blocks|key|2654758|text|您应该在导航编辑器(导航图的xml文件)中单击"text“选项卡，然后添加：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2654759|tools:layout="@layout/layout_name"|code-block|syntax|javascript|2654760|在目标元素内部。|2654761|应该是这样的：|2654762|<fragment
++++android:id="@%2Bid/someFragment"
++++android:name="com.freesoulapps.navigationtest.fragments.SomeFragment"
++++android:label="Some+Fragment"
++++tools:layout="@layout/layout_name">
</fragment>|2654763|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|D|7|S|8|@]|9|@]|A|$E|F]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

You should click on "text" tab in navigation editor (xml file of the navigation graph), and add:

<pre><code>tools:layout="@layout/layout_name"
</code></pre>

inside destination element.

Should be something like this:

<pre><code>&lt;fragment
 android:id="@+id/someFragment"
 android:name="com.freesoulapps.navigationtest.fragments.SomeFragment"
 android:label="Some Fragment"
 tools:layout="@layout/layout_name"&gt;
&lt;/fragment&gt;
</code></pre>

blocks|key|7297|text|还有另一种在导航xml中进行预览的方法。首先添加您的xml片段|type|unstyled|depth|inlineStyleRanges|entityRanges|data|7298|tools:context="com.packagename.nameFragment"|code-block|syntax|javascript|7299|​|7300|📷|atomic|offset|length|7301|7302|就是这样|7303|如果进入导航文件，您可以在选择和导航编辑器中看到预览|7304|7305|7306|7307|7308|如果你看一下代码是自动编写的|7309|tools:layout="@layout/layout_name"|7310|对我来说，在导航编辑器中添加片段之前进行预览更符合逻辑。可能有自动添加工具的方法:在布局中添加上下文|7311|自动补全不建议用于工具:上下文片段仅建议工具:上下文活动主机，因此您需要写入片段的名称...如果有人有这方面的诀窍|7312|了解有关工具的更多信息:context：enter+link+description+here|7313|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/6e3e0740a1c0389c49a4e20320dad506.png|imageAlt|1|https://ask.qcloudimg.com/http-save/yehe-900000/6c148da3d32f4901f2d976e75f488571.png|2|https://ask.qcloudimg.com/http-save/yehe-900000/0551f4b8576ddf71bd2c354cd7487883.png|3|LINK|MUTABLE|url|https://stackoverflow.com/questions/11078487/whats-toolscontext-in-android-layout-files^0|0|0|0|0|1|0|0|0|0|0|0|0|1|1|0|0|1|2|0|0|0|0|0|0|K|R|3|0^^$0|@$1|2|3|4|5|6|7|1O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|1P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|1Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|K|7|1R|8|@]|9|@$L|1S|M|1T|1|1U]]|A|$]]|$1|N|3|H|5|6|7|1V|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|1W|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1X|8|@]|9|@]|A|$]]|$1|S|3|H|5|6|7|1Y|8|@]|9|@]|A|$]]|$1|T|3|J|5|K|7|1Z|8|@]|9|@$L|20|M|21|1|22]]|A|$]]|$1|U|3|J|5|K|7|23|8|@]|9|@$L|24|M|25|1|26]]|A|$]]|$1|V|3|H|5|6|7|27|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|28|8|@]|9|@]|A|$]]|$1|Y|3|Z|5|D|7|29|8|@]|9|@]|A|$E|F]]|$1|10|3|11|5|6|7|2A|8|@]|9|@]|A|$]]|$1|12|3|13|5|6|7|2B|8|@]|9|@]|A|$]]|$1|14|3|15|5|6|7|2C|8|@]|9|@$L|2D|M|2E|1|2F]]|A|$]]|$1|16|3|-4|5|6|7|2G|8|@]|9|@]|A|$]]]|17|$18|$5|19|1A|1B|A|$1C|1D|1E|-4]]|1F|$5|19|1A|1B|A|$1C|1G|1E|-4]]|1H|$5|19|1A|1B|A|$1C|1I|1E|-4]]|1J|$5|1K|1A|1L|A|$1M|1N]]]]

there is another way to have the preview in navigation xml.
First go in your xml fragment add 

<pre><code>tools:context="com.packagename.nameFragment"
</code></pre>

<a href="https://i.stack.imgur.com/bm9Kh.png" rel="noreferrer"><img src="https://i.stack.imgur.com/bm9Kh.png" alt="exemple for my frag layout"></a>

