Analysis of Core Technology Principles of Android Support Library View Pager Framework

Analysis of the core technical principles of Android Support Android Support Library View Page is a very commonly used control in Android development. It provides an interactive way to slide a switching page.This article will analyze the core technical principles of Android Support Library View Page framework and provide some Java code examples. 1. View Pages Overview View Page is a control that shows multiple pages. Users can switch the screen to switch the page.It is usually used to implement functions similar to picture browsers, navigation pages, guidance pages. 2. Basic usage of view pages The basic usage of View Page mainly includes the following three steps: 2.1 Definition of View Pages in the layout file Add a viewPager control to the layout file: <androidx.viewpager.widget.ViewPager android:id="@+id/viewPager" android:layout_width="match_parent" android:layout_height="match_parent" /> 2.2 The adapter implements data binding Create a subclass of Pageradapter and implement the following methods: public class MyPagerAdapter extends PagerAdapter { // Number of pages @Override public int getCount() { return 3; } // Define whether the page is generated by the object @Override public boolean isViewFromObject(View view, Object object) { return view == object; } // Initialize the page at the specified location @Override public Object instantiateItem(ViewGroup container, int position) { View view = LayoutInflater.from(container.getContext()).inflate(R.layout.item_page, container, false); // Initialize the page container.addView(view); return view; } // Destroy the page of the specified location @Override public void destroyItem(ViewGroup container, int position, Object object) { container.removeView((View) object); } } 2.3 Set the adapter to the View Pages In the code, set the adapter to the View Page: ViewPager viewPager = findViewById(R.id.viewPager); MyPagerAdapter adapter = new MyPagerAdapter(); viewPager.setAdapter(adapter); 3. Analysis of the core technical principle of View Pages The core technical principles of View Page mainly involve the following aspects: 3.1 Data structure View Page uses data structures to manage multiple pages.It stores the example of the page through a list.When the user slides the page, the View Page will dynamically load and destroy the page to maintain the reasonable use of memory. 3.2 page cache View Page supports page cache, and the number of cache is controlled by setting the cache.When the user slides to a new page, the View Page will pre -load the specified number of pages before and after, to improve the user experience. 3.3 Page recycling View Page uses page recycling mechanism to improve performance and memory utilization.When the user slides out of the screen page, the View Pages destroy the page and recycle resources for reuse. 3.4 page reuse View Page improves performance by reusing the page.When the user slides to a new page, the View Page will re -destroyed pages instead of re -creating a new page instance. 4 Conclusion By analyzing the core technical principles of Android Support Library View Pager framework, we learned that View Pages is a control of page sliding switching. It achieves high performance through technical means such as data structure, page cache, page recycling, and page reuse.Page switching effect.Developers can flexibly use View Pages to achieve various functions according to their needs and business scenarios.