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 && mViewRef.get() != null & mBriefnessorRef != null & 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();
}
}
作者：Android高级开发
链接：https://www.jianshu.com/p/ef99ff863650
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