一,MVP是一种高度解耦的架构模式:
1.M层:------->model层:主要处理业务逻辑
2.V层---------->View层:主要是视图层(activity , fragment ,dialog)
3.P层---------->present层:桥梁作用,串接M层和V层
本文参考:https://blog.****.net/u011418943/article/details/69840880
加上自己的一些理解,希望批评指正,以下是demo的流程
---------------------1.目录结构-----------------------
------------------------2.效果图-----------------------------
布局很简单就不贴了:主要业务就是保存user信息到数据库(litepal),输入姓名直接查找信息
------------------------------3.引入litepal数据库---------------------------------
1.依赖
dependencies {
compile 'org.litepal.android:core:1.5.0'
}
2.在AndroidManifest文件中注册
<application>
android:name="org.litepal.LitePalApplication"
</application>
3.创建数据库表
1.在main文件下创建一个assets文件夹,
2.在assets中创建litepal.xml文件
3.建数据库
<?xml version="1.0" encoding="utf-8"?>
<litepal>
<dbname value="user"/>
<version value="1"/>
<list>
<mapping class= "com.gz.test111.bean.User"/>
</list>
</litepal>----------------------4.代码开发--------------------------------
思路:view层只是为了获取到我们输入的姓名和密码,所以只要提供两个接口就好了;;model我们要处理如何去拿到数据库的数据和将数据保存到数据库就好了,最后用present层把以上两个串联起来
1.准备一个User类,作为javabean
//一定要继承DataSupport
public class User extends DataSupport {
private String userName;
private String passWord;
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassWord() {
return passWord;
}
public void setPassWord(String passWord) {
this.passWord = passWord;
}
@Override
public String toString() {
return "User{" +
"userName='" + userName + '\'' +
", passWord='" + passWord + '\'' +
'}';
}
}2.View层我们只管UI和用户输入的数据
2.1先定义接口类
public interface IUserView{
void setUserName(String name);
void setUserPassword(String password);
void error(String errorMessage);
}2.2在activity中实现以上三个方法
public class LoginActivity extends AppCompatActivity implements IUserView, View.OnClickListener {
/**
* USERNAME
*/
private EditText mEtUsername;
/**
* PASSWORD
*/
private EditText mEtPassword;
/**
* save
*/
private Button mBtnLogin;
/**
* SEARCH
*/
private EditText mEtSearch;
/**
* search
*/
private Button mBtnSearch;
UserPresenter userPresenter;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
initView();
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btn_login:
save();
break;
case R.id.btn_search:
read(mEtSearch.getText().toString());
break;
}
}
private void read(String name) {
userPresenter.readData(name);//P层方法
}
private void save() {
User user = new User();
user.setUserName(mEtUsername.getText().toString());
user.setPassWord(mEtPassword.getText().toString());
userPresenter.saveData(user);//P层的方法
}
@Override
public void setUserName(String name) {
mEtUsername.setText(name);
}
@Override
public void setUserPassword(String password) {
mEtPassword.setText(password);
}
@Override
public void error(String errorMessage) {
Toast.makeText(this, errorMessage, Toast.LENGTH_SHORT).show();
}
private void initView() {
mEtUsername = (EditText) findViewById(R.id.et_username);
mEtPassword = (EditText) findViewById(R.id.et_password);
mBtnLogin = (Button) findViewById(R.id.btn_login);
mBtnLogin.setOnClickListener(this);
mEtSearch = (EditText) findViewById(R.id.et_search);
mBtnSearch = (Button) findViewById(R.id.btn_search);
mBtnSearch.setOnClickListener(this);
userPresenter = new UserPresenter(this);//后面的P层
}
}
3.model层我们处理业务逻辑,就是将数据保存和读取数据库的数据
3.1定义接口
public interface IUserModel {
void saveUserData(User user);
User readUserData(String name);
}3.2实现接口
public class UserModel implements IUserModel {
public UserModel(){
}
@Override
public void saveUserData(User user) {
user.save();
Log.d("user", "saveUserData: " + user);
}
@Override
public User readUserData(String name) {
Log.d("tag", "readUserData: " + name);
List<User> userList = DataSupport.where("userName = ?" , name).find(User.class);
if (userList.size() > 0){
return userList.get(0);
}
return null;
}
}
4.Model层和View层都在处理自己的事情了,现在毫无关系,所以需要P层将他们链接起来,,,要让用户输入的数据点击按钮可以保存到数据库,点击查询可以从数据库拿到数据
public class UserPresenter {
private IUserView iUserView;
private IUserModel iUserModel;
//让P层同时持有V层和M层对象
public UserPresenter (IUserView iUserView){
this.iUserView = iUserView;
iUserModel = new UserModel();//多态
}
public void saveData(User user){
Log.d("tag", "saveData: " + user);
iUserModel.saveUserData(user);//直接把数据存到M层接口中,此接口的实现类也就含有了当前的数据
}
public void readData(String name){
User user = iUserModel.readUserData(name);//直接把数据存到M层接口中,此接口的实现类也就含有了当前的数据
if (user != null){
iUserView.setUserName(user.getUserName());//V层接口将数据的数据设置给当前name的edittext
iUserView.setUserPassword(user.getPassWord());//V层接口将数据的数据设置给当前pwd的edittext
}else {
iUserView.error("没有找到");
}
}
}
以上就完成了MVP的简单demo