HarmonyOS API：通用事件

// xxx.ets
@Entry
@Component
struct KeyEventExample {
  @State text: string = ''
  @State eventType: string = ''

  build() {
    Column() {
      Button('KeyEvent')
        .onKeyEvent((event: KeyEvent) => {
          if (event.type === KeyType.Down) {
            this.eventType = 'Down'
          }
          if (event.type === KeyType.Up) {
            this.eventType = 'Up'
          }
          this.text = 'KeyType:' + this.eventType + '\nkeyCode:' + event.keyCode + '\nkeyText:' + event.keyText
        })
      Text(this.text).padding(15)
    }.height(300).width('100%').padding(35)
  }
}

// xxx.ets
@Entry
@Component
struct FocusEventExample {
  @State oneButtonColor: string = '#FFC0CB'
  @State twoButtonColor: string = '#87CEFA'
  @State threeButtonColor: string = '#90EE90'

  build() {
    Column({ space: 20 }) {
      // 通过外接键盘的上下键可以让焦点在三个按钮间移动，按钮获焦时颜色变化，失焦时变回原背景色
      Button('First Button')
        .backgroundColor(this.oneButtonColor)
        .width(260)
        .height(70)
        .fontColor(Color.Black)
        .focusable(true)
        .onFocus(() => {
          this.oneButtonColor = '#FF0000'
        })
        .onBlur(() => {
          this.oneButtonColor = '#FFC0CB'
        })
      Button('Second Button')
        .backgroundColor(this.twoButtonColor)
        .width(260)
        .height(70)
        .fontColor(Color.Black)
        .focusable(true)
        .onFocus(() => {
          this.twoButtonColor = '#FF0000'
        })
        .onBlur(() => {
          this.twoButtonColor = '#87CEFA'
        })
      Button('Third Button')
        .backgroundColor(this.threeButtonColor)
        .width(260)
        .height(70)
        .fontColor(Color.Black)
        .focusable(true)
        .onFocus(() => {
          this.threeButtonColor = '#FF0000'
        })
        .onBlur(() => {
          this.threeButtonColor = '#90EE90'
        })
    }.width('100%').margin({ top: 20 })
  }
}

// xxx.ets
@Entry
@Component
struct MouseEventExample {
  @State hoverText: string = 'no hover';
  @State mouseText: string = '';
  @State action: string = '';
  @State mouseBtn: string = '';
  @State color: Color = Color.Blue;

  build() {
    Column({ space: 20 }) {
      Button(this.hoverText)
        .width(180).height(80)
        .backgroundColor(this.color)
        .onHover((isHover: boolean) => {
          // 通过onHover事件动态修改按钮在是否有鼠标悬浮时的文本内容与背景颜色
          if (isHover) {
            this.hoverText = 'hover';
            this.color = Color.Pink;
          } else {
            this.hoverText = 'no hover';
            this.color = Color.Blue;
          }
        })
      Button('onMouse')
        .width(180).height(80)
        .onMouse((event: MouseEvent) => {
          switch (event.button) {
            case MouseButton.None:
              this.mouseBtn = 'None';
              break;
            case MouseButton.Left:
              this.mouseBtn = 'Left';
              break;
            case MouseButton.Right:
              this.mouseBtn = 'Right';
              break;
            case MouseButton.Back:
              this.mouseBtn = 'Back';
              break;
            case MouseButton.Forward:
              this.mouseBtn = 'Forward';
              break;
            case MouseButton.Middle:
              this.mouseBtn = 'Middle';
              break;
          }
          switch (event.action) {
            case MouseAction.Hover:
              this.action = 'Hover';
              break;
            case MouseAction.Press:
              this.action = 'Press';
              break;
            case MouseAction.Move:
              this.action = 'Move';
              break;
            case MouseAction.Release:
              this.action = 'Release';
              break;
          }
          this.mouseText = 'onMouse:\nButton = ' + this.mouseBtn +
          '\nAction = ' + this.action + '\nXY=(' + event.x + ',' + event.y + ')' +
          '\nscreenXY=(' + event.screenX + ',' + event.screenY + ')';
        })
      Text(this.mouseText)
    }.padding({ top: 30 }).width('100%')
  }
}

