实现商品分类列表，使用MVP+Fresco+retrofit+rxjava请求网络数据（Flowable）

 商品分类接口

https://www.zhaoapi.cn/product/getProducts?pscid=1 

请求参数：

pscid商品id字段   String类型   必传

返回数据：

见json字符串注册接口

1. 新建Android Studio项目，实现商品分类列表效果

2. 严格实现上图布局效果，屏幕适配页面美观

3. 使用MVP分包明确 避免内存泄漏

4 使用Fresco获取图片 图片路径需截取

5. 使用Retrofit请求商品分类接口

1） Retrofit加载网络数据 添加动态代理

2） RxJava异步处理数据  泛型封装对象

3） 将请求回来的数据使用recyclerview展示

1.依赖

//《Retrofit网络请求依赖》

implementation 'com.squareup.retrofit2:retrofit:2.4.0'
compile 'com.squareup.retrofit2:converter-gson:2.4.0'
//
compile 'com.squareup.retrofit2:retrofit:2.3.0'
//《Gson解析依赖》
compile 'com.google.code.gson:gson:2.2.4'
//《Fresco图片框架依赖》
compile 'com.facebook.fresco:fresco:0.14.1'
//《Recyclerview的依赖》
compile 'com.android.support:recyclerview-v7:26.1.0'
//《Butterknife依赖(黄油刀)》
compile 'com.jakewharton:butterknife:8.8.1'
annotationProcessor 'com.jakewharton:butterknife-compiler:8.8.1'
//《RXjava2的适配器》
compile 'com.squareup.retrofit2:adapter-rxjava2:2.4.0'
//《Rxjava2》
compile 'io.reactivex.rxjava2:rxjava:2.1.7'
compile 'io.reactivex.rxjava2:rxandroid:2.0.1'

2.权限

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

3.ApiService拼接接口

package com.example.dell.a1511r0418.api;

import com.example.dell.a1511r0418.model.MessageBean;
import com.example.dell.a1511r0418.model.MyDataBean;
import java.util.List;
import io.reactivex.Flowable;
import retrofit2.http.GET;
import retrofit2.http.Query;

public interface ApiService {

    //Flowable:背压
    //拼接接口
    @GET("product/getProducts")
    Flowable>> getData(@Query("pscid")String pscid);
}

4.初始化Fresco 设置使用默认设置加载图片

package com.example.dell.a1511r0418.app;

import android.app.Application;
import com.facebook.drawee.backends.pipeline.Fresco;

public class App extends Application{
    @Override
    public void onCreate() {
        super.onCreate();

        //初始化Fresco 设置使用默认设置加载图片
        Fresco.initialize(this);
    }
}

5.Retrofit 网络请求框架

package com.example.dell.a1511r0418.utils;

import com.example.dell.a1511r0418.api.ApiService;
import retrofit2.Retrofit;
import retrofit2.adapter.rxjava2.RxJava2CallAdapterFactory;
import retrofit2.converter.gson.GsonConverterFactory;

//Retrofit 网络请求框架
public class RetrofitUtils {

    //1创建一个单列模式
    private static volatile RetrofitUtils instance;
    private final Retrofit retrofit;

    //2创建一个私有的无参构造
    private RetrofitUtils(){

        //创建Retrofit
        retrofit = new Retrofit.Builder()
                .addConverterFactory(GsonConverterFactory.create())//默认Gson进行解析
                .addCallAdapterFactory(RxJava2CallAdapterFactory.create())//使用RxJava2的适配器
                .baseUrl(StringUrl.BASE_URL)//接口
                .build();

    }
    //4.创建一个静态方法，得到instance 判断是否为空
    public static RetrofitUtils getInstance(){
        if(null==instance){
            synchronized (RetrofitUtils.class){
                if(instance==null){
                    instance = new RetrofitUtils();
                }
            }
        }
        //5返回创建的instance
        return instance;
    }
    //6创建方法 方便调用
    public ApiService getApiService(){
        return  retrofit.create(ApiService.class);
    }
}

6.接口拼接

package com.example.dell.a1511r0418.utils;

public class StringUrl {
    //接口路径
    public static final String BASE_URL="https://www.zhaoapi.cn/";
}

7.接口网络获取数据的外层封装

package com.example.dell.a1511r0418.model;

//泛型封装
public class MessageBean<T> {
    private String msg;
    private String code;
    private String page;
    private  T data;

