OkHttpClient下载文件

添加权限

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

代码实现

private void ok() {
        OkHttpClient okHttpClient = new OkHttpClient();

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

        okHttpClient.newCall(request).enqueue(new Callback() {

            private int progess;

            @Override
            public void onFailure(Call call, IOException e) {

            }

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

                // 下载 outputStream inputStream
                InputStream inputStream = response.body().byteStream();
                //文件的总长度
                long max = response.body().contentLength();
                String path = Environment.getExternalStorageDirectory() + File.separator + "banmi_330.apk";
                File file = new File(path);

                //当文件不存在，创建出来
                if (!file.exists()) {
                    file.createNewFile();
                }

                FileOutputStream fileOutputStream = new FileOutputStream(file);

                byte[] bytes = new byte[1024];

                int readLength = 0;
                long cureeLength = 0;

                while ((readLength = inputStream.read(bytes)) != -1) {
                    fileOutputStream.write(bytes, 0, readLength);

                    cureeLength += readLength;

                    progess = (int) (cureeLength * 100 / max);
                    progressBar.setProgress(progess);
                    Log.d(TAG, "onResponse: " + progess + "%");
                }

                inputStream.close();
                fileOutputStream.close();
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Toast.makeText(MainActivity.this, "下载成功", Toast.LENGTH_SHORT).show();
                    }
                });
            }
        });
    }

效果图