AndroidSupportDesign之TabLayout使用详解

在上一篇博客《高逼格UI-ASD(Android Support Design)》中，我们大体的对TabLayout进行了一些初步的了解，这篇博客，单独拿出TabLayout来继续讲解是因为：纵观Android Support Design库的几个控件，除了诸如：FAB、SnackBar等几个小控件常用以外，也就TabLayout还ok了，其他的例如CollapsingToolbarLayout，这样的控件封装性太强了，只能固定那几个场景去使用(纯属个人见解)。 
那TabLayout呢？上一篇博客我们只是简单的了解一下，今天这篇博客我们就用TabLayout配合ViewPager使用以下。 
在开始之前，我们先来看看官网文档的说明,如何与ViewPager进行联动：

You should set a listener via setOnTabSelectedListener(OnTabSelectedListener) to be notified when any tab’s selection state has been changed. 
If you’re using a ViewPager together with this layout, you can use setTabsFromPagerAdapter(PagerAdapter) which will populate the tabs using the given PagerAdapter’s page titles. You should also use a TabLayout.TabLayoutOnPageChangeListener to forward the scroll and selection changes to this layout

恩，看起来很容易啊，简单翻译一下就是：

通过setOnTabSelectedListener设置一个监听器来响应选项卡的选择状态 
可以通过setTabsFromPagerAdapter来使用PagerAdapter的page title 
使用TabLayout.TabLayoutOnPageChangeListener来联动滑动

ok，大体就是这样，在大体的翻译过程中，其实已经把步骤列出来了，接下来我们只需要按照上面的步骤来编写我们的代码就OK啦。 
come on~，首先出场的是xml布局文件：

<code class="language-xml hljs  has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">LinearLayout</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span>
    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:app</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res-auto"</span>
    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:tools</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/tools"</span>
    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:layout_width</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"match_parent"</span>
    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:layout_height</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"match_parent"</span>
    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:orientation</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"vertical"</span>
    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">tools:context</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">".MainActivity"</span>></span>

    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">android.support.design.widget.TabLayout
</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:id</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"@+id/tl"</span>
        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:layout_width</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"match_parent"</span>
        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:layout_height</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"wrap_content"</span>
        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">app:tabIndicatorColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#FF00FF00"</span>
        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">app:tabSelectedTextColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#FF00FF00"</span>
        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">app:tabTextColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"#FF000000"</span>
        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">app:tabMode</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"scrollable"</span>
        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">app:tabGravity</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"center"</span>/></span>

    <span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">android.support.v4.view.ViewPager
</span>        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:id</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"@+id/viewpager"</span>
        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:layout_width</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"match_parent"</span>
        <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:layout_height</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"wrap_content"</span>/></span>

<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">LinearLayout</span>></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-width: 1px; border-right-style: solid; border-right-color: 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></ul>

恩，很简单，就是一个TabLayout和一个ViewPager,并且是上下排列的。

在Activity中，首先我们要find这两个控件：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">    mTabLayout = (TabLayout) findViewById(R.id.tl);
    mViewPager = (ViewPager) findViewById(R.id.viewpager);</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-width: 1px; border-right-style: solid; border-right-color: 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></ul>

为了演示程序，还需要两个伪数据来充当ViewPager的内容和title。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> String[] mTitle = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> String[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">20</span>];
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> String[] mData = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> String[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">20</span>];

{
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> i=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;i<<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">20</span>;i++) {
        mTitle[i] = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"title"</span> + i;
        mData[i] = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"data"</span> + i;
    }
}</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-width: 1px; border-right-style: solid; border-right-color: 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></ul>

下面，我们将要按照上面的步骤，一点点来撸代码啦： 
第一步，设置TabLayout的选项卡监听：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">mTabLayout.setOnTabSelectedListener(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> TabLayout.OnTabSelectedListener() {
            <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onTabSelected</span>(TabLayout.Tab tab) {
                mViewPager.setCurrentItem(tab.getPosition());
            }

            <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onTabUnselected</span>(TabLayout.Tab tab) {

            }

            <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onTabReselected</span>(TabLayout.Tab tab) {

            }
        });</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-width: 1px; border-right-style: solid; border-right-color: 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></ul>

当我们的tab选择时，让viewpager选中对应的item。 
第二步，设置Tab的标题来自PagerAdapter.getPageTitle()。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">mTabLayout.setTabsFromPagerAdapter(mAdapter);</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-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

