简单实现断点续传+MVP+Retrofit+RxJava

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.nostra13.universalimageloader:universal-image-loader:1.9.5'    compile 'com.squareup.okhttp3:logging-interceptor:3.4.1'    compile 'com.android.support:mediarouter-v7:25.0.0'    compile 'com.android.support:appcompat-v7:25.0.0'    compile 'com.android.support:recyclerview-v7:25.0.0'    compile 'com.android.support:appcompat-v7:23.4.0'    compile 'com.facebook.fresco:fresco:0.11.0'    compile 'com.loopj.android:android-async-http:1.4.9'    compile 'com.jcodecraeer:xrecyclerview:1.3.2'

Api类

public class Api {    public static final String Urljson1 = "https://api.tianapi.com/wxnew/";}

ApiService类

public interface ApiService {    @POST    Observable<Users> getUser(@Url String url);}

IModel类

public interface IModel {    void getJson(String url);}

UserModel类

import android.util.Log;import com.six.zhouerlianxi.Apiservers.ApiService;import com.six.zhouerlianxi.bean.Users;import java.util.ArrayList;import retrofit2.Retrofit;import retrofit2.adapter.rxjava.RxJavaCallAdapterFactory;import retrofit2.converter.gson.GsonConverterFactory;import rx.Observable;import rx.Observer;import rx.android.schedulers.AndroidSchedulers;import rx.schedulers.Schedulers;/** * Created by wangjiao on 2017/11/11. */public class UserModel implements IModel{    ArrayList<Users.NewslistBean> list;    //刷新加载    String path;    public UserModel(String path) {        this.path = path;    }    private OnFinish onFinish;    public interface OnFinish{        void OnFinishListener(ArrayList<Users.NewslistBean> list);    }    public void setOnFinish(OnFinish finish){        this.onFinish=finish;    }    @Override    public void getJson(String url) {        list = new ArrayList<>();        Retrofit retrofit = new Retrofit.Builder().baseUrl(url).addConverterFactory(GsonConverterFactory.create()).addCallAdapterFactory(RxJavaCallAdapterFactory.create()).build();        ApiService apiService = retrofit.create(ApiService.class);        //加载        final Observable<Users> home = apiService.getUser(path);        home.subscribeOn(Schedulers.io())                .observeOn(AndroidSchedulers.mainThread())                .subscribe(new Observer<Users>() {                    @Override                    public void onCompleted() {                    }                    @Override                    public void onError(Throwable e) {                    }                    @Override                    public void onNext(Users homeBean) {                        list = (ArrayList<Users.NewslistBean>) homeBean.getNewslist();                        Log.d("1111111111",list.get(0).getTitle());                        onFinish.OnFinishListener(list);                    }                });    }}

IView类

public interface IView {    void getUser(ArrayList<Users.NewslistBean> list);}

UserPresenter类

import com.six.zhouerlianxi.bean.Users;import com.six.zhouerlianxi.model.UserModel;import com.six.zhouerlianxi.view.IView;import java.util.ArrayList;/** * Created by wangjiao on 2017/11/11. */public class UserPresenter implements UserModel.OnFinish{    private final IView userView;    private final UserModel userModel;    //加载string url    public UserPresenter(IView userView,String url) {        this.userView = userView;        this.userModel = new UserModel(url);        userModel.setOnFinish(this);    }    public void setNews(String url){        userModel.getJson(url);    }    @Override    public void OnFinishListener(ArrayList<Users.NewslistBean> list) {        userView.getUser(list);    }}

