ArkUI為組件提供了通用的屬性動畫和轉場動畫能力的同時，還為一些組件提供了默認的動畫效果。例如，List的滑動動效，Button的點擊動效，是組件自帶的默認動畫效果。在組件默認動畫效果的基礎上，開發(fā)者還可以通過屬性動畫和轉場動畫對容器組件內的子組件動效進行定制。

使用組件默認動畫

組件默認動效具備以下功能：

• 提示用戶當前狀態(tài)，例如用戶點擊Button組件時，Button組件默認變灰，用戶即確定完成選中操作。
• 提升界面精致程度和生動性。
• 減少開發(fā)者工作量，例如列表滑動組件自帶滑動動效，開發(fā)者直接調用即可。

更多效果，可以參考組件說明。

示例代碼和效果如下。

@Entry
@Component
struct ComponentDemo {
  build() {
    Row() {
      Checkbox({ name: 'checkbox1', group: 'checkboxGroup' })
        .select(true)
        .shape(CheckBoxShape.CIRCLE)
        .size({ width: 50, height: 50 })
    }
    .width('100%')
    .height('100%')
    .justifyContent(FlexAlign.Center)
  }
}
ts

打造組件定制化動效

部分組件支持通過屬性動畫和轉場動畫自定義組件子Item的動效，實現定制化動畫效果。例如，Scroll組件中可對各個子組件在滑動時的動畫效果進行定制。

• 在滑動或者點擊操作時通過改變各個Scroll子組件的仿射屬性來實現各種效果。
• 如果要在滑動過程中定制動效，可在滑動回調onScroll中監(jiān)控滑動距離，并計算每個組件的仿射屬性。也可以自己定義手勢，通過手勢監(jiān)控位置，手動調用ScrollTo改變滑動位置。
• 在滑動回調onScrollStop或手勢結束回調中對滑動的最終位置進行微調。

定制Scroll組件滑動動效示例代碼和效果如下。

import curves from '@ohos.curves';
import window from '@ohos.window';
import display from '@ohos.display';
import mediaquery from '@ohos.mediaquery';
import UIAbility from '@ohos.app.ability.UIAbility';

export default class GlobalContext extends AppStorage{
  static mainWin: window.Window|undefined = undefined;
  static mainWindowSize:window.Size|undefined = undefined;
}
/**
 * 窗口、屏幕相關信息管理類
 */
export class WindowManager {
  private static instance: WindowManager|null = null;
  private displayInfo: display.Display|null = null;
  private orientationListener = mediaquery.matchMediaSync('(orientation: landscape)');

  constructor() {
    this.orientationListener.on('change', (mediaQueryResult: mediaquery.MediaQueryResult) = > { this.onPortrait(mediaQueryResult) })
    this.loadDisplayInfo()
  }

  /**
   * 設置主window窗口
   * @param win 當前app窗口
   */
  setMainWin(win: window.Window) {
    if (win == null) {
      return
    }
    GlobalContext.mainWin = win;
    win.on("windowSizeChange", (data: window.Size) = > {
      if (GlobalContext.mainWindowSize == undefined || GlobalContext.mainWindowSize == null) {
        GlobalContext.mainWindowSize = data;
      } else {
        if (GlobalContext.mainWindowSize.width == data.width && GlobalContext.mainWindowSize.height == data.height) {
          return
        }
        GlobalContext.mainWindowSize = data;
      }

      let winWidth = this.getMainWindowWidth();
      AppStorage.setOrCreate< number >('mainWinWidth', winWidth)
      let winHeight = this.getMainWindowHeight();
      AppStorage.setOrCreate< number >('mainWinHeight', winHeight)
      let context:UIAbility = new UIAbility()
      context.context.eventHub.emit("windowSizeChange", winWidth, winHeight)
    })
  }

  static getInstance(): WindowManager {
    if (WindowManager.instance == null) {
      WindowManager.instance = new WindowManager();
    }
    return WindowManager.instance
  }

  private onPortrait(mediaQueryResult: mediaquery.MediaQueryResult) {
    if (mediaQueryResult.matches == AppStorage.get< boolean >('isLandscape')) {
      return
    }
    AppStorage.setOrCreate< boolean >('isLandscape', mediaQueryResult.matches)
    this.loadDisplayInfo()
  }