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    public String getPage() {
        return page;
    }

    public void setPage(String page) {
        this.page = page;
    }

    public T getData() {
        return data;
    }

    public void setData(T data) {
        this.data = data;
    }
}

8.接口网络获取数据的内层封装

package com.example.dell.a1511r0418.model;

public class MyDataBean {

    private double bargainPrice;
    private String createtime;
    private String detailUrl;
    private String images;
    private int itemtype;
    private int pid;
    private double price;
    private int pscid;
    private int salenum;
    private int sellerid;
    private String subhead;
    private String title;

    public double getBargainPrice() {
        return bargainPrice;
    }

    public void setBargainPrice(double bargainPrice) {
        this.bargainPrice = bargainPrice;
    }

    public String getCreatetime() {
        return createtime;
    }

    public void setCreatetime(String createtime) {
        this.createtime = createtime;
    }

    public String getDetailUrl() {
        return detailUrl;
    }

    public void setDetailUrl(String detailUrl) {
        this.detailUrl = detailUrl;
    }

    public String getImages() {
        return images;
    }

    public void setImages(String images) {
        this.images = images;
    }

    public int getItemtype() {
        return itemtype;
    }

    public void setItemtype(int itemtype) {
        this.itemtype = itemtype;
    }

    public int getPid() {
        return pid;
    }

    public void setPid(int pid) {
        this.pid = pid;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public int getPscid() {
        return pscid;
    }

    public void setPscid(int pscid) {
        this.pscid = pscid;
    }

    public int getSalenum() {
        return salenum;
    }

    public void setSalenum(int salenum) {
        this.salenum = salenum;
    }

    public int getSellerid() {
        return sellerid;
    }

    public void setSellerid(int sellerid) {
        this.sellerid = sellerid;
    }

    public String getSubhead() {
        return subhead;
    }

    public void setSubhead(String subhead) {
        this.subhead = subhead;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }
}

9.M层接口

package com.example.dell.a1511r0418.model;

public interface DataModel {
    //请求数据的方法
  void getModelData(String pscid);
}

10.M层接口实现类

package com.example.dell.a1511r0418.model;

import com.example.dell.a1511r0418.present.MyDataPresent;
import com.example.dell.a1511r0418.utils.RetrofitUtils;
import java.util.List;
import io.reactivex.Flowable;

public class MyDataModel implements DataModel{
    //创建构建器 将P层传入M层
    MyDataPresent present;
    public MyDataModel(MyDataPresent present){
        this.present=present;
    }
    //请求数据的方法
    @Override
    public void getModelData(String pscid) {
        Flowable>> flowable = RetrofitUtils.getInstance().getApiService().getData(pscid);

        //调用P层方法，将数据传给P层
        present.getBean(flowable);

    }
}

11.P层接口

package com.example.dell.a1511r0418.present;

public interface DataPresent {
    //调用请求的方法
    void getsjData(String pscid);
}

12.P层接口实现类

package com.example.dell.a1511r0418.present;

import com.example.dell.a1511r0418.model.MessageBean;
import com.example.dell.a1511r0418.model.MyDataBean;
import com.example.dell.a1511r0418.model.MyDataModel;
import com.example.dell.a1511r0418.view.DataView;
import java.util.List;
import io.reactivex.Flowable;
import io.reactivex.android.schedulers.AndroidSchedulers;
import io.reactivex.schedulers.Schedulers;
import io.reactivex.subscribers.DisposableSubscriber;

public class MyDataPresent implements DataPresent {
    private DisposableSubscriber subscriber;

    //创建方法 将V层传入P层
    DataView dataView;
    public MyDataModel myDataModel;

    public void attachView(DataView dataView) {
        this.dataView = dataView;
    }

    //防止泄露
    public void detachView() {
        if (dataView != null) {
            dataView = null;
        }
        if (!subscriber.isDisposed()){
            subscriber.dispose();
        }
    }

    //创建请求的方法
    @Override
    public void getsjData(String pscid) {

        //实例化M层 将P层传给M层
        myDataModel = new MyDataModel(this);
        //调用M层方法 将pscid传给M层
        myDataModel.getModelData(pscid);
    }

    //获取请求后数据
    public void getBean(Flowable>> flowable) {
        //转换线程
            flowable.subscribeOn(Schedulers.io())//Io线程 网络请求
                    .observeOn(AndroidSchedulers.mainThread())//主线程 更新Ui
                    .subscribeWith(new DisposableSubscriber>>() {

                        //下一个
                        @Override
                        public void onNext(MessageBean> listMessageBean) {

                            //判断返回的数据是否为空
                            if(listMessageBean!=null){
                                List list = listMessageBean.getData();

                                //不为空则将数据传给V层
                                if(list!=null){
                                    dataView.Success(list);
                                }
                            }
                        }
                        //异常 传给V层
                        @Override
                        public void onError(Throwable t) {
                            dataView.Eroor(t);
                        }

