1.MVP介紹

在Android項目中，Activity和Fragment占據了大部分的開發工作。如果有一種設計模式（或者說代碼結構）專門是為優化Activity和Fragment的代碼而產生的，你說這種模式重要不？這就是MVP設計模式。

按照MVC的分層，Activity和Fragment（后面只說Activity）應該屬于View層，用于展示UI界面，以及接收用戶的輸入，此外還要承擔一些生命周期的工作。Activity是在Android開發中充當非常重要的角色，特別是TA的生命周期的功能，所以開發的時候我們經常把一些業務邏輯直接寫在Activity里面，這非常直觀方便，代價就是Activity會越來越臃腫，超過1000行代碼是常有的事，而且如果是一些可以通用的業務邏輯（比如用戶登錄），寫在具體的Activity里就意味著這個邏輯不能復用了。如果有進行代碼重構經驗的人，看到1000+行的類肯定會有所顧慮。因此，Activity不僅承擔了View的角色，還承擔了一部分的Controller角色，這樣一來V和C就耦合在一起了，雖然這樣寫方便，但是如果業務調整的話，要維護起來就難了，而且在一個臃腫的Activity類查找業務邏輯的代碼也會非常蛋疼，所以看起來有必要在Activity中，把View和Controller抽離開來，而這就是MVP模式的工作了。

MVP模式的核心思想：

MVP把Activity中的UI邏輯抽象成View接口，把業務邏輯抽象成Presenter接口，Model類還是原來的Model。

這就是MVP模式，現在這樣的話，Activity的工作的簡單了，只用來響應生命周期，其他工作都丟到Presenter中去完成。從上圖可以看出，Presenter是Model和View之間的橋梁，為了讓結構變得更加簡單，View并不能直接對Model進行操作，這也是MVP與MVC最大的不同之處。

2.與mvc區別

3.Rxjava+Retrofit+Mvp的在項目中得使用

1）項目結構如下

2）添加依賴

dependencies {compile fileTree(dir: 'libs', include: ['*.jar'])androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {exclude group: 'com.android.support', module: 'support-annotations' }) compile 'com.android.support:appcompat-v7:25.3.0'compile 'io.reactivex:rxandroid:1.2.0'compile 'com.squareup.retrofit2:adapter-rxjava:2.1.0'compile 'com.squareup.retrofit2:converter-gson:2.1.0'compile 'com.squareup.retrofit2:retrofit:2.1.0' testCompile 'junit:junit:4.12' }

3）api包內容

public interface APIManagerService {@GET("/weather/index")Observable<WeatherData> getWeatherData(@Query("format") String format, @Query("cityname") String cityname, @Query("key") String key) ; }
public class APIManager {private static final String ENDPOINT = "http://v.juhe.cn"; private static final Retrofit sRetrofit = new Retrofit .Builder().baseUrl(ENDPOINT).addConverterFactory(GsonConverterFactory.create()).addCallAdapterFactory(RxJavaCallAdapterFactory.create()) // 使用RxJava作為回調適配器 .build(); private static final APIManagerService apiManager = sRetrofit.create(APIManagerService.class); /** * 獲取天氣數據 * @param city * @return */ public static Observable<WeatherData> getWeatherData(String format, String city) {return apiManager.getWeatherData(format,city,"ad1d20bebafe0668502c8eea5ddd0333"); }}

