转载自/feiduclear_up/article/details/46500865
以上是三种不同效果的FloatingActionButton。XML布局代码如下：
<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; background: transparent; color: inherit; box-sizing: border-box; font-family: "Source Code Pro", monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal;"> <android<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.support</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.design</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.widget</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.FloatingActionButton</span>android:layout_width=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"wrap_content"</span>android:layout_height=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"wrap_content"</span>android:src=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"@drawable/ic_discuss"</span>/></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right: 1px solid rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul>
由于FloatingActionButton是重写ImageView的，所有FloatingActionButton拥有ImageView的一切属性。为了
控制FloatingActionButton的大小，背景颜色，阴影的深度等，我们可以通过如下属性来控制这些效果：
app:fabSize ：FloatingActionButton的大小，有两种赋值分别是 “mini” 和 “normal”，默认是“normal”.app:backgroundTint：FloatingActionButton的背景颜色，默认的背景颜色是Theme主题中的
<code class="hljs applescript has-numbering" style="display: block; padding: 0px; background: transparent; color: inherit; box-sizing: border-box; font-family: "Source Code Pro", monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal;"><<span class="hljs-property" style="box-sizing: border-box;">item</span> <span class="hljs-property" style="box-sizing: border-box;">name</span>=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"colorAccent"</span>><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">#ff0000</item></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right: 1px solid rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
颜色，不了解的童鞋们可以参考Android5.x新特性之 Toolbar和Theme的使用：/feiduclear_up/article/details/46457433。
3. app:elevation ：FloatingActionButton阴影的深度，默认是有阴影的，如果觉得默认阴影深度有点大，可以改变这个属性来修改阴影深度。
上面三个效果图的XML布局代码如下：
<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; background: transparent; color: inherit; box-sizing: border-box; font-family: "Source Code Pro", monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal;"> <LinearLayoutandroid:layout_width=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"match_parent"</span>android:layout_height=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"wrap_content"</span>android:orientation=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"horizontal"</span>><android<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.support</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.design</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.widget</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.FloatingActionButton</span>android:id=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"@+id/btn"</span>android:layout_width=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"wrap_content"</span>android:layout_height=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"wrap_content"</span>android:src=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"@drawable/ic_discuss"</span>app:fabSize=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"mini"</span> /><android<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.support</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.design</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.widget</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.FloatingActionButton</span>android:layout_width=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"wrap_content"</span>android:layout_height=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"wrap_content"</span>android:src=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"@drawable/ic_discuss"</span>/><android<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.support</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.design</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.widget</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.FloatingActionButton</span>android:layout_width=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"wrap_content"</span>android:layout_height=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"wrap_content"</span>android:src=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"@drawable/ic_discuss"</span>app:backgroundTint=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"#000af4"</span>app:fabSize=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"normal"</span>app:elevation=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"1dp"</span>/></LinearLayout></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right: 1px solid rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li></ul>
注意点
不能通过 android:background 属性来改变 FloatingActionButton的背景颜色，只能通过app:backgroundTint属性改变，因为FloatingActionButton是继承自ImageView的。
