Android--再探MVP模式
1，上一篇我们已经了解了大致的MVP模式，下面再通过这个登录功能的例子 ，我们能过更加容易的掌握MVP模式，再来补充一些闲外话：MVP 是 MVC 的变种，其实是一种升级。要说 MVP 就要说说 MVC，在 MVC 中 Activity 其实是 View层级，但是通常在使用中 Activity即是View也是Controller，并没有将 View层 和 Controller层 进行分离， 耦合度大大提高，非常不利于项目的管理。MVP 把 Activity 中的 UI逻辑 抽象成 View接口，把 业务逻辑 抽象成 Presenter接口，Model类 还是原来的 Model。
2，先来看一下我们这次的简单的布局文件，两个输入框和两个按钮
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.qianmo.mvpdemo.MainActivity">
<EditText
android:id="@+id/editText_user"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:hint="Username"/>
<EditText
android:id="@+id/editText_pass"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignEnd="@+id/editText_user"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignRight="@+id/editText_user"
android:layout_below="@+id/editText_user"
android:hint="Password"/>
<Button
android:id="@+id/button_clean"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_below="@+id/editText_pass"
android:layout_marginLeft="35dp"
android:layout_marginStart="35dp"
android:layout_marginTop="69dp"
android:text="clean"/>
<Button
android:id="@+id/button_login"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/button_clean"
android:layout_alignEnd="@+id/editText_pass"
android:layout_alignRight="@+id/editText_pass"
android:layout_marginEnd="42dp"
android:layout_marginRight="42dp"
android:text="Login"/>
</RelativeLayout>
在创建我们的功能类LoginContract,包含这个登录功能的，view、presenter、model类，这里推荐使用MVPHelper插件，一步搞定
package com.qianmo.mvpdemo.contract;
/**
* Created by wangjitao on 2016/10/31 0031.
* 用于实现登录功能的实现类
*/
public class LoginContract {
public interface View {
public void doClean();
public void loginResult(boolean isSuccess, String messing);
}
public interface Presenter {
public void clean();
public void doLogin(String username, String password);
}
public interface Model {
}
}
model实现类
package com.qianmo.mvpdemo.model;
import com.qianmo.mvpdemo.contract.LoginContract;
/**
* Created by MVPHelper on 2016/10/31
*/
public class LoginModelImpl implements LoginContract.Model {
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;
}
}
persenter的实现类
package com.qianmo.mvpdemo.presenter;
import com.qianmo.mvpdemo.MainActivity;
import com.qianmo.mvpdemo.contract.LoginContract;
/**
* Created by MVPHelper on 2016/10/31
*/
public class LoginPresenterImpl implements LoginContract.Presenter {
private MainActivity mainActivity;
public LoginPresenterImpl(MainActivity mainActivity) {
this.mainActivity = mainActivity;
}
@Override
public void clean() {
mainActivity.doClean();
}
@Override
public void doLogin(String username, String password) {
if ("wangjitao".equals(username) && "123".equals(password)) {
mainActivity.loginResult(true, "user:" + username + ",pass:" + password);
}else {
mainActivity.loginResult(false, "user:" + username + ",pass:" + password);
}
}
}
最后是我们的UI，也就是我们的Activity
package com.qianmo.mvpdemo;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import com.qianmo.mvpdemo.contract.LoginContract;
import com.qianmo.mvpdemo.presenter.LoginPresenterImpl;
public class MainActivity extends AppCompatActivity implements LoginContract.View, View.OnClickListener {
private EditText et_username;
private EditText et_password;
private Button btn_clean;
private Button btn_login;
private LoginPresenterImpl mLoginPresenter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
et_username = (EditText) findViewById(R.id.editText_user);
et_password = (EditText) findViewById(R.id.editText_pass);
btn_clean = (Button) findViewById(R.id.button_clean);
btn_login = (Button) findViewById(R.id.button_login);
mLoginPresenter = new LoginPresenterImpl(this);
btn_login.setOnClickListener(this);
btn_clean.setOnClickListener(this);
}
@Override
public void doClean() {
et_username.setText("");
et_password.setText("");
}
@Override
public void loginResult(boolean isSuccess, String messing) {
if (isSuccess) {
Toast.makeText(MainActivity.this, "登陆成功：" + messing, Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(MainActivity.this, "登陆失败", Toast.LENGTH_SHORT).show();
}
}
@Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.button_clean:
mLoginPresenter.clean();
break;
case R.id.button_login:
mLoginPresenter.doLogin(et_username.getText().toString(), et_password.getText().toString());
break;
}
}
}
ok，这样的话 感觉一会儿就写出MVP的小demo了