MainActivity类

import android.os.Bundle;import android.os.Environment;import android.os.Handler;import android.os.Message;import android.os.SystemClock;import android.support.v7.app.AppCompatActivity;import android.support.v7.widget.LinearLayoutManager;import android.text.TextUtils;import android.util.Log;import android.view.View;import android.widget.LinearLayout;import android.widget.ProgressBar;import android.widget.TextView;import android.widget.Toast;import com.jcodecraeer.xrecyclerview.XRecyclerView;import com.loopj.android.http.HttpGet;import com.six.zhouerlianxi.API.Api;import com.six.zhouerlianxi.adapter.HomeAdapter;import com.six.zhouerlianxi.adapter.OnItemClickLitener;import com.six.zhouerlianxi.bean.Users;import com.six.zhouerlianxi.presenters.UserPresenter;import com.six.zhouerlianxi.view.IView;import java.io.BufferedReader;import java.io.File;import java.io.FileReader;import java.io.FileWriter;import java.io.InputStream;import java.io.RandomAccessFile;import java.util.ArrayList;import cz.msebera.android.httpclient.Header;import cz.msebera.android.httpclient.HttpResponse;import cz.msebera.android.httpclient.client.HttpClient;import cz.msebera.android.httpclient.client.methods.HttpHead;import cz.msebera.android.httpclient.impl.client.DefaultHttpClient;public class MainActivity extends AppCompatActivity implements IView {    UserPresenter userPresenter;    private HomeAdapter adapter;    private XRecyclerView xr;    LinearLayout line1;    protected static final String TAG = "OtherActivity";    //下载线程的数量    private final static int threadsize = 3;    protected static final int SET_MAX = 0;    public static final int UPDATE_VIEW = 1;    private boolean flag = false;//是否在下载    private ProgressBar pb;    private TextView tv_info;    //加载    String url;    int a=1;    private ArrayList<Users.NewslistBean> newslistBeen;    String uri = "https://zxpic.gtimg.com/infonew/0/wechat_pics_-58717788.jpg/640";    //显示进度和更新进度    private Handler mHandler = new Handler(){        public void handleMessage(android.os.Message msg) {            switch (msg.what) {                case SET_MAX://设置进度条的最大值                    int filelength = msg.arg1;                    pb.setMax(filelength);                    break;                case UPDATE_VIEW://更新进度条  和 下载的比率                    int len = msg.arg1;//新下载的长度                    pb.setProgress(pb.getProgress()+len);//设置进度条的刻度                    int max = pb.getMax();//获取进度的最大值                    int progress = pb.getProgress();//获取已经下载的数据量                    //  下载：30    总：100                    int result = (progress*100)/max;                    tv_info.setText("下载:"+result+"%");                    if (result==100){                        line1.setVisibility(View.GONE);                    }                    break;                default:                    break;            }        };    };    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        //加载        newslistBeen = new ArrayList<Users.NewslistBean>();        url= "?key=8d6e3228d25298f13af4fc40ce6c9679&num=20&page="+a;        xr = (XRecyclerView) findViewById(R.id.xre_xrv);        pb = (ProgressBar) findViewById(R.id.progressBar);        line1 = (LinearLayout) findViewById(R.id.line1);        tv_info = (TextView) findViewById(R.id.text3);        userPresenter = new UserPresenter(this,url);        userPresenter.setNews(Api.Urljson1);        String name = getFileName(uri);        File file = new File(Environment.getExternalStorageDirectory(), name);        if (file.exists()){//文件存在回显            //获取文件的大小            int filelength = (int) file.length();            pb.setMax(filelength);            try {                //统计原来所有的下载量                int count = 0;                //读取下载记录文件                for (int threadid = 0; threadid < threadsize; threadid++) {                    //获取原来指定线程的下载记录                    int existDownloadLength = readDownloadInfo(threadid);                    count = count + existDownloadLength;                }                //设置进度条的刻度                pb.setProgress(count);                //计算比率                int result = (count * 100) / filelength;                tv_info.setText("下载:" + result + "%");            } catch (Exception e) {                e.printStackTrace();            }        }        //暂停        pb.setOnLongClickListener(new View.OnLongClickListener() {            @Override            public boolean onLongClick(View view) {                flag = false;                pb.setEnabled(true);                pb.setEnabled(false);                Toast.makeText(MainActivity.this,"暂停",Toast.LENGTH_SHORT).show();                return false;            }        });    }    //下载    public void download(View v){        line1.setVisibility(View.VISIBLE);        flag = true; //是在下载            pb.setEnabled(false);//一点击变成不可点击            pb.setEnabled(true);//一点击变成可点击        new Thread(){//子线程            public void run() {                try {                    //获取服务器上文件的大小                    HttpClient client = new DefaultHttpClient();                    HttpHead request = new HttpHead(uri);                    HttpResponse response = client.execute(request);                    //response  只有响应头  没有响应体                    if(response.getStatusLine().getStatusCode() == 200){                        Header[] headers = response.getHeaders("Content-Length");                        String value = headers[0].getValue();                        //文件大小                        int filelength = Integer.parseInt(value);                        Log.i(TAG, "filelength:"+filelength);                        //设置进度条的最大值                        Message msg_setmax = Message.obtain(mHandler, SET_MAX, filelength, 0);                        msg_setmax.sendToTarget();                        //处理下载记录文件                        for(int threadid=0;threadid<threadsize;threadid++){                            //对应的下载记录文件                            File file = new File(Environment.getExternalStorageDirectory(),threadid+".txt");                            //判断文件是否存在                            if(!file.exists()){                                //创建文件                                file.createNewFile();                            }                        }                        //在sdcard创建和服务器大小一样的文件                        String name = getFileName(uri);                        File file = new File(Environment.getExternalStorageDirectory(),name);                        //随机访问文件                        RandomAccessFile raf = new RandomAccessFile(file, "rwd");                        //设置文件的大小                        raf.setLength(filelength);                        //关闭                        raf.close();                        //计算每条线程的下载量                        int block = (filelength%threadsize == 0)?