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闲话不多少，还是老套路，处理一个登陆的业务。详细的介绍MVVM我就不多说了，网上一大把，毕竟吹水还是我的弱项。

主要实现的功能有两个输入框，一个登陆按钮，两个TextView显示登陆结果。

秀一把我的LoginActivity

@BindLayout(R.layout.activity_login)public class LoginActivity extends BaseActivity<ILoginViewModel, LoginActivityBriefnessor> implements ILoginView {    @Override    protected ILoginViewModel createViewModel(LoginActivityBriefnessor briefnessor) {        return new LoginViewModel(this, briefnessor);    }}

是不是超级简洁，点击事件呢？怎么不见了，再看一看ViewModel

public class LoginViewModel extends BaseViewModel<ILoginView, ILoginModel, LoginActivityBriefnessor> implements ILoginViewModel {

    public LoginViewModel(ILoginView view, LoginActivityBriefnessor briefnessor) {        super(view, briefnessor);    }

    @Override    protected ILoginModel createModel() {        return new LoginModel(this);    }

    @Override    public void onLoginClick(String account, String pswd) {        if (account.length() < 3) {            Toast.makeText(context(), "账号不正确", Toast.LENGTH_SHORT).show();            return;        }        if (pswd.length() < 3) {            Toast.makeText(context(), "密码不正确", Toast.LENGTH_SHORT).show();            return;        }        model.login(account, pswd);    }

    @Override    public void callbackLogin(LoginResult result) {        briefnessor.setResult(result);    }}

ViewModel制作了登陆的数据验证，以及登陆回调的实现，model层完成模拟了登陆。

整个登陆的业务流程Activity并没有参与，在这其中就不得不提一个关键的中间件Briefness，它连接了View层与Model层，帮我们实现了数据绑定，以及事件传递。
我们先看一看布局是如何实现的

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    app:imports="com.hacknife.demo.bean.LoginResult,result"a    app:viewModel="com.hacknife.demo.mvvm.viewmodel.ILoginViewModel"    tools:ignore="MissingPrefix">

    <EditText        android:id="@+id/et_account"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_marginHorizontal="40dp"        android:layout_marginVertical="10dp"        android:hint="账号" />

    <EditText        android:id="@+id/et_pswd"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_marginHorizontal="40dp"        android:layout_marginVertical="10dp"        android:hint="密码" />

    <Button        android:id="@+id/btn_login"        android:layout_width="match_parent"        android:layout_height="40dp"        android:layout_marginHorizontal="40dp"        android:layout_marginVertical="10dp"        android:text="登陆"        app:transfer="onLoginClick($et_account$,$et_pswd$)" />

    <LinearLayout style="@style/text_parent" android:layout_marginHorizontal="40dp">

        <TextView            style="@style/text_childer"            android:text="返回码" />

        <TextView            android:id="@+id/tv_code"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            app:bind="$result.code$" />    </LinearLayout>

    <LinearLayout style="@style/text_parent" android:layout_marginHorizontal="40dp">

        <TextView            style="@style/text_childer"            android:text="结果:" />

        <TextView            android:id="@+id/tv_msg"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            app:bind="$result.msg$" />    </LinearLayout></LinearLayout>

布局中，根布局绑定了ViewModel，以及用于展示登陆结果的数据源。登陆按钮传递单击登陆事件，剩下的两个textView绑定相应的字段。

同时在对应的Activity上绑定相应的布局文件，Briefness就能暂时他强大的功能了，它会自动生成[类名+Briefnessor]的类。

public class LoginActivityBriefnessor implements Briefnessor<LoginActivity> {    public EditText et_account;    public EditText et_pswd;    public Button btn_login;    public TextView tv_code;    public TextView tv_msg;    public LoginResult result;    public ILoginViewModel viewModel;

    @Override    public void bind(final LoginActivity host, Object source) {        if (!Utils.contentViewExist(host)) {            host.setContentView(R.layout.activity_login);        }        et_account = (EditText) host.findViewById(R.id.et_account);        et_pswd = (EditText) host.findViewById(R.id.et_pswd);        btn_login = (Button) host.findViewById(R.id.btn_login);        tv_code = (TextView) host.findViewById(R.id.tv_code);        tv_msg = (TextView) host.findViewById(R.id.tv_msg);        btn_login.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                viewModel.onLoginClick(et_account.getText().toString().trim() , et_pswd.getText().toString().trim());            }        });

