using a flex item as a flex container

问题

I wanted to use flexbox with a column layout, but I wanted the top n - 1 flex items to be pinned to the top and the nth flex item to be pinned to the bottom of the main flex container area.

I solved this by using the nth flex item to also be a new flexbox/flex container using justify-content: flex-end, but I couldn't find any examples that were doing this - so is this a correct/acceptable solution according to the standard and, if not, how would I otherwise go about this with flexbox?

Here's a quick example:

.flex-container {
  display: -webkit-flex;
  display: flex;
  -webkit-flex-direction: column;
  flex-direction: column;
  width: 300px;
  height: 240px;
  background-color: Silver;
}
.flex-container-bottom {
  display: -webkit-flex;
  display: flex;
  -webkit-flex-direction: column;
  flex-direction: column;
  width: 300px;
  height: 240px;
  background-color: orange;
  -webkit-justify-content: flex-end;
  -ms-flex-pack: end;
  justify-content: flex-end;
}
.flex-item {
  background-color: DeepSkyBlue;
  width: 100px;
  height: 100px;
  margin: 5px;
}
.flex-item-bottom {
  background-color: red;
  width: 100%;
  height: 50px;
}

<div class="flex-container">
  <div class="flex-item">flex item 1</div>
  <div class="flex-item flex-container-bottom">
    <div class="flex-item-bottom">flex item 2</div>
  </div>
</div>

回答1:

The spec isn't very clear on this, but it states that "Each in-flow child of a flex container becomes a flex item, and each contiguous run of text that is directly contained inside a flex container is wrapped in an anonymous flex item." This seems to imply that if I put a flex container inside another flex container that the inner flex container would also implicitly become a flex item for its containing flex container even if this is not explicitly defined. Example 1 of the specification shows a flex container within a flex container and assuming it is legal syntax it follows that my use case may also be legal, but the section with example 1 is marked as non-normative... (╯°□°）╯︵ ┻━┻... At this point I'm just going to assume this is correct.

回答2:

It's hard to say that your use of flex-end is wrong because you're getting the desired effect, but there's an easier way to do it.

Try using:

.flex-container{
   display: flex;
   justify-content: space-between;
   flex-direction: column;
}

justify-content: space-between; forces your flex items to spread out as much as possible in the flex container.

This is the reference guide I use whenever doing anything with flexboxes: https://css-tricks.com/snippets/css/a-guide-to-flexbox/

回答3:

You can also try this this will make your last item to stick to bottom of your parent container

.flex-container{
    position:relative;
   }
 .flex-item-bottom{
    position:absolute;
    bottom:0;
 }

来源：https://stackoverflow.com/questions/31143181/using-a-flex-item-as-a-flex-container

标签

html

css

flexbox