4）創建bean對象

public class WeatherData { private String resultcode; private String reason; private ResultEntity result; private int error_code; public void setResultcode(String resultcode) {this.resultcode = resultcode; }public void setReason(String reason) {this.reason = reason; }public void setResult(ResultEntity result) {this.result = result; }public void setError_code(int error_code) {this.error_code = error_code; }public String getResultcode() {return resultcode; }public String getReason() {return reason; }public ResultEntity getResult() {return result; }public int getError_code() {return error_code; }public static class ResultEntity { private SkEntity sk; private TodayEntity today; private List<FutureEntity> future; public void setSk(SkEntity sk) {this.sk = sk; }public void setToday(TodayEntity today) {this.today = today; }public void setFuture(List<FutureEntity> future) {this.future = future; }public SkEntity getSk() {return sk; }public TodayEntity getToday() {return today; }public List<FutureEntity> getFuture() {return future; }public static class SkEntity {private String temp; private String wind_direction; private String wind_strength; private String humidity; private String time; public void setTemp(String temp) {this.temp = temp; }public void setWind_direction(String wind_direction) {this.wind_direction = wind_direction; }public void setWind_strength(String wind_strength) {this.wind_strength = wind_strength; }public void setHumidity(String humidity) {this.humidity = humidity; }public void setTime(String time) {this.time = time; }public String getTemp() {return temp; }public String getWind_direction() {return wind_direction; }public String getWind_strength() {return wind_strength; }public String getHumidity() {return humidity; }public String getTime() {return time; }@Override public String toString() {return "SkEntity{" +"temp='" + temp + '\'' +", wind_direction='" + wind_direction + '\'' +", wind_strength='" + wind_strength + '\'' +", humidity='" + humidity + '\'' +", time='" + time + '\'' +'}'; }}public static class TodayEntity {@Override public String toString() {return "TodayEntity{" +"temperature='" + temperature + '\'' +", weather='" + weather + '\'' +", weather_id=" + weather_id +", wind='" + wind + '\'' +", week='" + week + '\'' +", city='" + city + '\'' +", date_y='" + date_y + '\'' +", dressing_index='" + dressing_index + '\'' +", dressing_advice='" + dressing_advice + '\'' +", uv_index='" + uv_index + '\'' +", comfort_index='" + comfort_index + '\'' +", wash_index='" + wash_index + '\'' +", travel_index='" + travel_index + '\'' +", exercise_index='" + exercise_index + '\'' +", drying_index='" + drying_index + '\'' +'}'; }private String temperature; private String weather; private WeatherIdEntity weather_id; private String wind; private String week; private String city; private String date_y; private String dressing_index; private String dressing_advice; private String uv_index; private String comfort_index; private String wash_index; private String travel_index; private String exercise_index; private String drying_index; public void setTemperature(String temperature) {this.temperature = temperature; }public void setWeather(String weather) {this.weather = weather; }public void setWeather_id(WeatherIdEntity weather_id) {this.weather_id = weather_id; }public void setWind(String wind) {this.wind = wind; }public void setWeek(String week) {this.week = week; }public void setCity(String city) {this.city = city; }public void setDate_y(String date_y) {this.date_y = date_y; }public void setDressing_index(String dressing_index) {this.dressing_index = dressing_index; }public void setDressing_advice(String dressing_advice) {this.dressing_advice = dressing_advice; }public void setUv_index(String uv_index) {this.uv_index = uv_index; }public void setComfort_index(String comfort_index) {this.comfort_index = comfort_index; }public void setWash_index(String wash_index) {this.wash_index = wash_index; }public void setTravel_index(String travel_index) {this.travel_index = travel_index; }public void setExercise_index(String exercise_index) {this.exercise_index = exercise_index; }public void setDrying_index(String drying_index) {this.drying_index = drying_index; }public String getTemperature() {return temperature; }public String getWeather() {return weather; }public WeatherIdEntity getWeather_id() {return weather_id; }public String getWind() {return wind; }public String getWeek() {return week; }public String getCity() {return city; }public String getDate_y() {return date_y; }public String getDressing_index() {return dressing_index; }public String getDressing_advice() {return dressing_advice; }public String getUv_index() {return uv_index; }public String getComfort_index() {return comfort_index; }public String getWash_index() {return wash_index; }public String getTravel_index() {return travel_index; }public String getExercise_index() {return exercise_index; }public String getDrying_index() {return drying_index; }public static class WeatherIdEntity {private String fa; private String fb; public void setFa(String fa) {this.fa = fa; }public void setFb(String fb) {this.fb = fb; }public String getFa() {return fa; }public String getFb() {return fb; }}}public static class FutureEntity {private String temperature; private String weather; /** * fa : 01 * fb : 01 */ private WeatherIdEntity weather_id; private String wind; private String week; private String date; public void setTemperature(String temperature) {this.temperature = temperature; }public void setWeather(String weather) {this.weather = weather; }public void setWeather_id(WeatherIdEntity weather_id) {this.weather_id = weather_id; }public void setWind(String wind) {this.wind = wind; }public void setWeek(String week) {this.week = week; }public void setDate(String date) {this.date = date; }public String getTemperature() {return temperature; }public String getWeather() {return weather; }public WeatherIdEntity getWeather_id() {return weather_id; }public String getWind() {return wind; }public String getWeek() {return week; }public String getDate() {return date; }public static class WeatherIdEntity {private String fa; private String fb; public void setFa(String fa) {this.fa = fa; }public void setFb(String fb) {this.fb = fb; }public String getFa() {return fa; }public String getFb() {return fb; }@Override public String toString() {return "WeatherIdEntity{" +"fa='" + fa + '\'' +", fb='" + fb + '\'' +'}'; }}@Override public String toString() {return "FutureEntity{" +"temperature='" + temperature + '\'' +", weather='" + weather + '\'' +", weather_id=" + weather_id +", wind='" + wind + '\'' +", week='" + week + '\'' +", date='" + date + '\'' +'}'; }}@Override public String toString() {return "ResultEntity{" +"sk=" + sk +", today=" + today +", future=" + future +'}'; }}@Override public String toString() {return "WeatherData{" +"resultcode='" + resultcode + '\'' +", reason='" + reason + '\'' +", result=" + result +", error_code=" + error_code +'}'; }

