如何从 twitter 引导程序中定位. btn-group？

Just declare your button links as inline-block instead of float:left and your text-align:center declaration will work, like so:

.btn-group a {
display:inline-block;
}

Demo: http://jsfiddle.net/EVmwe/3/

Edited: This has changed as of Bootstrap 3. See solution for Bootstrap 3 below.

Is adding a wrapping div out of the question?

Look at this example: http://jsfiddle.net/EVmwe/4/

Important part of the code:

/* a wrapper for the paginatior */
.btn-group-wrap {
text-align: center;
}


div.btn-group {
margin: 0 auto;
text-align: center;
width: inherit;
display: inline-block;
}


a {
float: left;
}

Wrapping the button group within a division, and setting the div to text-align center. The button group must also be overwritten to have display inline-block and inherited width.

Overwriting the anchors display to inline-block, and float: none, would also probably work, as @Andres Ilich said.

Update for Bootstrap 3

As of Bootstrap 3, you have alignment classes (as seen in the documentation). You now simply have to add the text-center class to a parent. Like so:

<div class="text-center">
<ul class="pagination">
<li class="disabled"><a href="#">&laquo;</a></li>
<li class="active"><a href="#">1</a></li>
<li><a href="#">2</a></li>
<li><a href="#">3</a></li>
<li><a href="#">4</a></li>
<li><a href="#">5</a></li>
<li><a href="#">&raquo;</a></li>
</ul>
</div>

See working example here: http://jsfiddle.net/EVmwe/409/

or add "pagination-centered", example:

<div class="btn-toolbar pagination-centered">
<div class="btn-group">
<a href=1 class="btn btn-small">1</a>
<a href=1 class="btn btn-small">2</a>
<a href=1 class="btn btn-small">3</a>
</div>
</div>

Since Twitter Bootstrap 3 there is no need for any workaround. Just specify the text-align: center for the parent element.

Adding text-center to a parent works for me (Bootstrap 3):

<div class="text-center">
<div class="btn-group">
<a href=1 class="btn btn-small">1</a>
<a href=1 class="btn btn-small">2</a>
<a href=1 class="btn btn-small">3</a>
</div>
</div>

In case anyone also wants to change the width of the .btn-group, you can do min-width rather than width. I did this:

HTML:

<div class="text-center">
<div class="btn-group">
<button class="btn">1</button>
<button class="btn">2</button>
</div>
</div>

CSS:

.btn-group {min-width: 90%;}
.btn {width: 50%;}

That set the btn-group width to 90% of text-center and each included button is 50% of the button group (45% of the text-center div).

In Bootstrap 3, you just need to structure as simple as following change

    <div class="btn-toolbar">
<div class="btn-group">
<button onclick="#" type="button" class="btn btn-default btn-sm">
Click 1
</button>
<button onclick="#" type="button" class="btn btn-default btn-sm">
Click 2
</button>
<button onclick="#" class="btn btn-default btn-sm" type="button">
Click 3
</button>
<button onclick="#" type="button" class="btn btn-default btn-sm">
Click 4
</button>
<button onclick="#" type="button" class="btn btn-default btn-sm">
Click 5
</button>
<button onclick="#" type="button" class="btn btn-default btn-sm">
Click 6
</button>
</div>
</div

And amend the style only this (override the bootstrap) which force float left so that you cannot force by margin or text center:

.btn-toolbar .btn-group {float:initial;}

This works for me, without much change.

I am using the following solution.

<div class="center-block" style="max-width:400px">
<a href="#" class="btn btn-success">Accept</a>
<a href="#" class="btn btn-danger"> Reject</a>
</div>

Throw the btn-group in a p tag and use text-align:center style for p {}

    p {
text-align: center;
}


<p>
<div class="btn-group" role="group" aria-label="...">
<button type="button" class="btn btn-default">Left</button>
<button type="button" class="btn btn-default">Middle</button>
<button type="button" class="btn btn-default">Right</button>
</div>
</p>

for bootstrap 4

<div class="text-center">
<div class="btn-group">
<a href="#" class="btn btn-primary">text 1</a>
<a href="#" class="btn btn-outline-primary">text 2</a>
</div>
</div>

This did the trick for me in Bootstrap v3.3

.btn-group {
margin: auto;
display: flex;
flex-direction: row;
justify-content: center;
}

<div class="btn-group mx-auto" role="group">
<a href="#" class="btn btn-outline-primary"> Button 1</a>
<a href="#" class="btn btn-outline-primary"> Button 2</a>
</div>