好用的MVP開發模式，結合ViewModel與LiveData實現

1. 支持標準MVP用法，Activity或者Fragment作爲P
2. 支持ViewModel的簡易用法
3. 支持view複用
4. 支持AndroidX

如何引入

implementation jzw.mvp:jetpmvp:1.0.0

一、簡易模式用法，使用ViewModel和LiveData處理數據

1、創建數據模型model類，構造頁面需要的所有數據，必須繼承IModel接口

   public class StudentModel implements IModel {
           private List<Student> users;
           private String city;

           public List<Student> getUsers() {
               return users;
           }

           public void setUsers(List<Student> users) {
               this.users = users;
           }

           @Override
           public void clearData() {
               //TODO 清理數據

           }
       }

2、創建處理數據的ViewModel類，必須繼承BaseViewModel，負責處理網絡或者本地數據

    public class StudentViewModel extends BaseViewModel<StudentModel> {
        private StudentModel model = new StudentModel();

        public StudentViewModel(Application application) {
            super(application);
        }

        public void initUser() {
            List<Student> list = new ArrayList<>();
            for (int i = 0; i < 10; i++) {
                Student user = new Student("Name" + i, "18", "西安");
                list.add(user);
            }
            model.setUsers(list);
            notifyDataChanged(model);
        }
    }

3、Activity或者Fragment，這裏僅以Activity爲例。

    @BindViewModel(StudentViewModel.class)
    public class StudentActivity extends BaseActivity<StudentModel, StudentViewModel> {
        private RecyclerView recyclerView;
        private MyAdapter mAdapter;

        @Override
        public int getLayoutId() {
            return R.layout.act_student;
        }

        @Override
        public void onInitViews(Bundle savedInstanceState) {
            recyclerView = findViewById(R.id.recyclerView);
            recyclerView.setLayoutManager(new LinearLayoutManager(this));
            mAdapter = new MyAdapter(new ArrayList<Student>());
            recyclerView.setAdapter(mAdapter);
            recyclerView.setItemAnimator(new DefaultItemAnimator());
            recyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.HORIZONTAL));

            viewModel.initUser();
        }

        @Override
        public void onModelChanged(StudentModel model) {
            if (model == null) {
                return;
            }
            mAdapter.setNewData(model.getUsers());
        }
    }

1. 必須添加@BindViewModel註解來指定處理數據的ViewModel類
2. 指定Model與ViewModel的泛型類型
3. 使用viewModel提供的接口處理數據
4. 在onModelChanged回調方法中監聽數據變化，更新UI

二、標準MVP模式用法

1、view創建，只處理UI顯示部分,必須繼承AppViewDelegate或者IViewDelegate接口，view只提供設置UI數據的方法或者獲取控件的方法

    public class UserView extends AppViewDelegate {
        private RecyclerView recyclerView;
        private Button btn;
        private MyAdapter mAdapter;

        @Override
        public int getRootLayoutId() {
            return R.layout.act_word;
        }

        @Override
        public void initViews() {
            super.initViews();
            recyclerView = get(R.id.recyclerView);
            btn = get(R.id.btnInsert);

            recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
            mAdapter = new MyAdapter(new ArrayList<User>());
            recyclerView.setAdapter(mAdapter);
            recyclerView.setItemAnimator(new DefaultItemAnimator());
            recyclerView.addItemDecoration(new DividerItemDecoration(getActivity(), DividerItemDecoration.HORIZONTAL));

        }

        public void setUser(List<User> user) {
            mAdapter.setNewData(user);
        }

        public void onInsertClick(View v) {

        }
     }

2、創建DataBinder類，當model數據變化時負責將model的數據更新到對應的view，需要指定view與model的類型

    public class UserDataBinder implements IDataBinder<UserView, UserModel> {
        @Override
        public void notifyModelChanged(UserView viewDelegate, UserModel data) {
            //真正通知View 更新UI，根據view層提供的方法設置數據
            viewDelegate.setUser(data.getUsers());
        }
    }

3、創建model類，裏面包含View需要的所有數據，同簡易模式一樣，唯一不同的是，這裏需要使用@BindDataBinder註解指定dataBinder，可以是多個

    @BindDataBinder(dataBinder = UserDataBinder.class)
    public class UserModel implements IModel {
        private List<User> users;

        public List<User> getUsers() {
            return users;
        }

        public void setUsers(List<User> users) {
            this.users = users;
        }

        @Override
        public void clearData() {

        }
    }

4、Presenter創建，也就是Activity或者Fragment，必須使用@BindDataBinder註解指定綁定數據的dataBinder

    @BindDataBinder(dataBinder = UserDataBinder.class)
    public class UserListActivity extends ActivityPresenter<UserView> {

        private UserModel model;

        @Override
        public Class<UserView> getViewDelegateClass() {
            return UserView.class;
        }

          /**
            * 所有的初始化工作處理完畢回調
            *
            * @param savedInstanceState
            */
        @Override
        public void onPresenterCreated(Bundle savedInstanceState) {
            model = new UserModel();
            UserViewModel viewModel = ViewModelProviders.of(this).get(UserViewModel.class);
            viewModel.getUsers().observe(this, new Observer<List<User>>() {
                @Override
                public void onChanged(List<User> users) {
                    //設置數據
                    model.setUsers(users);
                    //通知更新UI
                    notifyModelChange(model);
                }
            });
        }
    }

1. 使用@BindDataBinder註解指定綁定數據的dataBinder
2. 指定View泛型的實際類型
3. getViewDelegateClass（）方法返回對應View代理的class
4. 在onPresenterCreated（）回調方法中處理邏輯，我這裏使用了ViewModel來處理的數據

github：https://github.com/jingzhanwu/JJetpackMvpLib