> For the complete documentation index, see [llms.txt](https://kaleb-is-caleb.gitbook.io/infosys/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://kaleb-is-caleb.gitbook.io/infosys/fragments/untitled.md).

# Introduction

A [`Fragment`](http://developer.android.com/guide/components/fragments.html) is a self-contained component with its own user interface (UI) and life-cycle that can be reused in different parts of an app's UI. (A `Fragment` can also be used without a UI, in order to retain values across configuration changes, but this lesson does not cover that usage.)

A `Fragment` can be a *static* part of the UI of an `Activity`, which means that the `Fragment` remains on the screen during the entire life-cycle of the `Activity`. However, the UI of an `Activity` may be more effective if it adds or removes the `Fragment` *dynamically* while the `Activity` is running.

<div align="left"><img src="https://3048567368-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LtJ1GGrARY0aC3x6rVn%2F-LtJ3mo3X_ug7hshdSs3%2F-LtJ4ztmkV3zGfGY0SVK%2Fimage.png?alt=media&amp;token=b7cb1a3c-6afd-4371-b198-910950b17ee4" alt="Activity vs Fragment Life-Cycle"></div>

One example of a dynamic `Fragment` is the [`DatePicker`](https://developer.android.com/reference/android/widget/DatePicker.html) object, which is an instance of [`DialogFragment`](https://developer.android.com/reference/android/support/v4/app/DialogFragment.html), a subclass of [`Fragment`](https://developer.android.com/reference/android/app/Fragment.html). The date picker displays a dialog window floating on top of its `Activity` window when a user taps a button or an action occurs. The user can click **OK** or **Cancel** to close the `Fragment`.

Benefits of using Fragments

* Reuse a Fragment in more than one Activity
* Add or remove dynamically as needed
* Integrate a mini-UI within an Activity
* Retain data instances after a configuration change
* Represent sections of a layout for different screen sizes

&#x20;This practical introduces the [`Fragment`](https://developer.android.com/reference/android/app/Fragment.html) class and shows you how to include a `Fragment` as a static part of a UI, as well as how to use `Fragment` transactions to add, replace, or remove a `Fragment` dynamically.

### What you'll do

* Create a `Fragment` to use as a UI element that gives users a "yes" or "no" choice.
* Add interactive elements to the `Fragment` that enable the user to choose "yes" or "no".
* Include the `Fragment` for the duration of an `Activity`.
* Use `Fragment` transactions to add, replace, and remove a `Fragment` while an `Activity` is running.