How to change the background color for a Form in SwiftUI?

问题

I wanna change that "light gray" background color for a form, but .foregroundColor(Color.blue) and .background(Color.blue) does not seem to work

struct ContentView : View {

 @State var value = ""

    var body: some View {
        Form {
            Section(header: Text("First Name")) {
                TextField($value)
            }
            Section(header: Text("Last Name")) {
                TextField($value)
            }
        }.foregroundColor(Color.blue)

    }
}

回答1:

A Working Solution:

All SwiftUI's Lists are backed by a UITableViewin iOS. so you need to change the background color of the tableView. But since Color and UIColor values are slightly different, you can get rid of the UIColor.

struct ContentView: View {
    
    init(){
        UITableView.appearance().backgroundColor = .clear
    }
    
    @State var value = ""
    
    var body: some View {
        Form {
            Section(header: Text("First Name")) {
                TextField("First Name", text: $value)
            }
            Section(header: Text("Last Name")) {
                TextField("Last Name", text: $value)
            }
        }
        .foregroundColor(Color.blue)
        .background(Color.yellow)
    }
}

Now you can use Any background (including all Colors) you want

Note that those top and bottom white areas are safe are and you can use .edgesIgnoringSafeArea() modifier to get rid of them.

---

Restore

Since UITableView.appearance().backgroundColor applies globally, you can use .onAppear modifier to change it in different views (since it is a global change). So you can use another onAppear or onDisappear to reset it back to what you want.

And the default colors are:

UIColor.systemGroupedBackground for the grouped style. And

UIColor.systemBackground for the plain style.

And they both have automatic support for both dark mode and light mode.

回答2:

try this

.onAppear {
   UITableView.appearance().backgroundColor = .blue
}

回答3:

The accepted answer by Mojtaba Hosseini, above, works but the init() statement is not a good place for the UITableView statement. This is because it "hard codes" the ContentView's init parameters. In this case it has none so everything works but if an @ObservedObject was added to the view then this would break the init function.

Much simpler just to add the UITable statement to the body, explicitly return the Form and delete the init().

var body: some View {
    UITableView.appearance().backgroundColor = .clear
    return Form {...}
 }

However, setting the background colour on the Form usually works as expected. The fact that it is not working on the ContentView screen may be a bug.

回答4:

If you don't want to modify safe area of the Form, you can use ZStackas well:

struct ContentView: View {
    
    init(){
        
        UITableView.appearance().backgroundColor = .clear
    }
    
    @State var value = ""
    
    var body: some View {
        ZStack {
            Color(UIColor.systemYellow)
                .edgesIgnoringSafeArea(.all)
            Form {
                Section(header: Text("First Name")) {
                    TextField("First Name", text: $value)
                }
                Section(header: Text("Last Name")) {
                    TextField("Last Name", text: $value)
                }
            }
        }
    }
}

回答5:

The solutions above didn't really work for what I was trying to achieve. I wanted an initial screen with a clear background for the form, and subsequent screens to have the default iOS systemGroupedBackground color. Using appear() and disappear() didn't work for me as switching between various tabs was leading to bugs in the appearance.

I came up with the following solution. It borrows from the solutions above.

For my ContentView screen, I inserted this code just inside the Struct.

init(){
    UITableView.appearance().backgroundColor = .clear
}

This is a global change that affects all forms.

For all forms where I wanted the default color to work, I inserted this code just outside the Form {}.

.background(Color(.systemGroupedBackground))

来源：https://stackoverflow.com/questions/57254461/how-to-change-the-background-color-for-a-form-in-swiftui