In -depth analysis of the technical principle of ViewPager2 framework in Java Library

In -depth analysis of the technical principle of ViewPager2 framework in Java Library ViewPager2 is an important component in the Android Jetpack library, which is a new version of ViewPager.ViewPager2 has greatly improved its functions and performance compared to the previous ViewPager.This article will analyze the technical principles of the ViewPager2 framework to help readers better understand and apply this component. 1. Overview of viewpager2 ViewPager2 is a sliding paging view container, showing different pages by sliding the screen.It supports the sliding level and vertical direction, and can make smooth transition animation between pages.ViewPager2 can be used to create a variety of application scenarios such as guidance pages, picture browsers, news readers. 2. Use of viewpager2 Below is a simple example code that shows how to use ViewPager2 in an Activity to display the picture list: public class MainActivity extends AppCompatActivity { private List<Integer> imageList = Arrays.asList(R.drawable.image1, R.drawable.image2, R.drawable.image3); private ViewPager2 viewPager; private ImageAdapter imageAdapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); viewPager = findViewById(R.id.viewPager); imageAdapter = new ImageAdapter(imageList); viewPager.setAdapter(imageAdapter); } } In the above code, we created a list containing picture resource IDs.Then, set the picture list to ViewPager2 through the IMAGEADAPTER. 3. The principle of viewpager2 ViewPager2 is based on RecyclerView, and its bottom layer uses RecyclerView to manage the layout and scroll of the page.Similar to RecyclerView, ViewPager2 also uses the concept of viewholder to reuse the page view to improve performance. In ViewPager2, each page is a RecyclerView item.When sliding ViewPager2, it will call RecyclerView's rolling mechanism inside to achieve a smooth sliding effect.At the same time, ViewPager2 also supports the addition and delete page, and can monitor the switching event on the page. 4. The characteristics of viewpager2 -Do supports horizontal and vertical sliding. -Chiro the loop sliding of the page. -Profile the custom page to switch animation. -Cid the dynamic addition and delete page. 5. Precautions for using ViewPager2 -In the dependencies of viewpager2 in the Build.gradle file. groovy implementation 'androidx.viewpager2:viewpager2:1.0.0' -In need to create a suitable accessories to manage the page, the adapter needs to inherit from the RecyclerView.adapter. -The customized page switching animation can be achieved by registering PageTransFormer. -ViewPager2 does not support directly adding Fragments, but you can manage the Fragment page through FragmentStateadapter. Through the introduction of this article, we have a in -depth understanding of the technical principle of ViewPager2's framework.ViewPager2 is a powerful component that can help us quickly build a sliding paging view and enhance the user experience of the application.In practical applications, we can use the various characteristics of ViewPager2 according to specific needs, and we can refer to the official documentation and example code to further learn and master its usage.