5）model層

public interface WeatherModel {Subscription getWeatherData(String format, String city); } public class WeatherModelImp implements WeatherModel {private WeatherOnListener mWeatherOnListener; public WeatherModelImp(WeatherOnListener mWeatherOnListener) {this.mWeatherOnListener = mWeatherOnListener; }@Override public Subscription getWeatherData(String format, String city) {//com.example.admin.rxretrofitmvp.api.APIManager Observable<WeatherData> request = com.example.admin.rxretrofitmvp.api.APIManager.getWeatherData(format, city).cache(); Subscription sub = request.subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe(new Action1<WeatherData>() {@Override public void call(WeatherData weatherData) {mWeatherOnListener.onSuccess(weatherData); }}, new Action1<Throwable>() {@Override public void call(Throwable throwable) {mWeatherOnListener.onFailure(throwable); }}); return sub; }

6）Present層

public class BasePesenter {protected CompositeSubscription mCompositeSubscription; //RXjava取消注冊，以避免內存泄露 public void onUnsubscribe() {if (mCompositeSubscription != null && mCompositeSubscription.hasSubscriptions()) {mCompositeSubscription.unsubscribe(); }}//RXjava注冊 public void addSubscription(Subscription subscriber) {if (mCompositeSubscription == null) {mCompositeSubscription = new CompositeSubscription(); }mCompositeSubscription.add(subscriber); } }
public abstract class WeatherPresenter extends BasePesenter {public abstract void getWeatherData(String format, String city); }
public class WeatherPresenterImp extends WeatherPresenter implements WeatherOnListener{/** * WeatherModel和WeatherView都是通過接口來實現，這就Java設計原則中依賴倒置原則使用 */ private WeatherModel mWeatherModel; private WeatherView mWeatherView; public WeatherPresenterImp( WeatherView mWeatherView) {this.mWeatherModel = new WeatherModelImp(this); this.mWeatherView = mWeatherView; }@Override public void getWeatherData(String format, String city) {mWeatherView.showProgress(); addSubscription(mWeatherModel.getWeatherData(format,city)); }@Override public void onSuccess(WeatherData s) {mWeatherView.loadWeather(s); mWeatherView.hideProgress(); Log.d("-------", "onSuccess() called with: " + "s = [" + s.toString() + "]"); }@Override public void onFailure(Throwable e) {mWeatherView.hideProgress(); Log.d("-------", "onFailure" + e.getMessage()); } }

