带你封装本身的MVP+Retrofit+RxJava2框架（一）

前言

文本已经收录到个人Github我的博客，欢迎大佬们光临寒舍：个人GIthub博客

看完本篇文章的，能够看下带你封装本身的MVP+Retrofit+RxJava2框架（二），里面封装获得了改进

本篇文章须要已经具有的知识：

• MVP的概念和基本使用
• Retrofit框架的基本使用
• RxJava2框架的基本使用
• ButterKnife框架的基本使用
• Base基类的概念

学习清单：

• Activity和Fragment基类的封装
• MVP的封装使用

一.为何要封装这套框架呢？

在搞清楚这个问题以前，咱们回顾一下基本概念

RxJava: ReactiveX 在JVM上的一个实现，ReactiveX使用Observable序列组合异步和基于事件的程序；掌握了它，你能够优美地处理异步任务和事件的回调

Retrofit:一个 RESTful 的 HTTP 网络请求框架的封装，网络请求的工做本质上是 OkHttp 完成，而 Retrofit 仅负责 网络请求接口的封装:掌握了它，你能优美地进行网络请求。

MVP：一种解耦模型和视图的模式，是如今不少公司的主流模式。

因而可知，在平时的开发中熟练运用这种模式，不只能够知足生活中大部分应用程序的场景，还能够为未来的工做积攒宝贵的实战经验。

二.核心用法

本项目基于Android X 进行构建，完整代码可在个人github上下载:带你封装本身的MVP+Retrofit+RxJava2框架

首先，看一下咱们项目的基本结构，下面笔者将为你们详细介绍每一个类的相关信息

2.1 基类base

Base基类是封装了一些基类，方便后面新建新的activity或者fragment，减小耦合

2.1.1 BaseActivity

这个类是Activity的基类，注意与下面的BaseMvpActivity区分开

/** * Description : BaseActivity 基类活动 * * @author XuCanyou666 * @date 2020/2/2 */


public abstract class BaseActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(getLayoutId());
        initPresenter();
        initViews();
        ButterKnife.bind(this);
    }


    /** * 抽象方法：实例化Presenter */
    protected abstract void initPresenter();

    /** * 抽象方法：初始化控件，通常在BaseActivity中经过ButterKnife来绑定，因此该方法内部通常咱们初始化界面相关的操做 * * @return 控件 */
    protected abstract void initViews();


    /** * 抽象方法：获得布局id * * @return 布局id */
    protected abstract int getLayoutId();


    /** * 启动Fragment * * @param id id * @param fragment 碎片 */
    protected void startFragment(int id, Fragment fragment) {
        FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
        fragmentTransaction.add(id, fragment);
        fragmentTransaction.commit();
    }

}

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2.1.2 BaseView

一个接口，说明了每个View基本须要的一些操做

package com.users.xucanyou666.rxjava2_retrofit_mvp.base;


/** * created by xucanyou666 * on 2020/1/31 18:26 * email：913710642@qq.com */
public interface BaseView {

    /** * 显示进度框 */
    void showProgressDialog();


    /** * 关闭进度框 */
    void hideProgressDialog();


    /** * 出错信息的回调 * * @param result 错误信息 */
    void onError(String result);



}

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2.1.3 BaseMvpActivity--MVP活动的基类

继承自BaseActivity,它是MVP活动的基类，封装好了presenter的相关操做

package com.users.xucanyou666.rxjava2_retrofit_mvp.base;


/** * created by xucanyou666 MVP活动的基类，封装好了presenter的相关操做 * on 2019/12/24 20:53 * email：913710642@qq.com */

public abstract class BaseMvpActivity<V extends BaseView, P extends BasePresenter> extends BaseActivity {

    private P presenter;

    /** * 初始化presenter */
    @Override
    protected void initPresenter() {
        presenter = createPresenter();
        if (presenter != null) {
            presenter.attachView((V) this);
        }
    }

    /** * 建立presenter * * @return Presenter */
    protected abstract P createPresenter();


    /** * 获得presenter * * @return presenter */
    protected P getPresenter() {
        return presenter;
    }

