HarmonyOS 实现底部导航栏

该功能实现需要Tabs、TabsController、TabContent、Column等组件

Tabs相当于Android中的BottomNavigationView
TabContent相当于Android中的fragment
TabBuilder内相当于每个Item

@Entry
@Component
struct Main {

  public tabsController : object = new TabsController()
  @State currentIndex:number = 0

  build() {
    Tabs({barPosition:BarPosition.End,controller:this.tabsController}) {
      TabContent() {
        Text('首页的内容').fontSize(30)
      }
      .tabBar(this.TabBuilder("首页",0,$r('app.media.icon_main_tab_home_true'),$r('app.media.icon_main_tab_home_false')))
      TabContent() {
        Text('公众号的内容').fontSize(30)
      }
      .tabBar(this.TabBuilder("公众号",1,$r('app.media.icon_main_tab_public_true'),$r('app.media.icon_main_tab_public_false')))
      TabContent() {
        Text('体系的内容').fontSize(30)
      }
      .tabBar(this.TabBuilder("体系",2,$r('app.media.icon_main_tab_system_true'),$r('app.media.icon_main_tab_system_false')))
      TabContent() {
        Text('项目的内容').fontSize(30)
      }
      .tabBar(this.TabBuilder("项目",3,$r('app.media.icon_main_tab_project_true'),$r('app.media.icon_main_tab_project_false')))
    }.barHeight(100)
    .onChange((index:number) => {
      this.currentIndex = index
    })
  }

  @Builder TabBuilder(title: string, targetIndex: number,selectedImg: Resource,normalImg: Resource) {
    Column() {
      Image(this.currentIndex === targetIndex ? selectedImg : normalImg)
        .size({ width: 30, height: 30 })
      Text(title)
        .fontColor(this.currentIndex === targetIndex ? '#5DA0FF' : '#999999')
    }
    .onClick(() => {
      this.currentIndex = targetIndex;
      this.tabsController.changeIndex(this.currentIndex);
    })
    .justifyContent(FlexAlign.Center)
  }
}