活动是一个用户界面组件,主要用于构建应用程序的单个屏幕,并表示关注屏幕的主要焦点。一个活动可以一次托管一个或多个片段。随着平板电脑出现在更大的屏幕上,碎片是可重用的组件,它们附加到活动中并显示在活动中。从根本上讲,它是一项活动,可以实现更多模块化的活动设计。我们可以称片段是一种子活动。它始终由活动托管。它具有自己的布局和行为,并具有自己的生命周期回调。我们可以在活动运行时在活动中添加或删除片段。可以仅使用活动来开发UI,但这通常是一个坏主意,因为它们的代码以后无法在其他活动中重用,并且不能支持多个屏幕。活动是用户可以通过其进行交互的应用程序的UI,而Fragment是活动的一部分,它是活动内部的子活动,它具有自己的生命周期,该生命周期与活动生命周期平行。
活动生命周期
要了解更多信息,请参阅带有演示应用程序的Android中的“活动生命周期” 。
片段生命周期
要了解更多信息,请参阅Android中的Fragment Lifecycle
差异表
Activity |
Fragment |
---|---|
Activity is an application component that gives a user interface where the user can interact. | The fragment is only part of an activity, it basically contributes its UI to that activity. |
Activity is not dependent on fragment | Fragment is dependent on activity. It can’t exist independently. |
we need to mention all activity it in the manifest.xml file | Fragment is not required to mention in the manifest file |
We can’t create multi-screen UI without using fragment in an activity, | After using multiple fragments in a single activity, we can create a multi-screen UI. |
Activity can exist without a Fragment | Fragment cannot be used without an Activity. |
Creating a project using only Activity then it’s difficult to manage | While Using fragments in the project, the project structure will be good and we can handle it easily. |
Lifecycle methods are hosted by OS. The activity has its own life cycle. | Lifecycle methods in fragments are hosted by hosting the activity. |
Activity is not lite weight. | The fragment is the lite weight. |
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