Rumah >applet WeChat >Pembangunan program mini >微信小程序中实现瀑布流布局和无限加载

微信小程序中实现瀑布流布局和无限加载

迷茫
迷茫asal
2017-03-25 16:01:051603semak imbas


c4584840437e61edb6bca73028be46125988b9a629602a796578dc4309c6bd62
 a606f4cc534702ec9474dde0bc328efaf8e950ebc6c1ea27f76cf997b9216fe6de5f4c1163741e920c998275338d29b2

我们可以在Page中通过数据绑定,来传递要加载的图片信息到wxml中,让dc0870658837139040642baa5555a380组件去加载图片资源,然后当图片加载完成的时候,通过bindload指定的事件处理函数来做进一步处理。

我们来看一下Page文件中定义的onImageLoad函数。在其中,我们可以从传入的事件对象e上,获取到dc0870658837139040642baa5555a380组件的丰富信息,包括通过它加载进来的图片的实际大小。然后我们将图片按照页面上实际需要显示的尺寸,计算出同比例缩放后的尺寸。接着,我们可以根据左右两列目前累积的内容高度,来决定把当前加载进来的图片放到哪一边。

let col1H = 0;let col2H = 0;

Page({    data: {        scrollH: 0,        imgWidth: 0,        loadingCount: 0,        images: [],        col1: [],        col2: []
   },    onLoad: function () {
       wx.getSystemInfo({            success: (res) => {                
       let ww = res.windowWidth;                
       let wh = res.windowHeight;                
       let imgWidth = ww * 0.48;                
       let scrollH = wh;                
       this.setData({                    
       scrollH: scrollH, 
       imgWidth: imgWidth
               });                //加载首组图片
               this.loadImages();
           }
       })
   },    onImageLoad: function (e) {        
   let imageId = e.currentTarget.id;        
   let oImgW = e.detail.width;         //图片原始宽度
       let oImgH = e.detail.height;        //图片原始高度
       let imgWidth = this.data.imgWidth;  //图片设置的宽度
       let scale = imgWidth / oImgW;        //比例计算
       let imgHeight = oImgH * scale;      //自适应高度

       let images = this.data.images;        let imageObj = null;        
       for (let i = 0; i < images.length; i++) {            let img = images[i];            
       if (img.id === imageId) {
               imageObj = img;                break;
           }
       }

       imageObj.height = imgHeight;        
       let loadingCount = this.data.loadingCount - 1;        
       let col1 = this.data.col1;        
       let col2 = this.data.col2;        //判断当前图片添加到左列还是右列
       if (col1H <= col2H) {
           col1H += imgHeight;
           col1.push(imageObj);
       } else {
           col2H += imgHeight;
           col2.push(imageObj);
       }        let data = {            
       loadingCount: loadingCount,            col1: col1,            col2: col2
       };        //当前这组图片已加载完毕,则清空图片临时加载区域的内容
       if (!loadingCount) {
           data.images = [];
       }        this.setData(data);
   },    loadImages: function () {        let images = [
           { pic: "../../images/1.png", height: 0 },
           { pic: "../../images/2.png", height: 0 },
           { pic: "../../images/3.png", height: 0 },
           { pic: "../../images/4.png", height: 0 },
           { pic: "../../images/5.png", height: 0 },
           { pic: "../../images/6.png", height: 0 },
           { pic: "../../images/7.png", height: 0 },
           { pic: "../../images/8.png", height: 0 },
           { pic: "../../images/9.png", height: 0 },
           { pic: "../../images/10.png", height: 0 },
           { pic: "../../images/11.png", height: 0 },
           { pic: "../../images/12.png", height: 0 },
           { pic: "../../images/13.png", height: 0 },
           { pic: "../../images/14.png", height: 0 }
       ];        let baseId = "img-" + (+new Date());       
        for (let i = 0; i < images.length; i++) {
           images[i].id = baseId + "-" + i;
       }        this.setData({            
       loadingCount: images.length,            images: images
       });
   }

})
  if (col1H <= col2H) {
            col1H += imgHeight;
            col1.push(imageObj);
        } else {
            col2H += imgHeight;
            col2.push(imageObj);
        }        let data = {            loadingCount: loadingCount,            col1: col1,            col2: col2
        };        //当前这组图片已加载完毕,则清空图片临时加载区域的内容
        if (!loadingCount) {
            data.images = [];
        }        this.setData(data);
    },    loadImages: function () {        let images = [
            { pic: "../../images/1.png", height: 0 },
            { pic: "../../images/2.png", height: 0 },
            { pic: "../../images/3.png", height: 0 },
            { pic: "../../images/4.png", height: 0 },
            { pic: "../../images/5.png", height: 0 },
            { pic: "../../images/6.png", height: 0 },
            { pic: "../../images/7.png", height: 0 },
            { pic: "../../images/8.png", height: 0 },
            { pic: "../../images/9.png", height: 0 },
            { pic: "../../images/10.png", height: 0 },
            { pic: "../../images/11.png", height: 0 },
            { pic: "../../images/12.png", height: 0 },
            { pic: "../../images/13.png", height: 0 },
            { pic: "../../images/14.png", height: 0 }
        ];        let baseId = "img-" + (+new Date());        
        for (let i = 0; i < images.length; i++) {
            images[i].id = baseId + "-" + i;
        }        this.setData({            loadingCount: images.length,            images: images
        });
    }
})


这里是显示在两列图片的wxml代码,我们可以看到在050e2adc6de973d5d8d682f9c1b9f656组件上,我们通过使用bindscrolltolower设置了事件监听函数,当滚动到底部的时候,会触发loadImages去再加载下一组的图片数据,这样就形成了无限的加载:

<scroll-view scroll-y="true" style="height:{{scrollH}}px" bindscrolltolower="loadImages">
  <view style="width:100%">
    <view class="img_item">
      <view wx:for="{{col1}}" wx:key="id">
        <image src="{{item.pic}}" style="width:100%;height:{{item.height}}px"></image>
      </view>
    </view>
    <view class="img_item">
      <view wx:for="{{col2}}" wx:key="id">
        <image src="{{item.pic}}" style="width:100%;height:{{item.height}}px"></image>
      </view>
    </view>
  </view>
</scroll-view>


Atas ialah kandungan terperinci 微信小程序中实现瀑布流布局和无限加载. Untuk maklumat lanjut, sila ikut artikel berkaitan lain di laman web China PHP!

Kenyataan:
Kandungan artikel ini disumbangkan secara sukarela oleh netizen, dan hak cipta adalah milik pengarang asal. Laman web ini tidak memikul tanggungjawab undang-undang yang sepadan. Jika anda menemui sebarang kandungan yang disyaki plagiarisme atau pelanggaran, sila hubungi admin@php.cn
Artikel sebelumnya:picker滚动选择器Artikel seterusnya:微信小程序支付流程