The technical principles and use of the technical principles of Android SUPPPORT LIBRARY VIEW PAGER framework (Technical Principles and USAGE Explanation of Android Support Library View Pages))

The technical principles and detailed explanations of the technical principles of Android SUPPORT LIBRARY View Page Android Support Library View Pages is a framework commonly used in Android development to achieve sliding page switching effects.This article will introduce the technical principles and use methods of the framework in detail. Overview: Android Support Library View Pages is based on Android Support Library extensions. It provides developers with convenient page switching implementation methods by supporting page sliding, animation effects, pre -load pages. Technical principle: The implementation principles of Android Support Library View Pages mainly depend on the following core components: 1. ViewPager class: ViewPager is the core class to achieve page switching effects. It can switch between the page through the left and right sliding.Developers can add different pages to ViewPager by customizing adapter. 2. Pageradapter class: Pageradapter is the adapter of the ViewPager to manage the creation, destruction and data binding of pages in ViewPager.Developers need to inherit the Pageradapter class to implement the custom page adapter, and rewrite the method according to the needs to provide the correct page switching effect and data display. 3. Fragment class: Fragment is the basic unit for constructing reusable and easy -to -manage UI components in Android.By adding different Fragment to the ViewPager, complex page layout and switching effects can be achieved. Instructions: The following are the basic steps of using Android Support Library View Pages: 1. Add the support library dependencies: In the project's built.gradle file, add the following dependencies: dependencies { implementation 'com.android.support:support-v4:xxx' } 2. Add ViewPager to the layout file: In the layout file that needs to be displayed on the display page, the layout definition of the ViewPager is added: <android.support.v4.view.ViewPager android:id="@+id/viewPager" android:layout_width="match_parent" android:layout_height="match_parent" /> 3. Create Pageradapter: Create a custom Pageradapter in the code, and implement the method by inheriting the Pageradapter class: public class CustomPagerAdapter extends PagerAdapter { private List<Fragment> fragments; public CustomPagerAdapter(List<Fragment> fragments) { this.fragments = fragments; } @Override public int getCount() { return fragments.size(); } @Override public boolean isViewFromObject(@NonNull View view, @NonNull Object object) { return view == object; } @NonNull @Override public Object instantiateItem(@NonNull ViewGroup container, int position) { Fragment fragment = fragments.get(position); // Page initialization and added to the container return fragment; } @Override public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) { // page destruction super.destroyItem(container, position, object); } } 4. Set ViewPager adapter: In Activity or Fragment, set the ViewPager adapter in the following ways: ViewPager: ViewPager viewPager = findViewById(R.id.viewPager); CustomPagerAdapter adapter = new CustomPagerAdapter(fragments); viewPager.setAdapter(adapter); 5. Page switching monitoring: If you need to listen to the page switching incident, you can add a monitor by the adDONPAGECHANGENER method of ViewPager: viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() { @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { // Page rolling medium back } @Override public void onPageSelected(int position) { // Page selection back adjustment } @Override public void onPageScrollStateChanged(int state) { // Page rolling state changes back } }); Summary: Android Support Library View Pager framework provides developers with a convenient solution to developers to achieve page switching effects by providing core components such as ViewPager and Pageradapter.Developers can achieve customized page layouts and switching effects by defining their own Pageradapter and Fragment, thereby meeting various needs.