悬浮窗拖拽和吸附动画

Stack({ alignContent: Alignment.Bottom }) {
  Video({
    src: $rawfile('float_window_video.mp4'),
    controller: this.videoController
  })
    .controls(false)
    .autoPlay(true)
    .loop(true)
    .muted(true)
    .width($r('app.string.float_window_full_size'))
    .onClick(() => {
      this.videoController.requestFullscreen(true);
    })
    .borderRadius($r('app.integer.float_window_content_border_radius'))
  Text($r('app.string.float_window_live_text'))
    .width($r('app.string.float_window_full_size'))
    .fontSize($r('app.string.ohos_id_text_size_body1'))
    .fontColor($r('app.color.ohos_id_color_background'))
    .textAlign(TextAlign.Center)
    .backgroundColor($r('app.color.ohos_id_color_list_alert'))
    .borderRadius({
      bottomLeft: $r('app.integer.float_window_content_border_radius'),
      bottomRight: $r('app.integer.float_window_content_border_radius')
    })
}
.clip(true)
.border({
  width: $r('app.integer.float_window_border_width'),
  color: $r('app.color.ohos_id_color_background')
})
.borderRadius($r('app.string.ohos_id_corner_radius_default_l'))
.width(Constants.FLOAT_WINDOW_WIDTH)
.height(Constants.FLOAT_WINDOW_HEIGHT)
.backgroundColor($r('app.color.ohos_id_color_foreground'))
.position({ x: this.positionX, y: this.positionY })
.onTouch((event: TouchEvent) => {
  this.onTouchEvent(event);
})

  try {
    const properties = windowClass.getWindowProperties();
    // 获取应用窗口宽高
    this.windowRectWidth = px2vp(properties.windowRect.width);
    this.windowRectHeight = px2vp(properties.windowRect.height)
    // 窗口宽度减去悬浮窗宽度和右边距让悬浮窗初始靠右
    this.positionX = this.windowRectWidth - Constants.FLOAT_WINDOW_WIDTH - Constants.PAGE_PADDING;
  } catch (exception) {
    logger.error(TAG, 'Failed to obtain the window properties. Cause: ' + JSON.stringify(exception));
  }

  try {
    const avoidArea = windowClass.getWindowAvoidArea(type);
    // 获取顶部状态栏高度
    this.topRectHeight = px2vp(avoidArea.topRect.height);
    // 获取底部导航栏高度
    this.bottomRectHeight = px2vp(avoidArea.bottomRect.height);
  } catch (exception) {
    logger.error(TAG, 'Failed to obtain the area. Cause:' + JSON.stringify(exception));
  }

  case TouchType.Down: {
    this.offsetX = event.touches[0].x;
    this.offsetY = event.touches[0].y;
    break;
  }

  case TouchType.Move: {
    const windowX: number = event.touches[0].windowX;
    const windowY: number = event.touches[0].windowY;
    // TODO：知识点：跟手动画，推荐使用默认参数的弹性跟手动画曲线curves.responsiveSpringMotion。
    animateTo({ curve: curves.responsiveSpringMotion() }, () => {
      this.positionX = windowX - this.offsetX - Constants.PAGE_PADDING;
      this.positionY = windowY - this.offsetY - this.topRectHeight - Constants.PAGE_PADDING; // 减去手指位置到悬浮窗左上角的y轴偏移和设备顶部状态栏高度
    })
    break;
  }

  case TouchType.Up: {
    // TODO：知识点：通过判断悬浮窗在窗口中的位置，设置悬浮窗贴边，使用curves.springMotion()弹性动画曲线，可以实现阻尼动画效果
    animateTo({ curve: curves.springMotion() }, () => {
      // 判断悬浮窗中心在水平方向是否超过窗口宽度的一半，根据结果设置靠左或靠右
      if (this.positionX > (this.windowRectWidth - Constants.FLOAT_WINDOW_WIDTH) / 2) {
        this.positionX = this.windowRectWidth - Constants.FLOAT_WINDOW_WIDTH - Constants.PAGE_PADDING; // 悬浮窗靠右
      } else {
        this.positionX = Constants.PAGE_PADDING; // 悬浮窗靠左
      }
      // 页面高度
      const pageHeight: number = this.windowRectHeight - this.topRectHeight - this.bottomRectHeight;
      // 判断悬浮窗是否超出内容区上下边界，根据结果将悬浮窗设置在边界位置
      if (this.positionY < Constants.PAGE_PADDING) {
        this.positionY = Constants.PAGE_PADDING;
      } else if (this.positionY > pageHeight - Constants.FLOAT_WINDOW_HEIGHT - Constants.PAGE_PADDING) {
        this.positionY = pageHeight - Constants.FLOAT_WINDOW_HEIGHT - Constants.PAGE_PADDING;
      }
    })
    break;
  }

floatwindow                                  // har类型
|---/src/main/ets/common                        
|   |---Constants.ets                        // 常量
|---/src/main/ets/pages                        
|   |---FloatWindowMainPage.ets              // 视图层-悬浮窗首页