// xxx.ets
@Entry
@Component
struct AreaExample {
  @State value: string = 'Text'
  @State sizeValue: string = ''

  build() {
    Column() {
      Text(this.value)
        .backgroundColor(Color.Green).margin(30).fontSize(20)
        .onClick(() => {
          this.value = this.value + 'Text'
        })
        .onAreaChange((oldValue: Area, newValue: Area) => {
          console.info(`Ace: on area change, oldValue is ${JSON.stringify(oldValue)} value is ${JSON.stringify(newValue)}`)
          this.sizeValue = JSON.stringify(newValue)
        })
      Text('new area is: \n' + this.sizeValue).margin({ right: 30, left: 30 })
    }
    .width('100%').height('100%').margin({ top: 30 })
  }
}

// xxx.ets
@Entry
@Component
struct ScrollExample {
  scroller: Scroller = new Scroller()
  private arr: number[] = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
  @State testTextStr: string = 'test'
  @State testRowStr: string = 'test'

  build() {
    Column() {
      Column() {
        Text(this.testTextStr)
          .fontSize(20)

        Text(this.testRowStr)
          .fontSize(20)
      }
      .height(100)
      .backgroundColor(Color.Gray)
      .opacity(0.3)

      Scroll(this.scroller) {
        Column() {
          Text("Test Text Visible Change")
            .fontSize(20)
            .height(200)
            .margin({ top: 50, bottom: 20 })
            .backgroundColor(Color.Green)
              // 通过设置ratios为[0.0, 1.0]，实现当组件完全显示或完全消失在屏幕中时触发回调
            .onVisibleAreaChange([0.0, 1.0], (isVisible: boolean, currentRatio: number) => {
              console.info('Test Text isVisible: ' + isVisible + ', currentRatio:' + currentRatio)
              if (isVisible && currentRatio >= 1.0) {
                console.info('Test Text is fully visible. currentRatio:' + currentRatio)
                this.testTextStr = 'Test Text is fully visible'
              }

              if (!isVisible && currentRatio <= 0.0) {
                console.info('Test Text is completely invisible.')
                this.testTextStr = 'Test Text is completely invisible'
              }
            })

          Row() {
            Text('Test Row Visible  Change')
              .fontSize(20)
              .margin({ bottom: 20 })

          }
          .height(200)
          .backgroundColor(Color.Yellow)
          .onVisibleAreaChange([0.0, 1.0], (isVisible: boolean, currentRatio: number) => {
            console.info('Test Row isVisible:' + isVisible + ', currentRatio:' + currentRatio)
            if (isVisible && currentRatio >= 1.0) {
              console.info('Test Row is fully visible.')
              this.testRowStr = 'Test Row is fully visible'
            }

            if (!isVisible && currentRatio <= 0.0) {
              console.info('Test Row is is completely invisible.')
              this.testRowStr = 'Test Row is is completely invisible'
            }
          })

          ForEach(this.arr, (item) => {
            Text(item.toString())
              .width('90%')
              .height(150)
              .backgroundColor(0xFFFFFF)
              .borderRadius(15)
              .fontSize(16)
              .textAlign(TextAlign.Center)
              .margin({ top: 10 })
          }, item => item)

        }.width('100%')
      }
      .backgroundColor(0x317aff)
      .scrollable(ScrollDirection.Vertical)
      .scrollBar(BarState.On)
      .scrollBarColor(Color.Gray)
      .scrollBarWidth(30)
      .onScroll((xOffset: number, yOffset: number) => {
        console.info(xOffset + ' ' + yOffset)
      })
      .onScrollEdge((side: Edge) => {
        console.info('To the edge')
      })
      .onScrollEnd(() => {
        console.info('Scroll Stop')
      })

    }.width('100%').height('100%').backgroundColor(0xDCDCDC)
  }
}