什么网站可以教做面包,东阳实惠营销型网站建设,婚恋网网站架构,网站的当前位置导航如何做1、HarmonyOS 只调用根节点的dispose,是否其下的子节点都能析构掉还是需要遍历子节点#xff0c;都执行dispose才能正常析构#xff1f;
前端持有引用关系的需要dispose#xff0c;new出来的builderNode和FrameNode也需要dispose。只调用根节点的dispose,无法保证其下的子节…1、HarmonyOS 只调用根节点的dispose,是否其下的子节点都能析构掉还是需要遍历子节点都执行dispose才能正常析构
前端持有引用关系的需要disposenew出来的builderNode和FrameNode也需要dispose。只调用根节点的dispose,无法保证其下的子节点能够正常释放
2、HarmonyOS 如何在Web UserAgent中区分手机设备与pad设备
参考https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/multi-faq-V5#ZH-CN_TOPIC_0000001884757262__%E5%A6%82%E4%BD%95%E6%9F%A5%E8%AF%A2%E8%AE%BE%E5%A4%87%E7%B1%BB%E5%9E%8B
通过命令行的方式查询设备类型。 通过命令行查询指定系统参数const.product.devicetype进而确定设备类型 # 方法一hdc shell param get const.product.devicetype# 方法二hdc shell cat /etc/param/ohos.para | grep const.product.devicetype在应用开发过程中查询设备类型。 import { deviceInfo } fromkit.BasicServicesKitEntryComponentstruct GetDeviceTypeSample {State deviceType:stringunknownaboutToAppear() {this.deviceType deviceInfo.deviceType}build() {Column() {Text(this.deviceType).fontSize(24)}.width(100%).height(100%)}
}3、HarmonyOS Navigation路由问题
在Index页面跳转PageOne页面的同时隐藏了导航页hideNavBar但是在PageOne页面返回上一页时为什么会出现白屏的情况
// Index.ets
Entry
Component
struct Index {State hideNavBar: boolean falseprivate pageStack: NavPathStack new NavPathStack()build() {Navigation(this.pageStack) {Column() {Button(跳转PageOne,隐藏NavBar).onClick(() {this.hideNavBar truethis.pageStack.replacePath({name: PageOne})})}.height(100%).justifyContent(FlexAlign.Center)}.hideNavBar(this.hideNavBar).hideTitleBar(true).hideBackButton(true)}
}// PageOne.ets
Builder
function PageOneBuilder() {PageOne()
}Component
export struct PageOne {pageStack: NavPathStack | null nullbuild() {NavDestination() {Column() {Button(返回上一页).onClick(() {// 这里返回上一页this.pageStack?.pop?.()})}.height(100%)}.hideTitleBar(true).onReady((ctx: NavDestinationContext) {this.pageStack ctx.pathStack})}
}api介绍https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/arkts-navigation-navigation-V5
白屏的情况是隐藏了导航页Navigation导致 hideNavBar(true)设置为false回去就能看到上一个界面的导航页按钮。可以在Navigation上加一个button组件在返回即使隐藏了Navigation也能看到button组件。具体使用再参考下api文档。
4、HarmonyOS Tabs组件宽度问题
文档显示Tabs组件的指示器和视图的宽度一样app首页的会有很多栏目在栏目的右边会有一个半透明的遮盖条和一个按钮在这里有办法分开写吗或者有其他的组件可以替代这个会影响操作最后的一两个栏目可能会点不到。
参考以下demo:
Entry
Component
struct tabTest {State tabArray: Arraynumber [0, 1, 2, 3,4]State focusIndex: number 0State pre: number 0State index: number 0private controller: TabsController new TabsController()State test: boolean falseState animationDuration: number 300State indicatorLeftMargin: number 0State indicatorWidth: number 0private tabsWidth: number 0private tabWidth: number 0;private scrollerForScroll: Scroller new Scroller()// 单独的页签BuilderTab(tabName: string, tabItem: number, tabIndex: number) {Row({ space: 20 }) {Text(tabName).fontSize(18).fontColor(tabIndex this.focusIndex ? Color.Blue :Color.Black).id(tabIndex.toString()).onAreaChange((oldValue: Area,newValue: Area) {if (this.focusIndex tabIndex (this.indicatorLeftMargin 0 || this.indicatorWidth 0)){if (newValue.position.x ! undefined) {let positionX Number.parseFloat(newValue.position.x.toString())this.indicatorLeftMargin Number.isNaN(positionX) ? 0 : positionX}let width Number.parseFloat(newValue.width.toString())this.tabWidth Number.isNaN(width) ? 