    /** * 销毁 */
    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (presenter != null) {
            presenter.detachView();
        }
    }


}

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2.1.4 BaseFragment--Fragment的基类

须要注意的是，这里用了ButterKnife框架，对碎片进行了绑定和解绑操做

/** * Fragment的基类，封装了一些Fragment的相关操做 * created by xucanyou666 * on 2020/1/31 16:21 * email：913710642@qq.com */
public abstract class BaseFragment<T extends BasePresenter> extends Fragment implements BaseView {
    protected T mPresenter;
    protected Context mContext;
    protected Bundle mBundle;
    protected Unbinder unbinder;
    protected View view;

    /** * 恢复数据 * * @param outState bundle */
    @Override
    public void onSaveInstanceState(@NonNull Bundle outState) {
        super.onSaveInstanceState(outState);
        if (mBundle != null) {
            outState.putBundle("bundle", mBundle);
        }
    }

    /** * 绑定activity * * @param context context */
    @Override
    public void onAttach(@NonNull Context context) {
        super.onAttach(context);
        mContext = context;
    }

    /** * 运行在onAttach以后，能够接收别人传递过来的参数，实例化对象 * 能够解决返回的时候页面空白的bug * * @param savedInstanceState */
    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (savedInstanceState != null) {
            mBundle = savedInstanceState.getBundle("bundle");
        } else {
            mBundle = getArguments() == null ? new Bundle() : getArguments();
        }
        //初始化presenter
        mPresenter = initPresenter();
    }

    protected T getPresenter() {
        return mPresenter;
    }


    /** * 运行在onCreate以后，生成View视图 * * @param inflater * @param container * @param savedInstanceState * @return */
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        view = initView(inflater, container, savedInstanceState);
        unbinder = ButterKnife.bind(this, view);
        return view;
    }

    /** * 运行在onCreateView以后 * 加载数据 * * @param savedInstanceState */
    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        mPresenter.attachView(this);

    }


    /** * 跳转Fragment * * @param toFragment 跳转去的fragment */
    public void startFragment(Fragment toFragment) {
        Log.d(TAG, "haha");
        startFragment(toFragment, null);
    }

    /** * 跳转Fragment * * @param toFragment 跳转到的fragment * @param tag fragment的标签 */
    public void startFragment(Fragment toFragment, String tag) {
        FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
        fragmentTransaction.hide(this).add(android.R.id.content, toFragment, tag);
        fragmentTransaction.addToBackStack(tag);
        fragmentTransaction.commitAllowingStateLoss();
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        unbinder.unbind();
    }

    /** * fragment进行回退 * 相似于activity的OnBackPress */
    public void onBack() {
        getFragmentManager().popBackStack();
    }

    @Override
    public void onDetach() {
        mPresenter.detachView();
        super.onDetach();
    }

    /** * 初始化Fragment应有的视图 * * @return view */
    public abstract View initView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState);


    /** * 建立presenter * * @return <T extends BasePresenter> 必须是BasePresenter的子类 */
    public abstract T initPresenter();

    /** * 获得context * * @return context */
    @Override
    public Context getContext() {
        return mContext;
    }

    /** * 获得bundle * * @return bundle */
    public Bundle getBundle() {
        return mBundle;
    }

    /** * 获得fragment * * @return fragment */
    public Fragment getFragment() {
        return this;
    }

}
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2.1.5 BasePresenter

Presenter的基类，这里的CompositeDisposable主要用途是及时取消订阅，以防止内存泄漏，具体CompositeDisposable的用法可参照Rxjava关于Disposable你应该知道的事

/** * created by xucanyou666 * on 2020/1/16 17:12 * email：913710642@qq.com */
public abstract class BasePresenter<V extends BaseView> {
    //将全部正在处理的Subscription都添加到CompositeSubscription中。统一退出的时候注销观察
    private CompositeDisposable mCompositeDisposable;
    private V baseView;

    /** * 和View绑定 * * @param baseView */
    public void attachView(V baseView) {
        this.baseView = baseView;
    }

