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[英]How can I determine the area currently visible in a scrollview and determine the center?
[英]How to determine how many `NavigationSplitView` columns are visible?
NavigationSplitView
,可見的列數可能因設備(macOS、iPhone、iPad)以及它是否使用分屏(iPad 可以同時運行 2 個應用程序)而異。NavigationSplitView
中如何確定有多少列可見?提問原因:我有一個 sidebarList、contentList 和 detailList。 現在我想根據可見的列數選擇不同的單元格
struct ContentView: View {
@State private var departments = ["D1"]
@State private var employees = ["E1", "E2", "E3"]
@State private var selectedDepartment: String?
@State private var selectedEmployee: String?
var body: some View {
NavigationSplitView {
List(departments, id: \.self, selection: $selectedDepartment) { department in
Text(department)
}
} content: {
List(employees, id: \.self, selection: $selectedEmployee) { employee in
Text(employee)
}
} detail: {
if let selectedEmployee {
Text(selectedEmployee)
} else {
Text("No employee selected")
}
}
}
}
您可以在初始化程序中使用 NavigationSplitViewVisibility 結構。
@State private var columnVisibilty: NavigationSplitViewVisibility = .all
這將是 3 列設計的示例。 通過讀取或更改 state 變量,您可以控制它。 (因此綁定,系統設置它當前顯示的內容)為清楚起見添加
NavigationSplitView(columnVisibility: $columnVisibilty) sidebar: {
...
} content: {
...
} detail: {
...
}
這是蘋果文檔的鏈接: https://developer.apple.com/documentation/swiftui/navigationsplitviewvisibility
添加了粗略的示例:
struct ContentView: View {
@State private var columnVisibility: NavigationSplitViewVisibility = .all
var body: some View {
NavigationSplitView(columnVisibility: $columnVisibility) {
Text("Sidebar:")
.toolbar {
Button("Print") {
print(columnVisibility)
}
}
} content: {
Text("Content:")
.toolbar {
Button("Print") {
print(columnVisibility)
}
}
} detail: {
Text("Detail:")
.toolbar {
Button("Print") {
print(columnVisibility)
}
}
}
}
}
這讓我可以設置一個初始設置,但它會根據 SplitView 的當前狀態進行更新。 只需按下打印按鈕,您就可以看到更改。
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