    }

    @Override    public void clear() {        this.result = null;        this.viewModel = null;    }

    @Override    public void clearAll() {        this.result = null;        this.viewModel = null;        this.et_account = null;        this.et_pswd = null;        this.btn_login = null;        this.tv_code = null;        this.tv_msg = null;    }    @Override    public void bindViewModel(Object viewModel) {        this.viewModel = (ILoginViewModel) viewModel;    }    public void setResult(LoginResult result) {        if (result == null) return;        this.result = result;        BriefnessInjector.injector(tv_code,result.getCode());        BriefnessInjector.injector(tv_msg,result.getMsg());    }}

该类实现了数据绑定，以及向ViewModel发送消息附带输入框中的值。

Briefness的具体用法，请参考

https://github.com/hacknife/briefness

下面说一说BaseActivity

public abstract class BaseActivity<T extends IBaseViewModel,B extends Briefnessor> extends AppCompatActivity implements IBaseView {    protected T viewModel;    protected B briefnessor;

    @Override    protected void onCreate(@Nullable Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        briefnessor = (B )Briefness.bind(this);        viewModel = createViewModel(briefnessor);        briefnessor.bindViewModel(viewModel);        initView();    }

    protected abstract T createViewModel(B briefnessor);

    @Override    protected void onDestroy() {        super.onDestroy();        if (viewModel != null)            viewModel.dettachView();    }

    protected void initView() {    }

    @Override    public Context applicationContext() {        return getApplication();    }

    @Override    public Activity context() {        return this;    }}

BaseActivity中初始化了Briefness并创建ViewModel绑定到Briefness，并实现了IBaseView

public interface IBaseView {

    Context applicationContext();

    Activity context();}

BaseViewModel继承AbsViewmodel并实现IBaseViewModel，持有Briefnessor，View，Model。

public abstract class BaseViewModel<V extends IBaseView, M extends IBaseModel, B extends Briefnessor> extends AbsViewModel<V> implements IBaseViewModel {

    protected V view;    protected M model;    protected B briefnessor;

    public BaseViewModel(V view, B briefnessor) {        this.attachView(view);        this.attachBriefnessor(briefnessor);        this.view = getView();        this.briefnessor = (B) getBriefnessor();        model = createModel();    }

    protected abstract M createModel();

    @Override    public Context applicationContext() {        return view.applicationContext();    }

    @Override    public Activity context() {        return view.context();    }}

AbsViewModel 的作用主要是释放相应的连接关系。

public abstract class AbsViewModel<T> implements IBaseViewModel{    protected WeakReference<T> mViewRef;    protected WeakReference<Briefnessor> mBriefnessorRef;

    protected void attachView(T view) {        mViewRef = new WeakReference<T>(view);    }

    protected void attachBriefnessor(Briefnessor briefnessor) {        mBriefnessorRef = new WeakReference<Briefnessor>(briefnessor);    }

    protected T getView() {        return mViewRef.get();    }

    protected Briefnessor getBriefnessor() {        return mBriefnessorRef.get();    }

    public boolean isViewAttached() {        return mViewRef != null &amp;&amp; mViewRef.get() != null &amp; mBriefnessorRef != null &amp; mBriefnessorRef.get() != null;    }

    public void dettachView() {        if (mViewRef != null) {            mViewRef.clear();            mViewRef = null;        }        if (mBriefnessorRef != null) {            mBriefnessorRef.clear();            mBriefnessorRef = null;        }    }}

BaseModel 持有ViewModel，并实现了IBaseView。

public abstract class BaseModel<VM extends IBaseViewModel> implements IBaseModel {    protected VM viewModel;

    public BaseModel(VM viewModel) {        this.viewModel = viewModel;    }

    @Override    public Context applicationContext() {        return viewModel.applicationContext();    }

    @Override    public Activity context() {        return viewModel.context();    }}

写的不好，请多多见谅，毕竟小学都没毕业

如果还有什么不明白的，代码直通车

https://github.com/hacknife/Briefness/tree/master/example/src/main/java/com/hacknife/demo/mvvm

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