#鸿蒙通关秘籍#如何实现HarmonyOS Next中左右拖动切换图片效果？

要在HarmonyOS Next中实现左右拖动切换图片效果，通过创建三个Stack组件用于展示装修前后的图片对比，具体实现步骤如下：

1. 创建三个Stack组件。

   • 第一个和第三个Stack用于存放两张装修图片，将zIndex设置为1。
   • 第二个Stack存放按钮图片，并将zIndex设置为2，使得按钮覆盖在图片上层。

2. 将Image组件放置到Row容器中，并设置Row的宽度为状态变量，使用clip属性对Row进行裁剪。代码如下：

   Row() {
     Image($r('app.media.before_decoration'))
       .width($r('app.integer.decoration_width'))
       .height($r('app.integer.decoration_height'))
       .draggable(false)
     }
     .width(this.leftImageWidth)
     .clip(true)
     .zIndex(CONFIGURATION.ZINDEX1)
     .borderRadius({
       topLeft: $r('app.integer.borderradius'),
       bottomLeft: $r('app.integer.borderradius')
     })
   

3. 为右侧Image组件加上direction属性，使其从右向左进行布局，并设置clip属性从左开始裁剪。

   Row() {
    Image($r('app.media.after_decoration'))
      .width($r('app.integer.decoration_width'))
      .height($r('app.integer.decoration_height'))
      .draggable(false)
   }
   .width(this.rightImageWidth)
   .clip(true)
   .zIndex(CONFIGURATION.ZINDEX1)
   .direction(Direction.Rtl)
   .borderRadius({
    topRight: $r('app.integer.borderradius'),
    bottomRight: $r('app.integer.borderradius')
   })
   

4. 中间的按钮Image组件监听滑动手势事件，动态调整左右Image组件的宽度。

   Image($r('app.media.drag_button'))
     .width($r('app.integer.drag_button_image_width'))
     .height($r('app.integer.decoration_height'))
     .draggable(false)
     .gesture(
       PanGesture({ fingers: CONFIGURATION.PANGESTURE_FINGERS, distance: CONFIGURATION.PANGESTURE_DISTANCE })
         .onActionStart(() => {
           this.dragRefOffset = CONFIGURATION.INIT_VALUE;
         })
         .onActionUpdate((event: GestureEvent) => {
           this.dragRefOffset = event.offsetX;
           this.leftImageWidth = this.imageWidth + this.dragRefOffset;
           this.rightImageWidth = CONFIGURATION.IMAGE_FULL_SIZE - this.leftImageWidth;
           if (this.leftImageWidth >= CONFIGURATION.LEFT_IMAGE_RIGHT_LIMIT_SIZE) {
             this.leftImageWidth = CONFIGURATION.LEFT_IMAGE_RIGHT_LIMIT_SIZE;
             this.rightImageWidth = CONFIGURATION.RIGHT_IMAGE_RIGHT_LIMIT_SIZE;
           } else if (this.leftImageWidth <= CONFIGURATION.LEFT_IMAGE_LEFT_LIMIT_SIZE) {
             this.leftImageWidth = CONFIGURATION.LEFT_IMAGE_LEFT_LIMIT_SIZE;
             this.rightImageWidth = CONFIGURATION.RIGHT_IMAGE_LEFT_LIMIT_SIZE;
           }
         })
         .onActionEnd((event: GestureEvent) => {
           if (this.leftImageWidth <= CONFIGURATION.LEFT_IMAGE_LEFT_LIMIT_SIZE) {
             this.leftImageWidth = CONFIGURATION.LEFT_IMAGE_LEFT_LIMIT_SIZE;
             this.rightImageWidth = CONFIGURATION.RIGHT_IMAGE_LEFT_LIMIT_SIZE;
             this.imageWidth = CONFIGURATION.LEFT_IMAGE_LEFT_LIMIT_SIZE;
           } else if (this.leftImageWidth >= CONFIGURATION.LEFT_IMAGE_RIGHT_LIMIT_SIZE) {
             this.leftImageWidth = CONFIGURATION.LEFT_IMAGE_RIGHT_LIMIT_SIZE;
             this.rightImageWidth = CONFIGURATION.RIGHT_IMAGE_RIGHT_LIMIT_SIZE;
             this.imageWidth = CONFIGURATION.LEFT_IMAGE_RIGHT_LIMIT_SIZE;
           } else {
             this.leftImageWidth = this.imageWidth + this.dragRefOffset;
             this.rightImageWidth = CONFIGURATION.IMAGE_FULL_SIZE - this.leftImageWidth;
             this.imageWidth = this.leftImageWidth;
           }
         })
     )
   

通过以上步骤，实现了在HarmonyOS Next中左右拖动切换图片的效果。