使用 RxJava+Retrofit进行数据请求，并放在RecycleView中使用fresco加载图片

首先是依赖：

 compile ‘com.squareup.retrofit2:retrofit:2.0.1‘
    compile ‘com.squareup.retrofit2:converter-gson:2.0.1‘
    compile ‘com.squareup.retrofit2:adapter-rxjava:2.0.1‘
    compile ‘io.reactivex:rxandroid:1.1.0‘
    compile ‘com.squareup.okhttp3:logging-interceptor:3.4.1‘
    compile ‘com.android.support:mediarouter-v7:25.0.0‘
    compile ‘com.android.support:recyclerview-v7:25.0.0‘
    compile ‘com.nostra13.universalimageloader:universal-image-loader:1.9.5‘
    compile ‘com.facebook.fresco:fresco:0.14.1‘
    compile ‘com.facebook.fresco:animated-base-support:0.14.1‘
    compile ‘com.facebook.fresco:animated-gif:0.14.1‘
    compile ‘com.facebook.fresco:webpsupport:0.14.1‘
    compile ‘com.facebook.fresco:animated-webp:0.14.1‘
    compile ‘com.facebook.fresco:imagepipeline-okhttp3:0.14.1‘

然后是权限：

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

然后需要定义一个Apiservice接口（get里面写分类识别）：

 @GET("type/1/p/1")
    Observable<Home> gethomes();

然后是HomeAdapter类（这个是Recycleview的适配器，如果不明白，可以找找本人的随笔哦）

public class HomeAdapter extends RecyclerView.Adapter<HomeAdapter.MyViewHolder>
{ List<Home.DataBean> mDatas;
    Context context;

    public HomeAdapter(List<Home.DataBean> mDatas, Context context) {
        this.mDatas = mDatas;
        this.context = context;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
    {
        MyViewHolder holder = new MyViewHolder(LayoutInflater.from(
                context).inflate(R.layout.item_home, parent,
                false));
        return holder;
    }

    @Override
    public int getItemCount()
    {
        return mDatas.size();
    }

    class MyViewHolder extends RecyclerView.ViewHolder
    {

        TextView tv;
        SimpleDraweeView img;
        public MyViewHolder(View view)
        {
            super(view);
            tv = (TextView) view.findViewById(R.id.id_num);
            img= (SimpleDraweeView) view.findViewById(R.id.main_simple_drawee_view);
        }
    }
    public interface OnItemClickLitener
    {
        void onItemClick(View view, int position);
        void onItemLongClick(View view , int position);
    }

    private OnItemClickLitener mOnItemClickLitener;

    public void setOnItemClickLitener(OnItemClickLitener mOnItemClickLitener)
    {
        this.mOnItemClickLitener = mOnItemClickLitener;
    }

    @Override
    public void onBindViewHolder(final MyViewHolder holder, final int position)
    {
        holder.tv.setText(mDatas.get(position).getNews_title());
        String url = mDatas.get(position).getPic_url();
        if (url.equals("")||url==null){
            holder.img.setImageResource(R.mipmap.ic_launcher);
        }else {
            Uri uri =  Uri.parse(url);
            DraweeController controller = Fresco.newDraweeControllerBuilder()
                    .setUri(uri)
                    .setAutoPlayAnimations(true)
                    .build();
            holder.img.setController(controller);
        }

        // 如果设置了回调，则设置点击事件
        if (mOnItemClickLitener != null)
        {
            holder.itemView.setOnClickListener(new View.OnClickListener()
            {
                @Override
                public void onClick(View v)
                {
                    int pos = holder.getLayoutPosition();
                    mOnItemClickLitener.onItemClick(holder.itemView, pos);
                }
            });

            holder.itemView.setOnLongClickListener(new View.OnLongClickListener()
            {
                @Override
                public boolean onLongClick(View v)
                {
                    int pos = holder.getLayoutPosition();
                    mOnItemClickLitener.onItemLongClick(holder.itemView, pos);
                    return false;
                }
            });
        }
    }

}

API中放你的接口：

public class API {
    public static final String HOME_URL="http://api.expoon.com/AppNews/getNewsList/";
}

MainActivity

public class MainActivity extends AppCompatActivity {
    RecyclerView mRecyclerView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mRecyclerView = (RecyclerView) findViewById(R.id.id_recyclerview);
        mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
        mRecyclerView.setItemAnimator(new DefaultItemAnimator());
        getmadata();
    }

    public void getmadata() {
        Retrofit retrofit = new Retrofit.Builder().baseUrl(API.HOME_URL).addConverterFactory(GsonConverterFactory.create()).addCallAdapterFactory(RxJavaCallAdapterFactory.create()).build();
        Apiservice apiservice = retrofit.create(Apiservice.class);
        Observable<Home> homes = apiservice.gethomes();
        homes.subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new Observer<Home>() {
                    @Override
                    public void onCompleted() {

                    }
                    @Override
                    public void onError(Throwable e) {

                    }

                    @Override
                    public void onNext(Home home) {
                        List<Home.DataBean> data = home.getData();
                        mRecyclerView.setAdapter(new HomeAdapter(data,MainActivity.this));
                    }
                });
    }
}

MyApp配置fresco：

public class MyApp extends Application {
    public static MyApp mInstance;
    @Override
    public void onCreate() {
        super.onCreate();
        Fresco.initialize(this);
        mInstance = this;
    }
    public static MyApp getInstance() {
        return mInstance;
    }
}

然后就是布局了,首先是主布局（把recycleview写上）：

<android.support.v7.widget.RecyclerView
        android:id="@+id/id_recyclerview"
        android:divider="#ffff0000"
        android:dividerHeight="10dp"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

然后好需要一个条目布局item_home：

 <com.facebook.drawee.view.SimpleDraweeView
        android:layout_width="100dp"
        android:layout_height="100dp"
        fresco:roundAsCircle="true"
        fresco:roundingBorderColor="@android:color/holo_blue_light"
        fresco:roundingBorderWidth="5dp"
        android:id="@+id/main_simple_drawee_view"
        fresco:placeholderImage="@mipmap/ic_launcher"/>
    <TextView
        android:id="@+id/id_num"
        android:layout_below="@id/main_simple_drawee_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="1" />

这样就写好了