blocks|key|645353|text|在大多数情况下，您既可以使用片段标记，也可以使用ID。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|645354|您可以在FragmentTransaction.add(Fragment+fragment,+String+tag+);中设置标签值。然后，您可以使用命令FragmentManager.findFragmentByTag(String+tab)查找有问题的片段。|offset|length|style|CODE|645355|entityMap^0|0|4|1K|25|19|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]|$D|N|E|O|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|P|8|@]|9|@]|A|$]]]|I|$]]

In most cases you can use the fragment tag as well as the ID. 
You can set the tag value in <code>FragmentTransaction.add(Fragment fragment, String tag );</code>.
Then you can use the command <code>FragmentManager.findFragmentByTag(String tab)</code> to find the fragment in question.

blocks|key|430746|text|正如Tom和其他人已经提到的，有一些方法可以将标记放在片段上并使用该标记进行识别。我在这些解决方案中遇到的一个后续问题是，直到片段与活动(或者实际上是FragmentManager)相关联时，它才会获得标记。如果需要在标记之前识别片段，该怎么办？|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|430747|到目前为止，我的解决方案都依赖于世界上最古老的(Java)技巧:创建一个最简单的模板片段，它在它的一个构造函数中接受一个id，并提供一个返回该id的getFragmentId()方法。然后，我让那些需要早期识别的片段扩展该模板，然后:瞧！问题解决了。|430748|不幸的是，这个解决方案可能需要一组模板片段，每种片段类型都需要一个模板片段，ListFragment、DialogFragment或普通旧式Fragment+(POFO?!)需要及早识别的人。但考虑到所提供的收益，我认为在片段的情况下这是可管理的。|430749|抱歉撕裂愈合的创伤:-)|430750|干杯!|430751|entityMap^0|23|F|0|22|F|0|12|C|1F|E|1Y|8|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|V|8|@$9|W|A|X|B|C]|$9|Y|A|Z|B|C]|$9|10|A|11|B|C]]|D|@]|E|$]]|$1|J|3|K|5|6|7|12|8|@]|D|@]|E|$]]|$1|L|3|M|5|6|7|13|8|@]|D|@]|E|$]]|$1|N|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|O|$]]

As Tom and others already mention, there are ways to put a tag on a fragment and use that tag for identification. A subsequent problem I've come across with those solutions is that the fragment doesn't get a tag until it's associated with the Activity (or, actually, the <code>FragmentManager</code>). What to do if one needs to identify a fragment before it has been tagged?

My solutions so far all rely on the oldest (Java) trick in the world: create a minimalistic template fragment which takes an id in one of it's constructors and provides a <code>getFragmentId()</code> method which returns that id. I then let those fragments that need early identification extend that template and; voila! Problem solved.

This solution might, unfortunately, require a set of template fragments, one for each fragment type, <code>ListFragment</code>, <code>DialogFragment</code> or plain old <code>Fragment</code> (POFO?!) that need early identification. But this is manageable in the case of fragments I think, considering the gains provided.

Sorry for tearing up healing wounds :-)

Cheers!

blocks|key|430810|text|事实证明，您可能不需要知道片段id。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|430811|从文档中：|430812|public+abstract+Fragment+findFragmentById+(int+id)

Finds+a+fragment+that+was+identified+by+the+given+id+either
when+inflated+from+XML+or+as+the+container+ID+when+added+in
a+transaction.|code-block|syntax|javascript|430813|重要的部分是“添加到事务中时作为容器ID”。|430814|所以：|430815|getSupportFragmentManager()
++++.beginTransaction()
++++.add(R.id.fragment_holder,+new+AwesomeFragment())
++++.commit();|430816|然后|430817|AwesomeFragment+awesome+=+(AwesomeFragment)
+++++getSupportFragmentManager()
++++++++++.findFragmentById(R.id.fragment_holder);|430818|将得到R.id.fragment_holder中包含的任何(令人敬畏的)片段。|430819|entityMap^0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|10|8|@]|9|@]|A|$]]|$1|M|3|N|5|F|7|11|8|@]|9|@]|A|$G|H]]|$1|O|3|P|5|6|7|12|8|@]|9|@]|A|$]]|$1|Q|3|R|5|F|7|13|8|@]|9|@]|A|$G|H]]|$1|S|3|T|5|6|7|14|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|V|$]]

Turns out you may not need to know the fragment id.

From the docs:

<pre><code>public abstract Fragment findFragmentById (int id)

Finds a fragment that was identified by the given id either
when inflated from XML or as the container ID when added in
a transaction.
</code></pre>

The important part is "as the container ID when added in a transaction".

so:

<pre><code>getSupportFragmentManager()
 .beginTransaction()
 .add(R.id.fragment_holder, new AwesomeFragment())
 .commit();
</code></pre>

and then

<pre><code>AwesomeFragment awesome = (AwesomeFragment)
 getSupportFragmentManager()
 .findFragmentById(R.id.fragment_holder);
</code></pre>

will get you whatever (awesome) fragment is held in R.id.fragment_holder.

blocks|key|431276|text|除了Tom的回答，除了add方法，replace方法还支持片段标签。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|431277|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

In addition to Tom's answer, replace method also supports the fragment tag, in addition to add method.

blocks|key|645582|text|使用以下内容：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|645583|要添加片段，请执行以下操作：|645584|getFragmentManager().beginTransaction().add(R.id.fragment_container,+fragmentToBeAdded,+tag).commit();|code-block|syntax|javascript|645585|要标识现有片段，请执行以下操作：|645586|getFragmentManager().findFragmentByTag(fragmentName);|645587|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Use the following:

To add a fragment: 

<pre><code>getFragmentManager().beginTransaction().add(R.id.fragment_container, fragmentToBeAdded, tag).commit();
</code></pre>

To identify existing fragment:

<pre><code>getFragmentManager().findFragmentByTag(fragmentName);
</code></pre>

How can I set a <code>Fragment</code>'s <code>Id</code> so that I can use <code>getSupportFragmentManager().findFragmentById(R.id.--)</code>?

Android - Set fragment id

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如何设置Fragment的Id才能使用getSupportFragmentManager().findFragmentById(R.id.--)

问Android -设置片段id
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