the original question. It's all in here ...:
XCode documentation
... and in this sentence:
"When assigning a view to this property [i.e. tableHeaderView], set the height of that view to a nonzero value"
So I do like:
List {
// bla bla bla
}
.listStyle(.grouped)
.onAppear {
let tableHeaderView = UIView(frame: .zero)
tableHeaderView.frame.size.height = 1
UITableView.appearance().tableHeaderView = tableHeaderView
}
It's as simple as that. Hope it might help you, too!

Answer 3

Give a header to the first section in your list: Section(header: Spacer(minLength: 0))
Disclaimer: this doesn't totally remove the top spacing, but it does yield the same result as the native Settings app.
Note: This worked for me on iOS 14.5
VStack {
List {
Section(header: Spacer(minLength: 0)) {
Text(verbatim: "First Section")
}
Section {
Text(verbatim: "Second Section")
}
}
.listStyle(GroupedListStyle())
}

Answer 4

Another option is to add
List { ... }.offset(x: 0, y: -30).edgesIgnoringSafeArea(.bottom)
to the List. Since you won't be able to scroll all the way up when using this add a Spacer(minLength: 30) at the very bottom of the List.

Answer 5

I had a similar setup where I had some views and a List in a VStack and I had an undesired space that appeared on the top of my List. In my case I needed to set the VStack spacing to 0 and that solved the issue because it was actually just spacing from the VStack.
VStack(spacing: 0) { ... }

Answer 6

my 2 cents. I arrived here for the same reason.
take a look at:
https://developer.apple.com/forums/thread/662544
it' seems the correct approach.

Answer 7

extension View {
/// Clear tableview and cell color
func tableClearColor() {
let tableHeaderView = UIView(frame: .zero)
tableHeaderView.frame.size.height = 0.5
UITableView.appearance().tableHeaderView = tableHeaderView
}
}