我写了一个简单的登录demo，用的是传统的Data Binding来实现Android的MVVM架构。对于MVVM我觉得是对MVP架构中P层的一次升华，进一步的解耦，同时view与model又是双向绑定，这种绑定又是支持生命周期检测，不用担心页面销毁了还有回调出现，不需要findViewById也不需要butterknife，不需要拿到具体的View去设置数据绑定监听器等等，全由data binding帮我们完成。

build.gradle(app)

dataBinding{

enabled=true

}

布局

activity_main.xml

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">

name="viewModel"

type="com.leostadyn.stackfarm.mvvmtest.UserViewModel" />

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

tools:context=".MainActivity">

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="@={viewModel.user.status}"

android:id="@+id/txt_user_login_status"/>

android:id="@+id/edit_username"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="@={viewModel.user.userName}"

android:hint="username"/>

android:id="@+id/edit_password"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="@={viewModel.user.password}"

android:hint="password"/>

android:id="@+id/btn_submit"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:textAllCaps="false"

android:onClick="click"

android:text="submit"/>

android:id="@+id/progressBar"

android:visibility="gone"

style="?android:attr/progressBarStyle"

android:layout_width="match_parent"

android:layout_height="wrap_content" />

Model

User.java

import android.databinding.ObservableField;

//User模型

public class User {

//用户名

public ObservableFielduserName=new ObservableField<>();

//密码

public ObservableFieldpassword=new ObservableField<>();

//反馈

public ObservableFieldstatus=new ObservableField<>();

public User() {

}

}

ViewModel

UserViewModel.java

import android.content.Context;

import android.util.Log;

import com.leostadyn.stackfarm.mvvmtest.databinding.ActivityMainBinding;

public class UserViewModel {

private Context context;

private ActivityMainBinding activityMainBinding;

public static final String TAG="KKKKKKK";

public User user;

public UserLocalData data;

public UserViewModel(Context context, ActivityMainBinding activityMainBinding){

this.context=context;

this.activityMainBinding=activityMainBinding;

}

public void init(){

this.user=new User();

this.activityMainBinding.setViewModel(UserViewModel.this);

data=new UserLocalData();

}

//登录

public void login(){

//业务逻辑

Log.e(TAG,"status:"+user.status.get());

Log.e(TAG,"username:"+user.userName.get());

Log.e(TAG,"password:"+user.password.get());

//权限的校验

if (data.findByUser(this.user))

this.user.status.set("success");

else

this.user.status.set("error");

}

}

View

MainActivity.java

public class MainActivity extends AppCompatActivity {

UserViewModel userViewModel;

ProgressBar progressBar;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

// setContentView(R.layout.activity_main);

ActivityMainBinding dataBindingUtil=DataBindingUtil.setContentView(MainActivity.this,R.layout.activity_main);

userViewModel=new UserViewModel(MainActivity.this,dataBindingUtil);

progressBar=findViewById(R.id.progressBar);

}

@Override

protected void onStart() {

super.onStart();

userViewModel.init();

}

public void click(View view) {

progressBar.setVisibility(View.VISIBLE);

new Handler().postDelayed(new Runnable() {

@Override

public void run() {

userViewModel.login();

progressBar.setVisibility(View.GONE);

}

},2000);

}

}

模拟数据处理

public class UserLocalData {

//模拟数据库

String [] userArray={"user1:password1","user2:password2"};

public UserLocalData() {

}

//查找用户

public boolean findByUser(User user){

if(user==null)

throw new NullPointerException("this user object is null");

for (int i = 0; i

String userStr=userArray[i];

String [] userArray=userStr.split(":");

String username=userArray[0];

String password=userArray[1];

if((user.userName.get()).equals(username)&& (user.password.get()).equals(password)){

return true;

}

}

return false;

}

}