Android Support Library V4 Framework Introduction and Use Guide

Android Support Library V4 Framework Introduction and Use Guide Android Support Library V4 (hereinafter referred to as SUPPORT LIBRARY V4) is a development tool set launched to solve the Android system version compatibility problem.This framework contains a series of categories and tools to help developers use the characteristics of high versions on the low -version Android system.This article will introduce the basic concepts and usage methods of SUPPORT LIBRARY V4, and provide some Java code examples to help you better understand and use the framework. 1. Overview of SUPPORT LIBRARY V4 Support Library V4 is a library that supports the Android system version from 2.3 (API 9) to the current latest version.It provides many practical functions related to the Android system, including but not limited to: fragment management, permissions processing, ViewPager, RecyclerView, animation effect, multimedia processing, etc.Using the SUPPORT LIBRARY V4, developers can use these high versions on the low -version Android system, and it is also more convenient for version to adapt. 2. Use SUPPORT LIBRARY V4 1. Import SUPPORT LIBRARY V4 to the Android project To use the SUPPORT LIBRARY V4, you need to add it to the dependency item of the project.You can import it into your Android project through the following steps: a. Open the project's `build.gradle` file. b. Add the following code to the block of `DependenCies` implementation 'com.android.support:support-v4:28.0.0' c. Synchronous items are changed by application dependency items. 2. Class and tools of using SUPPORT LIBRARARARARARARARARARAR Support Library V4 has a large number of categories and tools for developers. Here we use ViewPager as an example to introduce how to use this framework: a. Add ViewPager control in the XML layout file: <android.support.v4.view.ViewPager android:id="@+id/viewPager" android:layout_width="match_parent" android:layout_height="match_parent"/> b. Initialize the viewpager in the java code and set the adapter: ViewPager viewPager = findViewById(R.id.viewPager); FragmentPagerAdapter adapter = new FragmentPagerAdapter(getSupportFragmentManager()) { @Override public Fragment getItem(int position) { // Return to the corresponding position Fragment instance } @Override public int getCount() { // Return to ViewPager } }; viewPager.setAdapter(adapter); c. Use ViewPager in Activity or Fragment: ViewPager viewPager = getActivity().findViewById(R.id.viewPager); viewPager.setCurrentItem(position); Through the above steps, you can use ViewPager control on the low version of the Android system. Three, conclusion Through SUPPORT LIBRARY V4, developers can more conveniently achieve the Android system version compatibility and get more high version features on the lower version.This article briefly introduces the basic concepts and usage methods of SUPPORT LIBRARY V4, and use ViewPager as an example to show you how to use the framework.I hope this article can help you understand and use the SUPPORT LIBRARY V4.