第三步，设置TabLayout.TabLayoutOnPageChangeListener,给谁设置呢？当然是ViewPager了，怎么设置呢？

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> TabLayout.TabLayoutOnPageChangeListener listener =
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> TabLayout.TabLayoutOnPageChangeListener(mTabLayout);
mViewPager.addOnPageChangeListener(listener);</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-width: 1px; border-right-style: solid; border-right-color: 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></ul>

哦，原来TabLaout.TabLayoutOnPageChangeLisetener继承自OnPageChangeListener，不行来看：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">TabLayoutOnPageChangeListener</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">OnPageChangeListener</span> {</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-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

注意，这里是addOnPageChangeListener,也就是说，你还可以add N个Listener而不会被覆盖掉。 
到这里，步骤我们都走完了，但是别忘了给ViewPage设置Adapter。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">mViewPager.setAdapter(mAdapter);</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-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

最后是Adapter的代码：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> PagerAdapter mAdapter = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> PagerAdapter() {
        <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> CharSequence <span class="hljs-title" style="box-sizing: border-box;">getPageTitle</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> position) {
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> mTitle[position];
        }

        <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> <span class="hljs-title" style="box-sizing: border-box;">getCount</span>() {
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> mData.length;
        }

        <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> Object <span class="hljs-title" style="box-sizing: border-box;">instantiateItem</span>(View container, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> position) {
            TextView tv = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> TextView(MainActivity.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>);
            tv.setTextSize(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">30.</span>f);
            tv.setText(mData[position]);
            ((ViewPager) container).addView(tv);
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> tv;
        }

        <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">destroyItem</span>(ViewGroup container, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> position, Object object) {
            ((ViewPager) container).removeView((View) object);
        }

        <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> <span class="hljs-title" style="box-sizing: border-box;">isViewFromObject</span>(View view, Object object) {
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> view == object;
        }
    };</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-width: 1px; border-right-style: solid; border-right-color: 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><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li></ul>

运行一下代码，看看效果： 

是不是很简单？ 几行代码就搞定了这种效果，当然，你也可以选择自己重写View的方式实现，可以参考我的另一篇博客《打造史上最容易使用的Tab指示符——Indicator》。 
… 
如果，你感觉这就简单，那你也太容易满足啦，Google还给我们提供了一个方法，将这些步骤封装到一块，让我们开发者可以一步搞定。public void setupWithViewPager (ViewPager viewPager)，继续看看文档的说明：

The one-stop shop for setting up this TabLayout with a ViewPager.

This method will:

Add a ViewPager.OnPageChangeListener that will forward events to this TabLayout. 
Populate the TabLayout’s tabs from the ViewPager’s PagerAdapter. 
Set our TabLayout.OnTabSelectedListener which will forward selected events to the ViewPager

大体解释一下就是：

这个方法是addOnPageChangeListener和setOnTabSelectedListener的封装。

所以我们注释掉对应代码，替换成setupWithViewPager。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//        mTabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//            @Override</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//            public void onTabSelected(TabLayout.Tab tab) {</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//                mViewPager.setCurrentItem(tab.getPosition());</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//            }</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//            @Override</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//            public void onTabUnselected(TabLayout.Tab tab) {</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//            }</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//            @Override</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//            public void onTabReselected(TabLayout.Tab tab) {</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//            }</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//        });</span>
        mTabLayout.setTabsFromPagerAdapter(mAdapter);

<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//        final TabLayout.TabLayoutOnPageChangeListener listener =</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//                new TabLayout.TabLayoutOnPageChangeListener(mTabLayout);</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//        mViewPager.addOnPageChangeListener(listener);</span>
        mViewPager.setAdapter(mAdapter);
        mTabLayout.setupWithViewPager(mViewPager);
</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-width: 1px; border-right-style: solid; border-right-color: 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></ul>

效果还是上面的效果，但是代码量明显少了，仅需两行代码搞定。 
但是需要注意一下，setupWithViePager必须在ViewPager.setAdapter()之后调用！为什么呢？来源码找答案：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">setupWithViewPager</span>(ViewPager viewPager) {
    PagerAdapter adapter = viewPager.getAdapter();
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(adapter == <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throw</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> IllegalArgumentException(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"ViewPager does not have a PagerAdapter set"</span>);
    } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</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-width: 1px; border-right-style: solid; border-right-color: 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></ul>

首先去获取该ViewPager上的Adapter，如果没有Adapter，则抛出一个异常！ 
好了，到现在TabLayout和ViewPager一块使用的用法就讲解完了，相信还是非常简单的，仅仅两行代码就可以搞定。