(filelength/threadsize):(filelength/threadsize+1);                        //开启三条线程执行下载                        for(int threadid=0;threadid<threadsize;threadid++){                            new DownloadThread(threadid, uri, file, block).start();                        }                    }                } catch (Exception e) {                    e.printStackTrace();                }            };        }.start();    }    @Override    public void getUser(ArrayList<Users.NewslistBean> list) {        //加载        if (a==1){            newslistBeen.clear();        }        newslistBeen.addAll(list);        xr.setLayoutManager(new LinearLayoutManager(this));        adapter = new HomeAdapter(list,this);        adapter.setOnItemClickLitener(new OnItemClickLitener() {            @Override            public void onItemClick(View view, int position) {                uri=newslistBeen.get(position).getPicUrl();                Toast.makeText(MainActivity.this,uri,Toast.LENGTH_SHORT).show();            }            @Override            public void onItemLongClick(View view, int position) {                Toast.makeText(MainActivity.this,"长按",Toast.LENGTH_SHORT).show();            }        });        xr.setAdapter(adapter);        //加载        xr.setLoadingListener(new XRecyclerView.LoadingListener() {            @Override            public void onRefresh() {                a=1;                userPresenter = new UserPresenter(MainActivity.this, url);                userPresenter.setNews(Api.Urljson1);                adapter.notifyDataSetChanged();;                xr.refreshComplete();            }            @Override            public void onLoadMore() {                a++;                url="?key=8d6e3228d25298f13af4fc40ce6c9679&num=20&page="+a;                userPresenter = new UserPresenter(MainActivity.this, url);                userPresenter.setNews(Api.Urljson1);                adapter.notifyDataSetChanged();;                xr.loadMoreComplete();            }        });    }    //线程下载类    private class DownloadThread extends Thread{        private int threadid;//线程的id        private String uri;//下载的地址        private File file;//下载文件        private int block;//下载的块        private int start;        private int end;        public DownloadThread(int threadid, String uri, File file, int block) {            super();            this.threadid = threadid;            this.uri = uri;            this.file = file;            this.block = block;            //计算下载的开始位置和结束位置            start = threadid * block;            end = (threadid + 1)*block -1;            try {                //读取该条线程原来的下载记录                int existDownloadLength = readDownloadInfo(threadid);                //修改下载的开始位置   从新下载                start = start + existDownloadLength;            } catch (Exception e) {                e.printStackTrace();            }        }        //下载   状态码：200是普通的下载      206是分段下载        Range:范围        @Override        public void run() {            super.run();            try {                RandomAccessFile raf = new RandomAccessFile(file, "rwd");                //跳转到起始位置                raf.seek(start);                //分段下载                HttpClient client = new DefaultHttpClient();                HttpGet request = new HttpGet(uri);                request.addHeader("Range", "bytes:"+start+"-"+end);//添加请求头                HttpResponse response = client.execute(request);                if(response.getStatusLine().getStatusCode() == 200){                    InputStream inputStream = response.getEntity().getContent();                    //把流写入到文件                    byte[] buffer = new byte[1024];                    int len = 0;                    while((len = inputStream.read(buffer)) != -1){                        //如果暂停下载  点击暂停 false 就直接return 点击下载true接着下载                        if(!flag){                            return;//标准线程结束                        }                        //写数据                        raf.write(buffer, 0, len);                        //读取原来下载的数据量 这里读取是为了更新下载记录                        int existDownloadLength = readDownloadInfo(threadid);//原来下载的数据量                        //计算最新的下载                        int newDownloadLength = existDownloadLength + len;                        //更新下载记录 从新记录最新下载位置                        updateDownloadInfo(threadid, newDownloadLength);                        //更新进度条的显示   下载的百分比                        Message update_msg = Message.obtain(mHandler, UPDATE_VIEW, len, 0);                        update_msg.sendToTarget();                        //模拟  看到进度条动的效果                        SystemClock.sleep(50);                    }                    inputStream.close();                    raf.close();                    Log.i(TAG, "第"+threadid+"条线程下载完成");                }            } catch (Exception e) {                e.printStackTrace();            }        }    }    /**     * 读取指定线程的下载数据量     * @param threadid  线程的id     * @return     * @throws Exception     */    public int readDownloadInfo(int threadid) throws Exception{        //下载记录文件        File file = new File(Environment.getExternalStorageDirectory(),threadid+".txt");        BufferedReader br = new BufferedReader(new FileReader(file));        //读取一行数据        String content = br.readLine();        int downlength = 0;        //如果该文件第一次创建去执行读取操作  文件里面的内容是 null        if(!TextUtils.isEmpty(content)){            downlength = Integer.parseInt(content);        }        //关闭流        br.close();        return downlength;    }    /**     * 更新下载记录     * @param threadid     * @param newDownloadLength     */    public void updateDownloadInfo(int threadid,int newDownloadLength) throws Exception{        //下载记录文件        File file = new File(Environment.getExternalStorageDirectory(),threadid+".txt");        FileWriter fw = new FileWriter(file);        fw.write(newDownloadLength+"");        fw.close();    }    /**     * 获取文件的名称     * @param uri     * @return     */    private String getFileName(String uri){        return uri.substring(uri.lastIndexOf("/")+1);    }}

