Fragment和FragmentActivity的关系

最新推荐文章于 2016-04-15 08:39:00 发布

Lance_Yao

最新推荐文章于 2016-04-15 08:39:00 发布

阅读量690

点赞数

分类专栏： Android 文章标签： android Fragment FragmentActivity

Android 专栏收录该内容

10 篇文章

订阅专栏

本文解释了Android中Fragment与FragmentActivity的区别。Fragment是Activity的一部分，有自己的生命周期和输入事件，可以在Activity运行时添加或移除。FragmentActivity是为支持旧版平台而引入的，用于容纳Fragment，提供了与Fragment交互的API。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

原文地址：http://stackoverflow.com/questions/10609268/difference-between-fragment-and-fragmentactivity

A Fragment is a section of an Activity, which has:

its own lifecycle
receives its own input events
can be added or removed while the Activity is running.

A Fragment must always be embedded in an Activity.

Fragments are not part of the API prior to HoneyComb (3.0). If you want to use Fragments in an app targeting a platform version prior to HoneyComb, you need to add the Support Package to your project and use the FragmentActivity to hold your Fragments. The FragmentActivity class has an API for dealing with Fragments, whereas the Activity class, prior to HoneyComb, doesn't.

If your project is targeting HoneyComb or newer only, you should use Activity and not FragmentActivity to hold your Fragments.

Some details:

Use android.app.Fragment with Activity. Use android.support.v4.app.Fragment with FragmentActivity. Don't add the support package Fragment to an Activity as it will cause an Exception to be thrown.

A thing to be careful with: FragmentManager and LoaderManager have separate support versions for FragmentActivity:

If you are using a Fragment in an Activity (HoneyComb and up), call

getFragmentManager() to get android.app.FragmentManager
getLoaderManager() to get android.app.LoaderManager

if you are using a Fragment in a FragmentActivity (pre-HoneyComb), call:

getSupportFragmentManager() to get android.support.v4.app.FragmentManager.
getSupportLoaderManager() to get android.support.v4.app.LoaderManager

so, dont do

myFragmentActivity.getLoaderManager()//don't do this, do myFragmentActivity.getSupportLoaderManager()

android.app.FragmentManager fm = myFragmentActivity.getSupportFragmentManager()//don't do this, do android.support.v4.app.FragmentManager fm = myFragmentActivity.getSupportFragmentManager()

Also useful to know is that while a fragment has to be embedded in an Activity it doesn't have to be part of the Activity layout. It can be used as an invisible worker for the activity, with no UI of its own.