SwiftUI键盘ToolbarItem点击后消失的真机适配问题求助

问题根源 #

iOS16.3版本的SwiftUI键盘Toolbar存在视图刷新逻辑bug，当通过ToolbarItem触发输入框焦点切换时，系统会错误地销毁并重建键盘Toolbar，导致按钮丢失；而iOS16.2模拟器的Toolbar渲染逻辑尚未引入该问题，因此表现正常。

具体修复方案 #

1. 用ToolbarItemGroup包裹ToolbarItem（优先推荐） #

将单独的ToolbarItem放入ToolbarItemGroup(placement: .keyboard)中，强化系统对键盘Toolbar结构的识别，避免意外销毁：

struct ContentView: View {
    @FocusState private var focusedField: Field?
    
    enum Field {
        case username, password
    }
    
    var body: some View {
        Form {
            TextField("用户名", text: .constant(""))
                .focused($focusedField, equals: .username)
            SecureField("密码", text: .constant(""))
                .focused($focusedField, equals: .password)
        }
        .toolbar {
            ToolbarItemGroup(placement: .keyboard) {
                Spacer()
                Button("下一项") {
                    focusedField = focusedField == .username ? .password : nil
                }
            }
        }
    }
}

2. 优化焦点切换的执行逻辑 #

如果必须单独使用ToolbarItem，可在焦点切换操作外包裹withAnimation，或加入微延迟，减少视图刷新冲突：

Button("下一项") {
    withAnimation {
        focusedField = focusedField == .username ? .password : nil
    }
}

3. 改用UIKit兼容层（终极稳定方案） #

若上述SwiftUI原生方案无效，可通过UIKit的inputAccessoryView实现键盘工具栏，彻底规避SwiftUI的版本bug：

struct TextFieldWithToolbar: UIViewRepresentable {
    var placeholder: String
    @Binding var text: String
    var nextAction: () -> Void
    
    func makeUIView(context: Context) -> UITextField {
        let textField = UITextField()
        textField.placeholder = placeholder
        
        // 构建键盘工具栏
        let toolbar = UIToolbar()
        toolbar.sizeToFit()
        let nextButton = UIBarButtonItem(title: "下一项", style: .plain, target: context.coordinator, action: #selector(Coordinator.nextTapped))
        toolbar.items = [UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil), nextButton]
        textField.inputAccessoryView = toolbar
        
        return textField
    }
    
    func updateUIView(_ uiView: UITextField, context: Context) {
        uiView.text = text
    }
    
    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }
    
    class Coordinator: NSObject {
        var parent: TextFieldWithToolbar
        
        init(_ parent: TextFieldWithToolbar) {
            self.parent = parent
        }
        
        @objc func nextTapped() {
            parent.nextAction()
        }
    }
}

// 使用示例
struct ContentView: View {
    @FocusState private var focusedField: Field?
    @State private var username = ""
    @State private var password = ""
    
    enum Field {
        case username, password
    }
    
    var body: some View {
        Form {
            TextFieldWithToolbar(placeholder: "用户名", text: $username) {
                focusedField = .password
            }
            .focused($focusedField, equals: .username)
            
            SecureField("密码", text: $password)
                .focused($focusedField, equals: .password)
        }
    }
}

额外注意事项 #

• 确保@FocusState变量与输入框的绑定逻辑正确，避免状态混乱引发Toolbar异常
• 尽量简化ToolbarItem的action逻辑，避免在其中执行复杂的视图更新操作

内容的提问来源于stack exchange，提问作者DeveloperSammy