    /** * 解绑View,该方法在BaseMvpActivity类中被调用 */
    public void detachView() {
        baseView = null;
        // 在界面退出等须要解绑观察者的状况下调用此方法统一解绑，防止Rx形成的内存泄漏
        if (mCompositeDisposable != null) {
            mCompositeDisposable.dispose();
        }
    }

    /** * 获取View * * @return view */
    public V getMvpView() {
        return baseView;
    }



    /** * 将Disposable添加,在每次网络访问以前初始化时进行添加操做 * * @param subscription subscription */
    public void addDisposable(Disposable subscription) {
        //csb 若是解绑了的话添加 sb 须要新的实例不然绑定时无效的
        if (mCompositeDisposable == null || mCompositeDisposable.isDisposed()) {
            mCompositeDisposable = new CompositeDisposable();
        }
        mCompositeDisposable.add(subscription);
    }

}

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2.1.6 MyApplication

封装了一个能够全局获取context的方法，参考写法自：《第一行代码--第二版》，须要注意的是，记得在AndroidManifest中注册application

package com.users.xucanyou666.rxjava2_retrofit_mvp.base;


import android.app.Application;
import android.content.Context;

/** * 基类 * created by xucanyou666 * on 2019/11/2 14:46 * email：913710642@qq.com * @author xucanyou666 */
public class MyApplication extends Application {
    private static Context context;

    @Override
    public void onCreate() {
        super.onCreate();
        context = getApplicationContext();
    }

    public static Context getContext() {
        return context;
    }
}

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2.2 工具类 util

2.2.1 RetrofitManager

Retrofit单例工具类

/** * Retrofit单例工具类 * created by xucanyou666 * on 2020/1/16 16:38 * email：913710642@qq.com */
public class RetrofitManager {
    private Retrofit mRetrofit;


    //构造器私有，这个工具类只有一个实例
    private RetrofitManager() {
        OkHttpClient.Builder httpClientBuilder = new OkHttpClient.Builder();
        httpClientBuilder.connectTimeout(15, TimeUnit.SECONDS);
        mRetrofit = new Retrofit.Builder()
                .client(httpClientBuilder.build())
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
                .baseUrl(BASE_URL)
                .build();
    }


    /** * 静态内部类单例模式 * * @return */
    public static RetrofitManager getInstance() {
        return Inner.retrofitManager;
    }

    private static class Inner {
        private static final RetrofitManager retrofitManager = new RetrofitManager();
    }


    /** * 利用泛型传入接口class返回接口实例 * * @param ser 类 * @param <T> 类的类型 * @return Observable */
    public <T> T createRs(Class<T> ser) {
        return mRetrofit.create(ser);
    }
}
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2.2.2 RxJavaUtil

RxJava的工具类，执行线程调度工做

/** * created by xucanyou666 * on 2019/11/17 19:20 * email：913710642@qq.com * * @author xucanyou666 */
public class RxJavaUtil {
    /** * 线程调度工做 * * @param observable 被观察者 * @param <T> 类型 */
    public static <T> Observable toSubscribe(Observable<T> observable) {
        return observable.subscribeOn(Schedulers.io())
                .unsubscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread());
    }

}

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2.3 常量类 contant

常量池，特别感谢api open网提供的免费api

/** * created by xucanyou666 * on 2019/11/17 19:01 * email：913710642@qq.com */
public class StaticQuality {
    public static final String BASE_URL="https://api.gushi.ci/";
}
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2.4 接口管理器 contract

这里集中了一些Model层,Presenter层,View层的与诗歌相关的接口

/** * 诗歌的接口管理器 * created by xucanyou666 * on 2020/2/2 15:33 * email：913710642@qq.com */
public interface IPoetryContract {
    interface IPoetryModel {
        /** * 获得诗歌 * * @return 诗歌 */
        Observable<PoetryEntity> getPoetry();
    }

    interface IPoetryPresenter {
        void getPoetry();
    }

    interface IPoetryView extends BaseView {
        /** * @param author 做者 */
        void searchSuccess(String author);
    }
}

