空文本字段时，SwiftUI文本字段的字体大小会缩小

Question

我有两个仅接受数字的文本字段。每当文本在一个字段中更改时，也会同时更新另一个字段。如果清除编辑文本字段，占位符的字体大小将缩小。使用observedObject来跟踪文本的更改和在另一个文本字段中的更新。

VStack{
                HStack{
                    VStack{
                        Text("FROM")
                            .kerning(5.0)
                            .foregroundColor(Color.white.opacity(0.6))
                            .font(Font.system(size: self.hSize == .compact ? 24 : 48))
                            .bold()
                        TextField("amount", text: self.$textBindingManagerFROM.text
                            , onEditingChanged: {(val) in
                                self.textBindingManagerFROM.editing = true
                                self.textBindingManagerTO.editing = false
                        })
                            .keyboardType(.decimalPad)
                            .multilineTextAlignment(.center)
                            .allowsTightening(true)
                            .lineLimit(1)
                            .minimumScaleFactor(0.3)
                            .font(Font.system(size: self.hSize == .compact ? 24 : 48))
                            .frame(minHeight: self.hSize == .compact ? 50 : 100, alignment: .leading)
                    }
                    VStack{
                        Text("TO")
                            .foregroundColor(Color.white.opacity(0.5))
                            .font(Font.system(size: self.hSize == .compact ? 24 : 48))
                            .bold()
                            .kerning(5.0)
                        TextField("amount", text: self.$textBindingManagerTO.text, onEditingChanged: {(val) in
                                self.textBindingManagerFROM.editing = false
                                self.textBindingManagerTO.editing = true
                            })
                            .keyboardType(.numberPad)
                            .multilineTextAlignment(.center)
                            .allowsTightening(true)
                            .lineLimit(1)
                            .minimumScaleFactor(0.3)
                            .font(Font.system(size: self.hSize == .compact ? 24 : 48))
                    }
                    
                }
                .padding(.horizontal, 16)
            }

@ObservedObject var textBindingManagerFROM = TextBindingManager(limit: 12, _editing: false)
    @ObservedObject var textBindingManagerTO = TextBindingManager(limit: 16, _editing: false)