Android MVP架構搭建
阿新 • • 發佈：2018-12-16
一、 MVP概念
M ： Model （資料層） 用於載入資料，
V：View（檢視層） 載入介面及檢視
P：Presenter（互動層） 進行邏輯操作
二、MVP的優點
1.Model層與View層完全分離（ 不用擔心改需求了）
2.分工更加明確，邏輯更加清晰，易於維護程式碼
3.便於單元測試
其他……
三、例項（簡單的登入）
1.新建專案，建立如下的包及專案結構：
2.Bean包中包含兩個類，分別是User 和 LoginResult，程式碼如下：
public class LoginResult {
public boolean success;
public boolean nameErr;
public boolean passwordErr;
public String errMsg;
public LoginResult(boolean success, boolean nameErr, boolean passwordErr, String errMsg) {
this.success = success;
this.nameErr = nameErr;
this.passwordErr = passwordErr;
this.errMsg = errMsg;
}
} public class User {
public User(String username, String password) {
this.username = username;
this.password = password;
}
public String username;
public String password;
}
3.Model層中，建立IUserModel介面，UserModel繼承該介面，並實現userLogin方法。
public interface IUserModel {
void Login(User user , UserLoginCompleteListener listener);
interface UserLoginCompleteListener{
void onUserLoginCompleted(LoginResult result);
}
}
import android.os.Handler;
import android.shinetech.com.finalmvpdemo.Bean.LoginResult;
import android.shinetech.com.finalmvpdemo.Bean.User;
import android.text.TextUtils;
public class UserModel implements IUserModel{
@Override
public void Login( final User user, final UserLoginCompleteListener listener) {
Handler handler = new Handler() ;
handler.post(new Runnable() {
@Override
public void run() {
LoginResult result = new LoginResult(true, false ,false,"");
if(TextUtils.isEmpty(user.username) ){
result.success = false;
result.nameErr = true;
result.errMsg = "Username is empty";
}
if(TextUtils.isEmpty(user.password) ){
result.success = false;
result.passwordErr = true;
result.errMsg = "Password is empty";
}
listener.onUserLoginCompleted(result);
}
});
}
}4.Presenter層建立抽象類BasePresenter，並實現UserLoginPresenter.其中BasePresenter可以是所有Presenter的父類，該類中用WeakReference（弱引用）來減少記憶體洩漏的風險。
import java.lang.ref.WeakReference;
public class BasePresenter<V> {
WeakReference<V> weakReference;
public void detachView(){
if(weakReference != null){
weakReference.clear();
}
}
public void attachView(V view){
weakReference = new WeakReference<V>((V)view);
}
public V getView(){
return weakReference.get();
}
}
UserLoginPresenter類繼承自BasePresenter，並實現了ILoginView的介面，該介面包含了介面顯示的一些方法，如showProgressBar等。
import android.shinetech.com.finalmvpdemo.Bean.LoginResult;
import android.shinetech.com.finalmvpdemo.Bean.User;
import android.shinetech.com.finalmvpdemo.LoginActivity;
import android.shinetech.com.finalmvpdemo.Model.IUserModel;
import android.shinetech.com.finalmvpdemo.Model.UserModel;
import android.shinetech.com.finalmvpdemo.View.ILoginView;
import android.view.View;
public class UserLoginPresenter extends BasePresenter<LoginActivity> implements ILoginView {
IUserModel model = new UserModel();
public void login(User user) {
showProgress(View.VISIBLE);
model.Login(user, new IUserModel.UserLoginCompleteListener() {
@Override
public void onUserLoginCompleted(LoginResult result) {
if (result.success) {
showSuccess();
} else if (result.nameErr) {
showNameError();
showError(result.errMsg);
} else if (result.passwordErr) {
showPasswordError();
showError(result.errMsg);
}
showProgress(View.INVISIBLE);
}
});
}
@Override
public void showNameError() {
getView().showNameError();
}
@Override
public void showPasswordError() {
getView().showPasswordError();
}
@Override
public void showProgress(int visiblity) {
getView().showProgress(visiblity);
}
@Override
public void showSuccess() {
getView().showSuccess();
}
@Override
public void showError(String errMsg) {
getView().showError(errMsg);
}
}
5.在View層，建立了BaseActivity，所有的Activity都可以繼承自此類，減少重複程式碼，並用泛型將presenter例項化推層到具體的介面層。
import android.os.Bundle;
import android.shinetech.com.finalmvpdemo.Presenter.BasePresenter;
import android.support.v7.app.AppCompatActivity;
public abstract class BaseActivity<V, P extends BasePresenter> extends AppCompatActivity {
protected BasePresenter p;
protected abstract P createPresenter();
@Override
protected void onCreate( Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
p = createPresenter();
p.attachView((V)this);
}
}