And that's it

if you go in your navigation file you can see the preview inside the selection and the navigation editor

<a href="https://i.stack.imgur.com/qmldF.png" rel="noreferrer"><img src="https://i.stack.imgur.com/qmldF.png" alt="enter image description here"></a>
<a href="https://i.stack.imgur.com/cqbyR.png" rel="noreferrer"><img src="https://i.stack.imgur.com/cqbyR.png" alt="enter image description here"></a>

And if you look in the code is auto write

<pre><code>tools:layout="@layout/layout_name"
</code></pre>

For me is more logic to have the preview before add the fragment in the navigation editor.
May be there are method for add automatically the tools:context in the layout

Autocompletation not suggest for tools:context Fragment only suggest the tools:context Activity host so you need to write the fragment's name... if someone have a trick for this

learn more about tools:context :
<a href="https://stackoverflow.com/questions/11078487/whats-toolscontext-in-android-layout-files">enter link description here</a>

blocks|key|6609|text|只需将tools:layout="fragmentname“添加到预览不可见的每个片段。示例：-|type|unstyled|depth|inlineStyleRanges|entityRanges|data|6610|<navigation+
++++xmlns:android="http://schemas.android.com/apk/res/android"
++++xmlns:app="http://schemas.android.com/apk/res-auto"
++++xmlns:tools="http://schemas.android.com/tools"
++++android:id="@%2Bid/nav_graph"
++++app:startDestination="@id/startFragment">

++++<fragment
++++++++android:id="@%2Bid/pickupFragment"
++++++++android:name="com.example.cup_cake.PickupFragment"
++++++++android:label="fragment_pickup"
++++++++tools:layout="@layout/fragment_pickup"+/>

</navigation>|code-block|syntax|javascript|6611|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Just add
tools:layout=&quot;fragmentname&quot;
to every fragment whose preview is not visible.
Example:-
<pre><code>&lt;navigation 
 xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
 xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
 xmlns:tools=&quot;http://schemas.android.com/tools&quot;
 android:id=&quot;@+id/nav_graph&quot;
 app:startDestination=&quot;@id/startFragment&quot;&gt;

 &lt;fragment
 android:id=&quot;@+id/pickupFragment&quot;
 android:name=&quot;com.example.cup_cake.PickupFragment&quot;
 android:label=&quot;fragment_pickup&quot;
 tools:layout=&quot;@layout/fragment_pickup&quot; /&gt;

&lt;/navigation&gt;
</code></pre>

I am interested to try the Navigation graph showed in the Android Studio. But I got the preview unavailable after I import the <a href="https://developer.android.com/jetpack/docs/ComponentsBasicSample.zip" rel="noreferrer">google sample</a>

I used the Android Studio 3.2 Preview Canary 16

<a href="https://i.stack.imgur.com/stHfy.png" rel="noreferrer"><img src="https://i.stack.imgur.com/stHfy.png" alt="enter image description here"></a>

<pre><code>&lt;navigation xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 app:startDestination="@+id/launcher_home"&gt;

 &lt;fragment
 android:id="@+id/launcher_home"
 android:name="com.android.samples.arch.componentsbasicsample.StartFragment"
 android:label="Home"&gt;

 &lt;action
 android:id="@+id/end_action"
 app:destination="@id/end_dest" /&gt;

 &lt;/fragment&gt;

 &lt;fragment
 android:id="@+id/end_dest"
 android:name="com.android.samples.arch.componentsbasicsample.EndFragment"
 android:label="End"
 &gt;

 &lt;/fragment&gt;
&lt;/navigation&gt;
</code></pre>

Update on 10/6/2018:

Even I rebuild the project it doesn't work. But if added new screen, it showed the new one in preview mode

<a href="https://i.stack.imgur.com/375I7.png" rel="noreferrer"><img src="https://i.stack.imgur.com/375I7.png" alt="enter image description here"></a>

Navigation Preview unavailable in Android Studio 3.2 Preview

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我有兴趣尝试一下Android Studio中显示的导航图表。但是在我导入之后，预览变得不可用我使用的是Android Studio 3.2 Preview Canary 16​​<navigation xmlns:android="http://schemas.android.com/apk/res/android"...

问导航预览在Android Studio 3.2预览中不可用
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问导航预览在Android Studio 3.2预览中不可用EN