all divs with same height in a flexbox with at the bottom

问题

I have the following html to build a grid with bootstrap 4.

<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">

<div class="row">
  <div class="col-sm-12 col-md-3">
    <div class="row">
      <div class="col-lg-12">
        here are different heights possible
      </div>
    </div>
    <div class="row align-items-end">
      <div class="col-lg-12 date">
        should always be at bottom (like the fourth date)
      </div>
    </div>
  </div>
  <div class="col-sm-12 col-md-3">
    <div class="row">
      <div class="col-lg-12">
        here are different heights possible
      </div>
    </div>
    <div class="row align-items-end">
      <div class="col-lg-12 date">
        should always be at bottom (like the fourth date)
      </div>
    </div>
  </div>
  <div class="col-sm-12 col-md-3">
    <div class="row">
      <div class="col-lg-12">
        here are different heights possible
        here are different heights possible
        here are different heights possible
      </div>
    </div>
    <div class="row align-items-end">
      <div class="col-lg-12 date">
        should always be at bottom (like the fourth date)
      </div>
    </div>
  </div>
  
</div>

I want to have the date always at the bottom of the second row. Maybe the picture explains the problem better. The first three dates are not in a line with the fourth date at the bottom of the flexbox:

回答1:

There is no way to equally align the content in children of separate flexbox parents. You can however make the columns also flexbox container using d-flex and then mt-auto (margin-top:auto) to push the dates to the bottom of the columns.

        <div class="col-sm-12 col-md-3 d-flex flex-column">
            <div class="row">
                <div class="col-lg-12">
                    here are different heights possible
                </div>
            </div>
            <div class="row mt-auto">
                <div class="col-lg-12 date">
                    date
                </div>
            </div>
        </div>

Demo: https://www.codeply.com/go/gLYW7liCfc

Also see: bootstrap 4 cards - vertical alignment body with variable header line rows

回答2:

You can stretch the date container to fill the remaining space of the row with flex:1 and align all the content to the bottom with align-items:flex-end :-)

I've amended your example slightly below, you don't actually need to extra .row within the wrapper - the col-lg-12 should be all you need to wrap onto next row.

I've only added the border:white 1px solid; so that you can see how my solution is working - you can just ignore that.

(You might need to view full screen to see the stacked elements working properly)!

.wrapper {
  display: flex;
  flex-direction: column;
  background: #1D3159;
  color: white;
}

.date {
  background: #1D3159;
  color: white;
  flex: 1;
  display: flex;
  align-items: flex-end;
  border:white 1px solid;
}

<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
<!-- just for this example -->

<div class="row">
  <div class="col-sm-12 col-md-3 wrapper">
    <div class="col-lg-12">
      here are different heights possible
    </div>
    <div class="col-lg-12 date">
      should always be at bottom (like the fourth date)
    </div>
  </div>
  <div class="col-sm-12 col-md-3 wrapper">
    <div class="col-lg-12">
      here are different heights possible
    </div>
    <div class="col-lg-12 date">
      should always be at bottom (like the fourth date)
    </div>
  </div>
  <div class="col-sm-12 col-md-3 wrapper">
    <div class="col-lg-12">
      here are different heights possible here are different heights possible here are different heights possible here are different heights possible here are different heights possible
    </div>
    <div class="col-lg-12 date">
      should always be at bottom (like the fourth date)
    </div>
  </div>
</div>

来源：https://stackoverflow.com/questions/54985467/all-divs-with-same-height-in-a-flexbox-with-at-the-bottom