  /**
   * 切換屏幕方向
   * @param ori 常量枚舉值：window.Orientation
   */
  changeOrientation(ori: window.Orientation) {
    if (GlobalContext.mainWin != null) {
      GlobalContext.mainWin.setPreferredOrientation(ori)
    }
  }

  private loadDisplayInfo() {
    this.displayInfo = display.getDefaultDisplaySync()
    AppStorage.setOrCreate< number >('displayWidth', this.getDisplayWidth())
    AppStorage.setOrCreate< number >('displayHeight', this.getDisplayHeight())
  }

  /**
   * 獲取main窗口寬度，單位vp
   */
  getMainWindowWidth(): number {
    return GlobalContext.mainWindowSize != null ? px2vp(GlobalContext.mainWindowSize.width) : 0
  }

  /**
   * 獲取main窗口高度，單位vp
   */
  getMainWindowHeight(): number {
    return GlobalContext.mainWindowSize != null ? px2vp(GlobalContext.mainWindowSize.height) : 0
  }

  /**
   * 獲取屏幕寬度，單位vp
   */
  getDisplayWidth(): number {
    return this.displayInfo != null ? px2vp(this.displayInfo.width) : 0
  }

  /**
   * 獲取屏幕高度，單位vp
   */
  getDisplayHeight(): number {
    return this.displayInfo != null ? px2vp(this.displayInfo.height) : 0
  }

  /**
   * 釋放資源
   */
  release() {
    if (this.orientationListener) {
      this.orientationListener.off('change', (mediaQueryResult: mediaquery.MediaQueryResult) = > { this.onPortrait(mediaQueryResult)})
    }
    if (GlobalContext.mainWin != null) {
      GlobalContext.mainWin.off('windowSizeChange')
    }
    WindowManager.instance = null;
  }
}

/**
 * 封裝任務卡片信息數據類
 */
export class TaskData {
  bgColor: Color | string | Resource = Color.White;
  index: number = 0;
  taskInfo: string = 'music';

  constructor(bgColor: Color | string | Resource, index: number, taskInfo: string) {
    this.bgColor = bgColor;
    this.index = index;
    this.taskInfo = taskInfo;
  }
}

export const taskDataArr: Array< TaskData > =
  [
    new TaskData('#317AF7', 0, 'music'),
    new TaskData('#D94838', 1, 'mall'),
    new TaskData('#DB6B42 ', 2, 'photos'),
    new TaskData('#5BA854', 3, 'setting'),
    new TaskData('#317AF7', 4, 'call'),
    new TaskData('#D94838', 5, 'music'),
    new TaskData('#DB6B42', 6, 'mall'),
    new TaskData('#5BA854', 7, 'photos'),
    new TaskData('#D94838', 8, 'setting'),
    new TaskData('#DB6B42', 9, 'call'),
    new TaskData('#5BA854', 10, 'music')

  ];

@Entry
@Component
export struct TaskSwitchMainPage {
  displayWidth: number = WindowManager.getInstance().getDisplayWidth();
  scroller: Scroller = new Scroller();
  cardSpace: number = 0; // 卡片間距
  cardWidth: number = this.displayWidth / 2 - this.cardSpace / 2; // 卡片寬度
  cardHeight: number = 400; // 卡片高度
  cardPosition: Array< number > = []; // 卡片初始位置
  clickIndex: boolean = false;
  @State taskViewOffsetX: number = 0;
  @State cardOffset: number = this.displayWidth / 4;
  lastCardOffset: number = this.cardOffset;
  startTime: number|undefined=undefined

  // 每個卡片初始位置
  aboutToAppear() {
    for (let i = 0; i < taskDataArr.length; i++) {
      this.cardPosition[i] = i * (this.cardWidth + this.cardSpace);
    }
  }