0 : widththis.indicatorWidth this.tabWidth}})}.justifyContent(FlexAlign.Center).constraintSize({ minWidth: 35 }).width(100).height(30).onClick(() {this.controller.changeIndex(tabIndex)this.focusIndex tabIndex}).backgroundColor(#ffb7b7b7)}BuildertextTest(textName:string){Row({ space: 20 }) {Text(textName).fontSize(18)}.justifyContent(FlexAlign.Center).constraintSize({ minWidth: 35 }).height(30).backgroundColor(#ffb7b7b7)}build() {Column() {Stack({ alignContent: Alignment.TopStart }) {Column() {// 页签Row({ space: 8 }) {List({ space: 20, initialIndex: 0, scroller: this.scrollerForScroll }) {ForEach(this.tabArray, (item: number, index: number) {ListItem() {this.Tab(页签 item, item, index)}}, (item: string) item)}.listDirection(Axis.Horizontal).height(30).width(80%).friction(0.6).alignListItem(ListItemAlign.Start).scrollBar(BarState.Off).width(80%).backgroundColor(#ffb7b7b7).onScroll((xOffset: number, yOffset: number) {this.indicatorLeftMargin - xOffset})this.textTest(更多)}.alignItems(VerticalAlign.Bottom).width(100%).backgroundColor(#ffb7b7b7)}.alignItems(HorizontalAlign.Start).width(100%)Column().height(2).width(this.indicatorWidth).margin({ left: this.indicatorLeftMargin, top:30}).backgroundColor(Color.Blue)Column().height(10).width(20%).margin({ left: 80%, top:28}).backgroundColor(#ffb7b7b7)}.height(40).width(100%).backgroundColor(#ffb7b7b7)//tabsTabs({ barPosition: BarPosition.Start, controller: this.controller }) {ForEach(this.tabArray, (item: number, index: number) {TabContent() {Text(我是页面 item 的内容).height(300).width(100%).fontSize(30)}.backgroundColor(Color.White)}, (item: string) item)}.onAreaChange((oldValue: Area,newValue: Area) {let width Number.parseFloat(newValue.width.toString())this.tabsWidth Number.isNaN(width) ? 0 : width}).width(100%).barHeight(0).animationDuration(100).onChange((index: number) {console.log(foo change)this.focusIndex indexthis.scrollerForScroll.scrollToIndex(index-1,true)}).onAnimationStart((index: number, targetIndex: number, event: TabsAnimationEvent) {// 切换动画开始时触发该回调。下划线跟着页面一起滑动this.focusIndex targetIndexlet targetIndexInfo this.getTextInfo(targetIndex)this.startAnimateTo(this.animationDuration, targetIndexInfo.left, targetIndexInfo.width)}).onAnimationEnd((index: number,event: TabsAnimationEvent) {// 切换动画结束时触发该回调。下划线动画停止。let currentIndicatorInfo this.getCurrentIndicatorInfo(index,event)this.startAnimateTo(0,currentIndicatorInfo.left,currentIndicatorInfo.width)}).onGestureSwipe((index: number,event: TabsAnimationEvent) {// 在页面跟手滑动过程中逐帧触发该回调。let currentIndicatorInfo this.getCurrentIndicatorInfo(index,event)this.focusIndex currentIndicatorInfo.indexthis.indicatorLeftMargin currentIndicatorInfo.leftthis.tabWidth currentIndicatorInfo.widththis.indicatorWidth currentIndicatorInfo.width})}.height(100%)}private getTextInfo(index: number): Recordstring, number {let strJson getInspectorByKey(index.toString())try {let obj: Recordstring, string JSON.parse(strJson)let rectInfo: number[][] JSON.parse([ obj.$rect ])return { left: px2vp(rectInfo[0][0]), width: px2vp(rectInfo[1][0] - rectInfo[0][0]) }} catch (error) {return { left: 0, width: 0 }}}private getCurrentIndicatorInfo(index: number, event: TabsAnimationEvent): Recordstring, number {let nextIndex indexif (index 0 event.currentOffset 0) {nextIndex--} else if (index 4 event.currentOffset 0) {nextIndex}let indexInfo this.getTextInfo(index)let nextIndexInfo this.getTextInfo(nextIndex)let swipeRatio Math.abs(event.currentOffset / this.tabsWidth)let currentIndex swipeRatio 0.5 ? nextIndex : index // 页面滑动超过一半tabBar切换到下一页。let currentLeft indexInfo.left (nextIndexInfo.left - indexInfo.left) * swipeRatiolet currentWidth indexInfo.width (nextIndexInfo.width - indexInfo.width) * swipeRatioreturn { index: currentIndex, left: currentLeft, width: currentWidth }}private startAnimateTo(duration: number, leftMargin: number, width: number) {animateTo({duration: duration, // 动画时长curve: Curve.Linear, // 动画曲线iterations: 1, // 播放次数playMode: PlayMode.Normal, // 动画模式onFinish: () {console.info(play end)}}, () {this.indicatorLeftMargin leftMarginthis.tabWidth widththis.indicatorWidth width})}
}5、HarmonyOS 如何监听Map
可以用State来修饰Map变量现在支持Map、Set类型 但是不支持HashMap。
