Android MVP模式的简单实现

MVP代码中通常包含四个元素:

View:负责绘制UI元素、与用户进行交互(在Android中体现为Activity);

View interface:需要View实现的接口，View通过View interface与Presenter进行交互，降低耦合，方便进行单元测试;

Model:负责存储、检索、操纵数据(有时也实现一个Model interface用来降低耦合);

Presenter:作为View与Model交互的中间纽带，处理与用户交互的负责逻辑。



从图中可以看出,View已经和Model没有什么关系了,真正的逻辑在presenter中进行处理,使View和Model只依赖与Presenter,结构更加清晰

一个简单的Demo

先请求网络接口,此时View显示Loading状态,等待接口返回后,View显示真正的数据.

Loading状态



显示数据的状态

代码结构

View层

提供一个通用的View接口

/**
* Created by shixi_tianrui1 on 16-12-3
* View接口需设置Presenter
*/
public interface BaseView<T extends BasePresenter> {
void setPresenter(T presenter);
}

当前Activity需实现的View接口

/**
* Created by shixi_tianrui1 on 16-12-3.
* View层的显示逻辑
*/

public interface MainView<T> extends BaseView {
void showWeatherInfo(T data);

void showProgress();

void stopProgress();

void showError();
}

Model层

这里的Model层只负责准备数据,其他用

Presenter

进行处理

/**
* Created by shixi_tianrui1 on 16-12-3.
* 从网络中取{@link WeatherBean},再回调给Presenter
*/

public class WeatherModel {
public void getWeatherData(final MyCallBack myCallBack) {
// 使用Retrofit请求数据,通过Callback对象进行回调
Call<WeatherBean> call = MyApplication.sService.getWeather("101010100");
call.enqueue(new Callback<WeatherBean>() {
@Override
public void onResponse(Response<WeatherBean> response) {
myCallBack.success(response);
}

@Override
public void onFailure(Throwable t) {
myCallBack.failure(t);
}
});
}

// 网络接口的回调
public interface MyCallBack {
void success(Response<WeatherBean> response);

void failure(Throwable throwable);
}
}

Bean对象

/**
* Created by shixi_tianrui1 on 16-12-3.
* 网络接口返回的Bean对象
*/

public class WeatherBean {

private WeatherinfoBean weatherinfo;

public WeatherinfoBean getWeatherinfo() {
return weatherinfo;
}

public void setWeatherinfo(WeatherinfoBean weatherinfo) {
this.weatherinfo = weatherinfo;
}

@Override
public String toString() {
return "WeatherBean{" +
"weatherinfo=" + weatherinfo +
'}';
}

public static class WeatherinfoBean {
private String city;
private String cityid;
private String temp;
private String WD;
private String WS;
private String SD;
private String WSE;
private String time;
private String isRadar;
private String Radar;
private String njd;
private String qy;

public String getCity() {
return city;
}

public void setCity(String city) {
this.city = city;
}

public String getCityid() {
return cityid;
}

public void setCityid(String cityid) {
this.cityid = cityid;
}

public String getTemp() {
return temp;
}

public void setTemp(String temp) {
this.temp = temp;
}

public String getWD() {
return WD;
}

public void setWD(String WD) {
this.WD = WD;
}

public String getWS() {
return WS;
}

public void setWS(String WS) {
this.WS = WS;
}

public String getSD() {
return SD;
}

public void setSD(String SD) {
this.SD = SD;
}

public String getWSE() {
return WSE;
}

public void setWSE(String WSE) {
this.WSE = WSE;
}

public String getTime() {
return time;
}

public void setTime(String time) {
this.time = time;
}

public String getIsRadar() {
return isRadar;
}

public void setIsRadar(String isRadar) {
this.isRadar = isRadar;
}

public String getRadar() {
return Radar;
}

public void setRadar(String Radar) {
this.Radar = Radar;
}

public String getNjd() {
return njd;
}

public void setNjd(String njd) {
this.njd = njd;
}

public String getQy() {
return qy;
}

public void setQy(String qy) {
this.qy = qy;
}

@Override
public String toString() {
return "WeatherinfoBean{" +
"city='" + city + '\'' +
", cityid='" + cityid + '\'' +
", temp='" + temp + '\'' +
", WD='" + WD + '\'' +
", WS='" + WS + '\'' +
", SD='" + SD + '\'' +
", WSE='" + WSE + '\'' +
", time='" + time + '\'' +
", isRadar='" + isRadar + '\'' +
", Radar='" + Radar + '\'' +
", njd='" + njd + '\'' +
", qy='" + qy + '\'' +
'}';
}
}
}

Presenter层

同样,提供基础接口

/**
* Created by shixi_tianrui1 on 16-12-3.
* Presenter基础操作
*/

public interface BasePresenter {
void start();
}

具体业务逻辑的Presenter实现

这里持有的view和model的引用.是ui和数据的桥梁

/**
* Created by shixi_tianrui1 on 16-12-3.
* 对View和Model进行操作
*/

public class WeatherPresenter implements BasePresenter {

private Handler mHandler = new Handler();
private MainView<WeatherBean> mView;
private WeatherModel mModel;

public WeatherPresenter(MainView<WeatherBean> view) {
this.mView = view;
mModel = new WeatherModel();
}

private void getHttpData() {
mModel.getWeatherData(new WeatherModel.MyCallBack() {
@Override
public void success(Response<WeatherBean> response) {
mView.stopProgress();
mView.showWeatherInfo(response.body());
}

@Override
public void failure(Throwable throwable) {
mView.stopProgress();
mView.showError();
}
});
}

@Override
public void start() {
mView.showProgress();
// 模拟网络延时
mHandler.postDelayed(new Runnable() {
@Override
public void run() {
getHttpData();
}
}, 10000);

}
}

Activity中的只需实现View接口即可,并且将自身设置给Presenter

可以看出,实现的都是View接口的方法

/**
* Activity是MainView的具体实现
*/
public class MainActivity extends AppCompatActivity implements MainView<WeatherBean> {

private WeatherPresenter mPreserter = new WeatherPresenter(this);

private TextView mTvText;
private View mLoading;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTvText = (TextView) findViewById(R.id.id_tv_text);
mLoading = findViewById(R.id.id_fl_loading);
// Presenter进行处理
mPreserter.start();
}

@Override
public void showWeatherInfo(WeatherBean data) {
mTvText.setText(data.toString());
}

@Override
public void showProgress() {
mLoading.setVisibility(View.VISIBLE);
}

@Override
public void stopProgress() {
mLoading.setVisibility(View.GONE);
}

@Override
public void showError() {
mTvText.setText("network error!");
}

@Override
public void setPresenter(BasePresenter presenter) {
mPreserter = (WeatherPresenter) presenter;
}
}

Retroft请求类

Retroft初始化

public class MyApplication extends Application {
public static ApiService sService;

@Override
public void onCreate() {
super.onCreate();
// 初始化Retrofit
File httpCacheDirectory = new File(getExternalCacheDir(), "responses");
Cache cache = new Cache(httpCacheDirectory, 20 * 1024 * 1024);
OkHttpClient client = new OkHttpClient.Builder()
.cache(cache).build();
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("http://www.weather.com.cn/")
.client(client)
.addConverterFactory(GsonConverterFactory.create())
.build();

sService = retrofit.create(ApiService.class);
}
}

Api请求

public interface ApiService {

@GET("adat/sk/{cityId}.html")
Call<WeatherBean> getWeather(@Path("cityId") String cityId);

}