public interface ILoginView {
void showNameError();
void showPasswordError();
void showProgress(int visiblity);
void showSuccess();
void showError(String errMsg);
}
6.LoginActivity 此處為專案入口（通常是MainActivity）,展示介面，並處理觸發的事件。
import android.os.Bundle;
import android.shinetech.com.finalmvpdemo.Bean.User;
import android.shinetech.com.finalmvpdemo.Presenter.UserLoginPresenter;
import android.shinetech.com.finalmvpdemo.View.BaseActivity;
import android.shinetech.com.finalmvpdemo.View.ILoginView;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.Toast;
public class LoginActivity extends BaseActivity<LoginActivity, UserLoginPresenter > implements ILoginView {
private ImageView err_username;
private ImageView err_password;
private Button btn_login;
private EditText txt_username;
private EditText txt_password;
private ProgressBar progressBar;
@Override
protected UserLoginPresenter createPresenter() {
return new UserLoginPresenter();
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
err_username = findViewById(R.id.err_username);
err_password = findViewById(R.id.err_password);
txt_username = findViewById(R.id.txtUsername);
txt_password = findViewById(R.id.txtPassword);
btn_login = findViewById(R.id.btn_login);
progressBar = findViewById(R.id.progressBar);
btn_login.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
User user = new User(txt_username.getText().toString(), txt_password.getText().toString());
((UserLoginPresenter)p).login(user);
}
});
}
@Override
public void showNameError() {
err_username.setVisibility(View.VISIBLE);
}
@Override
public void showPasswordError() {
err_password.setVisibility(View.VISIBLE);
}
@Override
public void showProgress(int visiblity) {
progressBar.setVisibility(visiblity);
}
@Override
public void showSuccess() {
err_username.setVisibility(View.INVISIBLE);
err_password.setVisibility(View.INVISIBLE);
progressBar.setVisibility(View.INVISIBLE);
Toast.makeText(this, "Login success.",Toast.LENGTH_LONG).show();
}
@Override
public void showError(String errMsg) {
Toast.makeText(this, errMsg,Toast.LENGTH_LONG).show();
}
}
7.最後貼上activity_login.xml的layout程式碼 ，如下：
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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"
tools:context=".LoginActivity">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Login"
android:textAllCaps="false"
android:textSize="40dp"
android:layout_margin="10dp"
android:textAlignment="center"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
android:id="@+id/lblTitle"
/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintTop_toBottomOf="@+id/lblTitle"
android:id="@+id/line_username"
>
<TextView
android:layout_weight="1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Username:"
android:textAlignment="center"
/>
<EditText
android:layout_weight="4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/txtUsername"
/>
<ImageView
android:layout_width="20dp"
android:layout_height="20dp"
android:src="@mipmap/x"
android:visibility="invisible"
android:layout_gravity="center"
android:id="@+id/err_username"
/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintTop_toBottomOf="@+id/line_username"
android:id="@+id/line_password"
>
<TextView
android:layout_weight="1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Password:"
android:textAlignment="center"
/>
<EditText
android:layout_weight="4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/txtPassword"
/>
<ImageView
android:layout_width="20dp"
android:layout_height="20dp"
android:src="@mipmap/x"
android:visibility="invisible"
android:layout_gravity="center"
android:id="@+id/err_password"
/>
</LinearLayout>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintTop_toBottomOf="@+id/line_password"
android:textAlignment="center"
>
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/progressBar"
android:layout_toLeftOf="@+id/btn_login"
android:visibility="gone"
/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/btn_login"
android:textAlignment="center"
android:text="Login"
android:layout_centerHorizontal="true"
/>
</RelativeLayout>
</android.support.constraint.ConstraintLayout>