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2.5 实体类 entity

/** * 诗歌的实体类 * created by xucanyou666 * on 2020/1/23 21:23 * email：913710642@qq.com * API返回示例： * { * "content": "胡瓶落膊紫薄汗，碎叶城西秋月团。", * "origin": "从军行七首", * "author": "王昌龄", * "category": "古诗文-天气-月亮" * } */
public class PoetryEntity {
    private String content; //诗歌内容
    private String origin; //来源
    private String author; //做者
    private String category; //分类

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    public String getOrigin() {
        return origin;
    }

    public void setOrigin(String origin) {
        this.origin = origin;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public String getCategory() {
        return category;
    }

    public void setCategory(String category) {
        this.category = category;
    }
}

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2.6 retrofit接口 iApiService

/** * retrofit接口 * created by xucanyou666 * on 2020/1/23 21:25 * email：913710642@qq.com */
public interface GetPoetryEntity {
    /** * 获取古诗词 * * @return 古诗词 */
    @GET("all.json")
    Observable<PoetryEntity> getPoetry();
}
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2.7 视图层 view

这里为了减小代码量，方便读者们掌握核心操做，故View层都是用的同一个presenter和model，仅做学习参考

2.7.1 MainActivity

须要注意的是，这里BaseMvpActivity<activity, presenter>,activity填入的是当前的activity，presenter填入的是对应的presenter

/** * Description : MainActivity * * @author XuCanyou666 * @date 2020/2/3 */

public class MainActivity extends BaseMvpActivity<MainActivity, PoetryPresenter> implements IPoetryContract.IPoetryView {

    @BindView(R.id.btn_get_poetry)
    Button btnGetPoetry;
    @BindView(R.id.tv_poetry_author)
    TextView tvPoetryAuthor;
    @BindView(R.id.btn_goto_fragment)
    Button btnGotoFragment;
    @BindView(R.id.ll)
    LinearLayout ll;

    @Override
    protected void initViews() {

    }

    @Override
    protected int getLayoutId() {
        return R.layout.activity_main;
    }

    @Override
    protected PoetryPresenter createPresenter() {
        return PoetryPresenter.getInstance();
    }

    @Override
    public void searchSuccess(String author) {
        tvPoetryAuthor.setText(author);
    }

    @Override
    public void showProgressDialog() {

    }

    @Override
    public void hideProgressDialog() {

    }

    @Override
    public void onError(String result) {
        Toast.makeText(MyApplication.getContext(), result, Toast.LENGTH_SHORT).show();
    }


    @OnClick({R.id.btn_get_poetry, R.id.btn_goto_fragment})
    public void onViewClicked(View view) {
        switch (view.getId()) {
            case R.id.btn_get_poetry:
                getPresenter().getPoetry();
                break;
            case R.id.btn_goto_fragment:
                startFragment(R.id.ll, new MainFragment());
                break;
            default:
                break;
        }
    }
}
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2.7.2 MainFragment

/** * Description : MainFragment * * @author XuCanyou666 * @date 2020/2/2 */


public class MainFragment extends BaseFragment<PoetryPresenter> implements IPoetryContract.IPoetryView {

    @BindView(R.id.btn_get_poetry)
    Button btnGetPoetry;
    @BindView(R.id.tv_poetry_author)
    TextView tvPoetryAuthor;

    @Override
    public View initView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_main, container, false);
    }

    @Override
    public PoetryPresenter initPresenter() {
        return PoetryPresenter.getInstance();
    }


    @Override
    public void showProgressDialog() {

    }

    @Override
    public void hideProgressDialog() {

    }

    @Override
    public void onError(String result) {
        Toast.makeText(MyApplication.getContext(), result, Toast.LENGTH_SHORT).show();

    }

    @OnClick(R.id.btn_get_poetry)
    public void onViewClicked() {
        getPresenter().getPoetry();
    }

    @Override
    public void searchSuccess(String author) {
        tvPoetryAuthor.setText(author);
    }
}
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2.8 presenter层