7）view層

public interface WeatherView {void showProgress(); void hideProgress(); void loadWeather(WeatherData weatherData); }

8）監聽器

public interface WeatherOnListener {void onSuccess(WeatherData s); void onFailure(Throwable e); }

9）LodingHelper

public class LoadingUIHelper {private static Dialog dialog; public static void showDialogForLoading(final Context context, String tipContext){final AlertDialog.Builder builder = new AlertDialog.Builder(context); dialog = builder.create(); builder.setTitle(""); builder.setMessage(tipContext); builder.setIcon(R.mipmap.ic_launcher); builder.setNegativeButton("取消",new DialogInterface.OnClickListener(){@Override public void onClick(DialogInterface dialogInterface, int i) {dialog.dismiss(); }}); builder.setPositiveButton("確定",new DialogInterface.OnClickListener(){@Override public void onClick(DialogInterface dialogInterface, int i) {}}); builder.show(); }public static void hideDialogForLoading(){if(dialog != null){dialog.dismiss(); }} }

10）在Activity中處理

public class MainActivity extends AppCompatActivity implements WeatherView{private WeatherPresenterImp mWeatherPresenter; private TextView textView1; private TextView textView2; private TextView textView3; private TextView textView4; private TextView textView5; private TextView textView6; private TextView textView7; private TextView textView8; private TextView textView9; @Override protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mWeatherPresenter = new WeatherPresenterImp(this); mWeatherPresenter.getWeatherData("2", "蘇州"); textView1 = (TextView) findViewById(R.id.textView1); textView2 = (TextView) findViewById(R.id.textView2); textView3 = (TextView) findViewById(R.id.textView3); textView4 = (TextView) findViewById(R.id.textView4); textView5 = (TextView) findViewById(R.id.textView5); textView6 = (TextView) findViewById(R.id.textView6); textView7 = (TextView) findViewById(R.id.textView7); textView8 = (TextView) findViewById(R.id.textView8); textView9 = (TextView) findViewById(R.id.textView9); }@Override public void showProgress() {LoadingUIHelper.showDialogForLoading(this,"獲取數據"); }@Override public void hideProgress() {LoadingUIHelper.hideDialogForLoading(); Toast.makeText(this,"服務器異常",Toast.LENGTH_SHORT).show(); mWeatherPresenter.onUnsubscribe(); }@Override public void loadWeather(WeatherData weatherData) {Log.d("weatherData", "weatherData==" + weatherData.toString()); textView1.setText("城市："+weatherData.getResult().getToday().getCity()); textView2.setText("日期："+weatherData.getResult().getToday().getWeek()); textView3.setText("今日溫度："+weatherData.getResult().getToday().getTemperature()); // textView4.setText("天氣標識：" +WeatherIDUtils.transfer(weatherData.getResult().getToday().getWeather_id().getFa())); textView5.setText("穿衣指數：" + weatherData.getResult().getToday().getDressing_advice()); textView6.setText("干燥指數："+weatherData.getResult().getToday().getDressing_index()); textView7.setText("紫外線強度："+weatherData.getResult().getToday().getUv_index()); textView8.setText("穿衣建議："+weatherData.getResult().getToday().getDressing_advice()); textView9.setText("旅游指數："+weatherData.getResult().getToday().getTravel_index()); }@Override protected void onDestroy() {super.onDestroy(); //取消注冊 mWeatherPresenter.onUnsubscribe(); } }

總結

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