如何实现软键盘弹出后，整体布局不变

// xxx.ets 
@Entry 
@Component 
struct TextInputExample { 
  scroller: Scroller = new Scroller(); 
  @State Text: string = ''; 
 
  build() { 
    Scroll(this.scroller) { 
      Column({ space: 20 }) { 
        TextInput({ placeholder: 'Please enter the content.' }) 
          .expandSafeArea([SafeAreaType.KEYBOARD]) 
          .type(InputType.Password) 
          .margin({ top: 200 }) 
        TextInput({ placeholder: 'Please enter the content.' }) 
          .expandSafeArea([SafeAreaType.KEYBOARD]) 
          .margin({ top: 200 }) 
        Text(`UserName：${this.Text}`) 
          .expandSafeArea([SafeAreaType.KEYBOARD]) 
          .width('80%') 
          .margin({ top: 200 }) 
        TextInput({ placeholder: 'Please enter a user name.', text: this.Text }) 
          .expandSafeArea([SafeAreaType.KEYBOARD]) 
          .margin({ top: 200 }) 
          .onChange((value: string) => { 
            this.Text = value; 
          }) 
      } 
      .width('100%') 
    } 
    .scrollBar(BarState.Off) 
  } 
}