  // 每個卡片位置
  getProgress(index: number): number {
    let progress = (this.cardOffset + this.cardPosition[index] - this.taskViewOffsetX + this.cardWidth / 2) / this.displayWidth;
    return progress
  }

  build() {
    Stack({ alignContent: Alignment.Bottom }) {
      // 背景
      Column()
        .width('100%')
        .height('100%')
        .backgroundColor(0xF0F0F0)

      // 滑動組件
      Scroll(this.scroller) {
        Row({ space: this.cardSpace }) {
          ForEach(taskDataArr, (item:TaskData, index) = > {
            Column()
              .width(this.cardWidth)
              .height(this.cardHeight)
              .backgroundColor(item.bgColor)
              .borderStyle(BorderStyle.Solid)
              .borderWidth(1)
              .borderColor(0xAFEEEE)
              .borderRadius(15)
                // 計算子組件的仿射屬性
              .scale((this.getProgress(index) >= 0.4 && this.getProgress(index) <= 0.6) ?
                {
                  x: 1.1 - Math.abs(0.5 - this.getProgress(index)),
                  y: 1.1 - Math.abs(0.5 - this.getProgress(index))
                } :
                { x: 1, y: 1 })
              .animation({ curve: Curve.Smooth })
                // 滑動動畫
              .translate({ x: this.cardOffset })
              .animation({ curve: curves.springMotion() })
              .zIndex((this.getProgress(index) >= 0.4 && this.getProgress(index) <= 0.6) ? 2 : 1)
          }, (item:TaskData) = > item.toString())
        }
        .width((this.cardWidth + this.cardSpace) * (taskDataArr.length + 1))
        .height('100%')
      }
      .gesture(
        GestureGroup(GestureMode.Parallel,
          PanGesture({ direction: PanDirection.Horizontal, distance: 5 })
            .onActionStart((event: GestureEvent|undefined) = > {
              if(event){
                this.startTime = event.timestamp;
              }
            })
            .onActionUpdate((event: GestureEvent|undefined) = > {
              if(event){
                this.cardOffset = this.lastCardOffset + event.offsetX;
              }
            })
            .onActionEnd((event: GestureEvent|undefined) = > {
              if(event){
                let time = 0
                if(this.startTime){
                  time = event.timestamp - this.startTime;
                }
                let speed = event.offsetX / (time / 1000000000);
                let moveX = Math.pow(speed, 2) / 7000 * (speed > 0 ? 1 : -1);

                this.cardOffset += moveX;
                // 左滑大于最右側位置
                let cardOffsetMax = -(taskDataArr.length - 1) * (this.displayWidth / 2);
                if (this.cardOffset < cardOffsetMax) {
                  this.cardOffset = cardOffsetMax;
                }
                // 右滑大于最左側位置
                if (this.cardOffset > this.displayWidth / 4) {
                  this.cardOffset = this.displayWidth / 4;
                }

                // 左右滑動距離不滿足/滿足切換關系時，補位/退回
                let remainMargin = this.cardOffset % (this.displayWidth / 2);
                if (remainMargin < 0) {
                  remainMargin = this.cardOffset % (this.displayWidth / 2) + this.displayWidth / 2;
                }
                if (remainMargin <= this.displayWidth / 4) {
                  this.cardOffset += this.displayWidth / 4 - remainMargin;
                } else {
                  this.cardOffset -= this.displayWidth / 4 - (this.displayWidth / 2 - remainMargin);
                }

                // 記錄本次滑動偏移量
                this.lastCardOffset = this.cardOffset;
              }
            })
        ), GestureMask.IgnoreInternal)
      .scrollable(ScrollDirection.Horizontal)
      .scrollBar(BarState.Off)

      // 滑動到首尾位置
      Button('Move to first/last')
        .backgroundColor(0x888888)
        .margin({ bottom: 30 })
        .onClick(() = > {
          this.clickIndex = !this.clickIndex;

          if (this.clickIndex) {
            this.cardOffset = this.displayWidth / 4;
          } else {
            this.cardOffset = this.displayWidth / 4 - (taskDataArr.length - 1) * this.displayWidth / 2;
          }
          this.lastCardOffset = this.cardOffset;
        })
    }
    .width('100%')
    .height('100%')
  }
}
ts

審核編輯 黃宇