Use WeChat applet to achieve carousel switching effect

Use WeChat applet to achieve carousel switching effect

WeChat applet is a lightweight application with simple and efficient development and use characteristics . In WeChat mini programs, it is a common requirement to achieve carousel switching effects. This article will introduce how to use the WeChat applet to achieve the carousel switching effect, and give specific code examples.

First, add a carousel component to the page file of the WeChat applet. For example, you can use the <swiper></swiper> tag to achieve the switching effect of the carousel. In this component, you can monitor the page switching action through the bindchange event. The specific code is as follows:

<swiper bindchange="changeImage">
  <block wx:for="{{images}}" wx:key="index"> 
    <swiper-item>
      <image src="{{item}}" mode="aspectFill"></image>
    </swiper-item>
  </block>
</swiper>

Among them, images is an array that contains the carousel The image address of the image. In the bindchange event, you can call a function changeImage to handle the switching event. In this function, the data of the page can be updated to achieve the switching effect of the carousel. For example, you can use the setData method to update the index value of the currently displayed image:

Page({
  data: {
    currentIndex: 0,
    images: [
      'url1',
      'url2',
      'url3'
    ]
  },
  changeImage: function (e) {
    this.setData({
      currentIndex: e.detail.current
    })
  }
})

Among them, currentIndex represents the index value of the currently displayed image, images Contains the image address of the carousel image. In the changeImage function, obtain the index value of the currently displayed image through e.detail.current, and use the setData method to update currentIndex value.

Next, you can dynamically change the style of the carousel image on the page according to the value of currentIndex to achieve a highlighting effect. For example, you can use the wx:if conditional judgment statement to determine whether the index value of the image is equal to currentIndex, and add the corresponding style:

<swiper bindchange="changeImage">
  <block wx:for="{{images}}" wx:key="index"> 
    <swiper-item>
      <image src="{{item}}" mode="aspectFill" 
             wx:if="{{index === currentIndex}}" 
             class="active-image"></image>
      <image src="{{item}}" mode="aspectFill" 
             wx:else 
             class="inactive-image"></image>
    </swiper-item>
  </block>
</swiper>

in the above code , use wx:if="{{index === currentIndex}}" to determine whether the current picture is the selected picture, if so, add class="active-image" Style, otherwise, add class="inactive-image" style.

Finally, in the style file of the WeChat applet, define two style classes active-image and inactive-image to distinguish between selected and unselected images. style. The specific sample code is as follows:

.active-image {
  border: 2px solid red;
}

.inactive-image {
  border: 2px solid #ccc;
}

The above code defines the style of the selected picture as a red border, and the style of the unselected picture as a gray border.

To sum up, this article introduces how to use the WeChat applet to achieve the carousel switching effect, and provides specific code examples. Through the above steps, you can easily implement the switching effect of the carousel in the WeChat mini program, adding more interaction and visual effects to the mini program.

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