Learn the technical principles of the technical principles of Android support library frame

The technical principles and examples of Android SUPPORT LIBRARY FRAGMENT framework introduction: Android Support Library is a set of libraries provided to solve the compatibility of the version of the Android system. Among them, the Fragment framework is one of the key components.Fragment can be understood as a reusable UI component that can be embedded in Activity, making the interface more modular and flexible.This article will learn the technical principles of Android SUPPORT LIBRARY FRAGMENT framework and provide corresponding Java code examples. 1. The basic concept of fragment Fragment is the earliest component similar to Activity that Android, which provides a more flexible user interface model.Fragment can be regarded as a modular part in an Activity. One Activity can contain multiple frames. One application can have multiple Activity. By using Fragment in Activity to build a more complex interface. Second, use support library Android provides SUPPORT LIBRARY to be compatible with the old version of the old version.To use the Support Library Fragment, you first need to add dependencies to the SUPPORT-FRAGMENT package in the built.gradle file: groovy implementation 'androidx.fragment:fragment:1.3.5' 3. Fragment's life cycle Fragment has its own life cycle, which is relatively independent of the life cycle of Activity. The life cycle of Fragment includes the following key methods: 1. Onattach (): Calling when Fragment and Activity are associated. 2. Oncreate (): Calling when Fragment was created. 3. OncreateView (): Create a Fragment view. 4. OnviewCreated (): Fragment's view has been created. 5. Oncreate () method associated with the ActivityCreated (): The oncreate () method associated with the frame is called when the Activity method is called. 6. OnStart (): Calling when Fragment can be visible. 7. Onresume (): Fragment can be called when interacting. 8. Onpause (): Fragment lost the focus or calls when stopped interacting. 9. OnStop (): Fragment is called when not visible. 10. ONDESTROYView (): The view of the frame was called when the view was removed. 11. ONDESTROY (): Calling when Fragment was destroyed. 12. ONDETACH (): Fragment is called when the association is lifted with Activity. 4. Create Fragment Creating Fragment needs to inherit the Fragment class, and rewrite some key methods. Below is a simple example: public class MyFragment extends Fragment { public MyFragment() { // Required empty public constructor } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // Inflate the layout for this fragment View view = inflater.inflate(R.layout.fragment_my, container, false); // Operate the view, such as setting a monitor, etc. return view; } } Fill and process layout in the oncreateView () method. 5. Manage Fragment After creating Fragment, you need to add it to the Activity and manage it.Use FragmentManager to complete operations such as adding, removing, and replacement of Fragment.The following is a simple example: FragmentManager fragmentManager = getSupportFragmentManager(); FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction(); fragmentTransaction.add(R.id.container, new MyFragment()); fragmentTransaction.commit(); 6. Summary This article discusses the technical principles of Android Support Library Fragment and provides related Java code examples.By using Fragment, a more flexible and modular interface can be achieved. At the same time, through the SUPPORT LIBRARY, this function can be compatible with the old version of the system.For developers who develop Android applications, it is very important to master the technical principles of the Fragment framework.I hope this article will be helpful to readers.