HomeAdapter类

import android.content.Context;import android.net.Uri;import android.support.v7.widget.RecyclerView;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.TextView;import com.facebook.drawee.backends.pipeline.Fresco;import com.facebook.drawee.interfaces.DraweeController;import com.facebook.drawee.view.SimpleDraweeView;import com.six.zhouerlianxi.R;import com.six.zhouerlianxi.bean.Users;import java.util.List;/** * Created by wangjiao on 2017/11/11. */public class HomeAdapter extends RecyclerView.Adapter<HomeAdapter.MyViewHolder>{    protected static final String TAG = "OtherActivity";    //下载线程的数量    private final static int threadsize = 3;    protected static final int SET_MAX = 0;    public static final int UPDATE_VIEW = 1;    List<Users.NewslistBean> userses;    Context context;    private OnItemClickLitener mOnItemClickLitener;    public void setOnItemClickLitener(OnItemClickLitener mOnItemClickLitener)    {        this.mOnItemClickLitener = mOnItemClickLitener;    }    public HomeAdapter(List<Users.NewslistBean> userses, Context context) {        this.userses = userses;        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 void onBindViewHolder(final MyViewHolder holder, int position)    {        holder.tv.setText(userses.get(position).getTitle());        Uri uri =  Uri.parse(userses.get(position).getPicUrl());        DraweeController controller = Fresco.newDraweeControllerBuilder()                .setUri(uri)                .setAutoPlayAnimations(true)                .build();        holder.image.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;                }            });        }    }    @Override    public int getItemCount()    {        return userses.size();    }    class MyViewHolder extends RecyclerView.ViewHolder    {        TextView tv;        SimpleDraweeView image;        public MyViewHolder(View view)        {            super(view);            tv = view.findViewById(R.id.text);            image = (SimpleDraweeView) view.findViewById(R.id.image);        }    }}

进度条