                        //成功
                        @Override
                        public void onComplete() {}
                    });


    }
}

13.V层接口

package com.example.dell.a1511r0418.view;

public interface DataView {
    //成功和失败的方法
    void Success(Object o);
    void Eroor(Throwable t);
}

14.V层接口实现类

package com.example.dell.a1511r0418.view;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import com.example.dell.a1511r0418.R;
import com.example.dell.a1511r0418.adapter.MyAdaptr;
import com.example.dell.a1511r0418.model.MyDataBean;
import com.example.dell.a1511r0418.present.MyDataPresent;
import java.util.List;
import butterknife.BindView;
import butterknife.ButterKnife;

public class MainActivity extends AppCompatActivity implements DataView {

    @BindView(R.id.mian_rcv)
    RecyclerView mian_Rcv;
    private MyDataPresent myDataPresent;
    private MyAdaptr myAdaptr;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);

        //设置布局
        mian_Rcv.setLayoutManager(new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false));

        //实例化P层
        myDataPresent = new MyDataPresent();

        //调用P层方法 将pscid传给P层
        myDataPresent.getsjData("1");

        //调用P层方法 将V层传给P层
        myDataPresent.attachView(this);
    }

    //成功
    @Override
    public void Success(Object o) {

        //因参数是Object 所有需要转成自己数据的类型
        List list = (List) o;
        Log.e("+++++", "Success: "+list.size());

        //创建适配器
        myAdaptr = new MyAdaptr(this,list);

        //RecyclerView调用适配器
        mian_Rcv.setAdapter(myAdaptr);

    }

    //失败
    @Override
    public void Eroor(Throwable t) {
        Log.e("======", "Eroor: "+t.getMessage() );
    }

    //当Activity销毁时 需将V层置空 防止内存泄露
    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (myDataPresent!=null){
            myDataPresent.detachView();
        }
    }
}

15.适配器

package com.example.dell.a1511r0418.adapter;

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.example.dell.a1511r0418.R;
import com.example.dell.a1511r0418.model.MyDataBean;
import com.facebook.drawee.view.SimpleDraweeView;
import java.util.List;

public class MyAdaptr extends RecyclerView.Adapter{
    Context context;
    List list;
    public MyAdaptr(Context context, List list) {
        this.context=context;
        this.list=list;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        //引入布局
        View view = View.inflate(context, R.layout.rcv_item, null);

        //创建MyViewHolder 将View传过去
        MyViewHolder myViewHolder = new MyViewHolder(view);
        return myViewHolder;
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        MyViewHolder myViewHolder = (MyViewHolder) holder;

        //图片需截取 先用其中url一个代替
        //String imhurl="https://m.360buyimg.com/n0/jfs/t9004/210/1160833155/647627/ad6be059/59b4f4e1N9a2b1532.jpg!q70.jpg";

        //切割图片路径
        String imhurl="";
        String images = list.get(position).getImages();
        String[] split = images.split("\\|");
        for (int i = 0;ilength;i++){
            imhurl=split[i];
        }

        //为控件进行赋值
        myViewHolder.rcv_img.setImageURI(imhurl);
        myViewHolder.rcv_title.setText(list.get(position).getTitle());
        myViewHolder.rcv_price.setText("￥"+list.get(position).getPrice());

    }

    //条目数量
    @Override
    public int getItemCount() {
        return list.size();
    }

    class MyViewHolder extends RecyclerView.ViewHolder{

        private final SimpleDraweeView rcv_img;
        private final TextView rcv_title;
        private final TextView rcv_price;

        public MyViewHolder(View view) {
            super(view);

            //找到布局文件的控件的ID
            rcv_img = view.findViewById(R.id.rcv_img);
            rcv_title = view.findViewById(R.id.rcv_title);
            rcv_price = view.findViewById(R.id.rcv_price);

        }
    }
}

16.主布局文件

xml version="1.0" encoding="utf-8"?>
<LinearLayout 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="com.example.dell.a1511r0418.view.MainActivity">

    
    <android.support.v7.widget.RecyclerView
        android:id="@+id/mian_rcv"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
    android.support.v7.widget.RecyclerView>
    

LinearLayout>

17.条目布局

xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">


    
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:padding="10px">

        <com.facebook.drawee.view.SimpleDraweeView
            android:id="@+id/rcv_img"
            android:layout_width="150px"
            android:layout_height="150px" />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            android:padding="10px">
            <TextView
                android:id="@+id/rcv_title"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="每个中秋都不能简单"
                android:padding="10px"/>
            <TextView
                android:id="@+id/rcv_price"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:padding="10px"
                android:text="￥99.99"/>

        LinearLayout>
    LinearLayout>

LinearLayout>