Flex布局练习-骰子布局

学习来源：阮一峰的flex布局实战

骰子布局

<style type="text/css">
        /*div1是父级元素*/
		.div1{
     
     
			height: 90px;
			width: 90px;
			background-color: grey;
			display: flex; 
			display: -moz-flex; 
			display: -webkit-flex;
			overflow: hidden;
		}
		/*div2是子元素*/
		.div2{
     
     
			height: 30px;
			width: 30px;
			background-color: black;
		}
	</style>

(1)单项目

<div class="div1" style="align-items: flex-end;">
	<div class="div2"></div>
</div>

<div class="div1" style="justify-content: flex-end; align-items: flex-end;">
	<div class="div2"></div>
</div>

<div class="div1" style="justify-content: flex-end; align-items: center;">
	<div class="div2"></div>
</div>

<div class="div1" style="justify-content: center; align-items: flex-end;">
	<div class="div2"></div>
</div>

<div class="div1" style="justify-content: center; align-items: center;">
	<div class="div2"></div>
</div>

<div class="div1" style="justify-content: center;">
	<div class="div2"></div>
</div>

<div class="div1" style="justify-content: flex-end;">
	<div class="div2"></div>
</div>

<div class="div1" style="align-items: center;">
	<div class="div2"></div>
</div>

<div class="div1">
	<div class="div2"></div>
</div>

(2)双项目

<div class="div1" style="justify-content: space-between;">
	<div class="div2"></div>
	<div class="div2"></div>
</div>

<div class="div1" style="flex-direction: column; justify-content: space-between;">
	<div class="div2"></div>
	<div class="div2"></div>
</div>

<div class="div1" style="flex-direction: column; justify-content: space-between; align-items: center;">
	<div class="div2"></div>
	<div class="div2"></div>
</div>

<div class="div1">
	<div class="div2"></div>
	<div class="div2" style="align-self: center;"></div>
</div>

<div class="div1" style="flex-direction: column; justify-content: space-between; align-items: flex-end;">
	<div class="div2"></div>
	<div class="div2"></div>
</div>

<div class="div1" style="justify-content: space-between;">
	<div class="div2"></div>
	<div class="div2" style="align-self: flex-end;"></div>
</div>

(3)三项目

<div class="div1">
	<div class="div2"></div>
	<div class="div2" style="align-self: center;"></div>
	<div class="div2" style="align-self: flex-end;"></div>
</div>

(4)四项目

<div class="div1" style="justify-content: space-between;">
	<div style="width: 30px; height: 90px; display: flex; flex-wrap: wrap; align-content: space-between;">
		<div class="div2"></div>
		<div class="div2"></div>
	</div>
	<div style="width: 30px; height: 90px; display: flex; flex-wrap: wrap; align-content: space-between;">
		<div class="div2"></div>
		<div class="div2"></div>
	</div>
</div>

判断换行和使用嵌套：
特别说一下上面的四项目，这个就是用到了嵌套。
首先四个项目通过同方向且互相不重合的平移无法在一条直线上，
这就表明了肯定不是通过不换行(flex-wrap)+项目自身侧轴对齐(align-self)这两个属性实现的。
那就尝试一下用align-content+flex-wrap，通过换行来实现。align-content可以实现上下对齐的情况，
但是考虑横向对齐时，不论怎样设置justify-content发现也无法实现上述效果。
这里介绍了嵌套的思想，把第一行和第三行再看作是一个flex容器，这样就可以实现了。

<div class="div1" style="flex-wrap: wrap; align-content: space-between;">
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
</div>

(5)六项目

<div class="div1" style="flex-wrap: wrap;">
	<div style="display: flex; width: 90px; height: 30px;">
		<div class="div2"></div>
		<div class="div2"></div>
		<div class="div2"></div>
	</div>
	<div style="display: flex; justify-content: center; width: 90px; height: 30px;">
		<div class="div2"></div>
	</div>
	<div style="display: flex; justify-content: space-between; width: 90px; height: 30px;">
		<div class="div2"></div>
		<div class="div2"></div>
	</div>
</div>

很显然上面也是运用了嵌套的方法

<div class="div1" style="flex-wrap: wrap; align-content: space-between; flex-direction: column;">
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
</div>

<div class="div1" style="flex-wrap: wrap; align-content: space-between;">
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
</div>

(6)九项目

<div class="div1" style="flex-wrap: wrap;">
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
	<div class="div2"></div>
</div>