Question

我学习了如何在swiftUI中创建类似UIKit tabBar的tabBar。我想将中间的tabItem移到顶部。有什么办法可以实现？

TabView代码

TabView {
        ViewTasks()
            .tabItem {
                Image(systemName: "list.bullet.below.rectangle")
                Text("View Tasks")
        }
        AddTask()
            .tabItem {
                Image(systemName: "plus.circle").font(.system(size: 60))
        }
        CategoriesTasks()
            .tabItem {
                Image(systemName: "square.grid.2x2")
                Text("Categories")
        }
    }

视觉示例

Answer 1

第一个想法是使用ZStack，以便您可以用自己的可点击图像覆盖tabItem。这是示例：

struct TabViewModel: View {

    @State var showActionSheet: Bool = false

    var body: some View {


        ZStack {
            GeometryReader { geometry in
                TabView {

                            Text("list")
                                .tabItem {
                                    Image(systemName: "list.bullet.below.rectangle")
                            }

                            Text("plus")
                                .tabItem {
                                    Text(" ")
                            }

                            Text("categories")
                                .tabItem {
                                    Image(systemName: "square.grid.2x2")
                            }
                        }

                Image(systemName: "plus.circle")
                    .resizable()
                    .frame(width: 40, height: 40)
                    .shadow(color: .gray, radius: 2, x: 0, y: 5)
                    .offset(x: geometry.size.width / 2 - 20, y: geometry.size.height - 80)
                    .onTapGesture {
                        self.showActionSheet.toggle()
                }
            }

        }
        .actionSheet(isPresented: $showActionSheet) {
            ActionSheet(title: Text("some actions"))
        }

    }
}

因此某些图像将覆盖中心的tabView项，该项将不可见（Text(" ")）：

更新

如果您仍然需要在这3个视图之间切换，则可以使用@State var selection（不要忘记使用tag(...) tabItems）：

struct TabViewModel: View {

    @State var selection: Int = 0
    var body: some View {

        ZStack {
            GeometryReader { geometry in
                TabView(selection: self.$selection) {
    //...
                    Text("plus")
                        .tabItem {
                            Text(" ")
                    }.tag(1)
    //...
                .onTapGesture {
                        self.selection = 1
                }
    // ...
}

Answer 2

SWIFTUI 2

//VARIABLES string gLetter = null, studentName = null; int test1 = 0, test2 = 0, test3 = 0, avg = 0; private void processButton_Click(object sender, EventArgs e) { try { getdata(); calculatedata(); displaydata(); resetitems(); } catch { MessageBox.Show("Error"); } } private void getdata() { try { StreamReader inputFile; if (openFile.ShowDialog() == DialogResult.OK) { inputFile = File.OpenText(openFile.FileName); while (!inputFile.EndOfStream) { studentName = inputFile.ReadLine(); test1 = int.Parse(inputFile.ReadLine()); test2 = int.Parse(inputFile.ReadLine()); test3 = int.Parse(inputFile.ReadLine()); } } } catch (Exception) { MessageBox.Show("Error"); } } private void calculatedata() { try { //calc avg avg = (test1 + test2 + test3) / 3; //find gLetter if (avg >= 90) gLetter = "A"; else if (avg >= 80) gLetter = "B"; else if (avg >= 70) gLetter = "C"; else if (avg >= 60) gLetter = "D"; else if (avg < 60) gLetter = "F"; } catch { MessageBox.Show("Error"); } } private void displaydata() { try { listBox1.Items.Add(studentName + "\t" + avg.ToString("N2") + "\t" + gLetter); } catch (Exception) { MessageBox.Show("Error"); } } private void resetitems() { openFile.FileName = " "; } private void exitButton_Click(object sender, EventArgs e) { try { Application.Exit(); } catch { MessageBox.Show("Error"); } } 的使用有时会导致意外行为，例如不显示覆盖视图（警报、工作表或全屏）或在您单击另一个选项卡时显示它。更安全的方法是使用 .onTapGesture 方法设置选择值：

.onChange(of:)

}

TabView tabItem图像移到顶部

2 个答案: