OKHTTP3.13.1拦截器方式实现文件下载

• 下载进度监听

package com.bliss.yang.myokhttp;

/**
 * @autor YangTianFu
 * @Email ytfunny@126.com
 * @优快云 https://blog.youkuaiyun.com/ytfunnysite
 * @Date 2019/3/5  18:54
 */
public interface ProgressListener {
    public void onProgress(int progress);

    public void onDone(long totalSize);
}

• ResponseBody

package com.bliss.yang.myokhttp;

import java.io.IOException;

import okhttp3.MediaType;
import okhttp3.ResponseBody;
import okio.Buffer;
import okio.BufferedSource;
import okio.ForwardingSource;
import okio.Okio;
import okio.Source;

/**
 * @autor YangTianFu
 * @Email ytfunny@126.com
 * @优快云 https://blog.youkuaiyun.com/ytfunnysite
 * @Date 2019/3/5  18:53
 */
public class ProgressResponseBody extends ResponseBody {

    private ResponseBody mResponseBody;
    private ProgressListener mProgressListener;

    private BufferedSource mBufferedSource;

    public ProgressResponseBody(ResponseBody mResponseBody, ProgressListener mProgressListener) {
        this.mResponseBody = mResponseBody;
        this.mProgressListener = mProgressListener;
    }

    @Override
    public MediaType contentType() {
        return mResponseBody.contentType();
    }

    @Override
    public long contentLength() {
        return mResponseBody.contentLength();
    }

    @Override
    public BufferedSource source() {
        if (mBufferedSource == null) {
            mBufferedSource = Okio.buffer(getsourse(mResponseBody.source()));
        }
        return mBufferedSource;
    }

    private Source getsourse(Source source) {

        return new ForwardingSource(source) {

            long totalSize = 0L;
            long sum = 0L;

            @Override
            public long read(Buffer sink, long byteCount) throws IOException {


                if (totalSize == 0) {
                    totalSize = contentLength();
                }


                long len = super.read(sink, byteCount);

                sum += (len == -1 ? 0 : len);
                int progress = (int) ((sum * 1.0f / totalSize) * 100);

                if (len == -1) {
                    mProgressListener.onDone(totalSize);
                } else {
                    mProgressListener.onProgress(progress);
                }

                return len;
            }
        };


    }
}

• 实现方式

package com.bliss.yang.myokhttp;

import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.Toast;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

import butterknife.BindView;
import butterknife.ButterKnife;
import butterknife.OnClick;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.Interceptor;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public class MainActivity extends AppCompatActivity {

    @BindView(R.id.btn_download)
    Button btnDownload;
    @BindView(R.id.progressBar)
    ProgressBar progressBar;
    public String url = "http://106.12.195.160:8080/music/fcml.mp3";
    public String fileName = "fcml.mp3";
    public static final int EXTERNAL_STORAGE_REQ_CODE = 10;
    private OkHttpClient httpClient;

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

    @OnClick(R.id.btn_download)
    public void onViewClicked() {
        downloadAPK();
    }

    private void initOKhttp() {

//        httpClient = new OkHttpClient();

        httpClient = new OkHttpClient.Builder().addNetworkInterceptor(new Interceptor() {
            @Override
            public Response intercept(Chain chain) throws IOException {
                Response reponse = chain.proceed(chain.request());
                return reponse.newBuilder().body(new ProgressResponseBody(reponse.body(), new Prg())).build();
            }
        }).build();
    }

    class Prg implements ProgressListener {

        @Override
        public void onProgress(final int progress) {
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    progressBar.setProgress(progress);
                }
            });

        }

        @Override
        public void onDone(long totalSize) {

            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    Toast.makeText(MainActivity.this, "下载完成", Toast.LENGTH_LONG).show();
                }
            });
        }
    }

    public void requestPermission() {
        //判断当前Activity是否已经获得了该权限
        if (ContextCompat.checkSelfPermission(this,
                Manifest.permission.WRITE_EXTERNAL_STORAGE)
                != PackageManager.PERMISSION_GRANTED) {

            //如果App的权限申请曾经被用户拒绝过，就需要在这里跟用户做出解释
            if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
                Toast.makeText(this, "please give me the permission", Toast.LENGTH_SHORT).show();
            } else {
                //进行权限请求
                ActivityCompat.requestPermissions(this,
                        new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                        EXTERNAL_STORAGE_REQ_CODE);
            }
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {


        switch (requestCode) {
            case EXTERNAL_STORAGE_REQ_CODE: {
                // 如果请求被拒绝，那么通常grantResults数组为空
                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    //申请成功，进行相应操作

                    Toast.makeText(MainActivity.this, "已获取权限", Toast.LENGTH_LONG).show();
                } else {
                    //申请失败，可以继续向用户解释。
                }
                return;
            }
        }

    }

    private void downloadAPK() {


        Request request = new Request.Builder()
                .url(url)
                .build();

        httpClient.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {

                Log.d("FileDownload", "请求文件出差");

            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                writeFile(response);
            }
        });


    }


    Handler mHandler = new Handler() {


        @Override
        public void handleMessage(Message msg) {


            if (msg.what == 1) {
                int progress = msg.arg1;
                progressBar.setProgress(progress);

            }

        }
    };


    private void writeFile(Response response) {


        InputStream is = null;
        FileOutputStream fos = null;
        is = response.body().byteStream();
        String path = Environment.getExternalStorageDirectory().getAbsolutePath();
        Log.d("FileDownload", "path:" + path);

        File file = new File(path, fileName);
        try {
            fos = new FileOutputStream(file);


            byte[] bytes = new byte[1024];

            int len = 0;

//            long  totalSize = response.body().contentLength();
//
//            long sum =0;

            while ((len = is.read(bytes)) != -1) {


                fos.write(bytes);

//
//                sum +=len;
//
//                int progress = (int) ((sum * 1.0f / totalSize) * 100);
//
//                Message msg = mHandler.obtainMessage(1);
//                msg.arg1 = progress;
//
//                mHandler.sendMessage(msg);


            }


        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {

            try {
                if (is != null) {
                    is.close();
                }

                if (fos != null) {
                    fos.close();
                }
            } catch (IOException e) {
                e.printStackTrace();

            }


        }


    }

}