/** * created by xucanyou666 * on 2020/1/16 17:09 * email：913710642@qq.com */
public class PoetryPresenter extends BasePresenter<IPoetryContract.IPoetryView> implements IPoetryContract.IPoetryPresenter {

    private static final String TAG = "PoetryPresenter";

    private PoetryEntity mPoetryEntity;
    private PoetryModel mPoetryModel;

    private PoetryPresenter() {
        mPoetryModel = PoetryModel.getInstance();
    }

    public static PoetryPresenter getInstance() {
        return Inner.instance;
    }

    private static class Inner {
        private static final PoetryPresenter instance = new PoetryPresenter();
    }

    /** * 获得诗歌 */
    @Override
    public void getPoetry() {
        Observable observable = mPoetryModel.getPoetry().doOnSubscribe(new Consumer<Disposable>() {
            @Override
            public void accept(Disposable disposable) throws Exception {
                addDisposable(disposable);
            }
        });
        observable = RxJavaUtil.toSubscribe(observable);
        observable.subscribe(new Observer<PoetryEntity>() {
            @Override
            public void onSubscribe(Disposable d) {
            }

            @Override
            public void onNext(PoetryEntity poetryEntity) {
                mPoetryEntity = poetryEntity;
            }

            @Override
            public void onError(Throwable e) {
                getMvpView().onError(e.getMessage());
                Log.d(TAG, "onError: " + e.getMessage());
            }

            @Override
            public void onComplete() {
                if (mPoetryEntity != null) {
                    getMvpView().searchSuccess(mPoetryEntity.getAuthor());
                }
            }
        });

    }
}


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2.9 model层

/** * created by xucanyou666 * on 2020/1/16 17:06 * email：913710642@qq.com */
public class PoetryModel implements IPoetryContract.IPoetryModel {


    private PoetryModel() {

    }

    public static PoetryModel getInstance() {
        return Inner.instance;
    }

    private static class Inner {
        private static final PoetryModel instance = new PoetryModel();
    }


    /** * 获取古诗词 * * @return 古诗词 */
    @Override
    public Observable<PoetryEntity> getPoetry() {
        return RetrofitManager.getInstance().createRs(GetPoetryEntity.class).getPoetry();
    }
}
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2.10 app-build.gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    defaultConfig {
        applicationId "com.users.xucanyou666.rxjava2_retrofit_mvp"
        minSdkVersion 19
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    // RxJava
    implementation 'io.reactivex.rxjava2:rxjava:2.1.12'
    implementation 'com.squareup.retrofit2:retrofit:2.6.0'
    // Retrofit和jxjava关联
    implementation 'com.squareup.retrofit2:adapter-rxjava2:2.4.0'
    // Retrofit使用Gson转换
    implementation 'com.squareup.retrofit2:converter-gson:2.4.0'
    // RxAndroid
    implementation 'io.reactivex.rxjava2:rxandroid:2.0.2'
    //引入ButterKnife
    implementation "com.jakewharton:butterknife:10.2.0"
    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
    annotationProcessor "com.jakewharton:butterknife-compiler:10.2.0"

    implementation "com.google.android.material:material:1.0.0"
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
}

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三.我在使用中遇到的问题

3.1 网络权限忘记授予

解决措施：加上权限便可

<uses-permission android:name="android.permission.INTERNET" />
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3.2 ButterKnife框架版本问题

使用ButterKnife框架的时候

当是androidX的时候，须要implementation 10.2.0版本的ButterKnife

//引入ButterKnife
    implementation "com.jakewharton:butterknife:10.2.0"
    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
    annotationProcessor "com.jakewharton:butterknife-compiler:10.2.0"
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当是android 28等其余版本的时候，能够导入8.4.0版本的ButterKnife（导入10.2.0版本会出错）

implementation 'com.jakewharton:butterknife:8.4.0'
    annotationProcessor 'com.jakewharton:butterknife-compiler:8.4.0' 
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3.3 ButterKnife须要Java 1.8以上的支持

compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    } 
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3.4 Fragment中点击事件失效的问题

点击事件发生的场景：Fragment中初始化控件没有用butterKnife框架

解决措施以下：

• 将控件的初始化防止onCreateView中
• 将控件的点击事件的代码放在onActivityCreated中

---

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本文参考连接：

• Rxjava关于Disposable你应该知道的事
• Mvp实战心得(二)---Base基类的封装
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