Bootstrap根据屏幕大小显示行中元素的数量

Question

如果用户在中型设备（≥768px）上并且如果它们在（<768px）设备上，则我需要连续显示3个图像，然后我需要连续显示2个图像。如何使用Bootstrap或plain flex执行此操作。

Answer 1

使用Bootstrap列：

<div class="container">
    <div class="row">
        <div class="col-6 col-md-4">
            <img class="img-fluid" src="example.com/example.jpg"/>
        </div>
        <div class="col-6 col-md-4">
            <img class="img-fluid" src="example.com/example.jpg"/>
        </div>
        <div class="col-6 col-md-4">
            <img class="img-fluid" src="example.com/example.jpg"/>
        </div>
    </div>
</div>

https://getbootstrap.com/docs/4.0/layout/grid/

如果你想自己做，最好的做法是将<768px代码放在媒体查询之外，将> 768px放在一个内，这样页面就是“移动优先”。

<div class="flexbox">
    <img class="flex-image" src="example.com/example.jpg"/>
    <img class="flex-image" src="example.com/example.jpg"/>
    <img class="flex-image" src="example.com/example.jpg"/>
</div>

--

.flexbox {
    display: flex;
    flex-wrap: wrap;
}
.flex-image {
    flex: 0 0 50%;
}

@media screen and (min-width: 768px) {
    .flex-image {
        flex: 0 0 33%;
    }
}

Answer 2

像这样使用*-device-width

@media screen and (max-device-width:767px) {
  .contImg {
    width: 50%;
  }
}

@media screen and (min-device-width:768px) { 
  .contImg {
    width: 33.33%;
  }
}

* {
  box-sizing: border-box;
}

.contImg {
  float: left;
}

.contImg img {
  width: 100%;
  height: 250px;
}

@media screen and (max-device-width:767px) {
  .contImg {
    width: 50%;
  }
}

@media screen and (min-device-width:768px) { 
  .contImg {
    width: 33.33%;
  }
}

<div class="contImg">
  <img src="https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRDAYrQr9qgT2W00EV_CoCahFki3Vw4lSMNt81k9FCSTXoKT8TY2w">
</div>

<div class="contImg">
  <img src="https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQEnn9dYYZlciBKfaHCw17-dUgRPX3nq5_6-kV1ua-LIsId5g43uA">
</div>

<div class="contImg">
  <img src="https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSeY54SaYkaOxxyXlu_ng21EMIBZvJjnZBNQAOsIh_0_6Tvu9et">
</div>