FileDownloader，开源库

https://github.com/lingochamp/FileDownloader

• 特点
• 简单易用
• 单任务多线程/多连接/分块下载(并支持通过ConnectionCountAdapter定制)
• 高并发
• 灵活
• 可选择性支持: 独立/非独立进程
• 自动断点续传

需要注意

当下载的文件大小可能大于1.99GB(2^31-1=2_147_483_647 = 1.99GB)的时候, 请使用FileDownloadLargeFileListener而不是FileDownloadListener(同理使用getLargeFileSofarBytes()
与getLargeFileTotalBytes()

暂停: paused, 恢复: 直接调用start，默认就是断点续传引擎默认会打开避免掉帧的处理(使得在有些情况下回调(FileDownloadListener)不至于太频繁导致ui线程被ddos), 如果你希望关闭这个功能（关闭以后，所有回调会与0.1.9之前的版本一样，所有的回调会立马抛一个消息ui线(Handler)）如果没有特殊需要，直接通过配置filedownloader.properties将process.non-separate置为true，可以有效减少每次回调IPC带来的I/O。

官方演示文档：

Paste_Image.png

实现步骤

权限：

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

1.在项目中引用库:

compile 'com.liulishuo.filedownloader:library:1.6.4'

2.初始化：

FileDownloader.setup(getApplicationContext());

3.下载

final ViewHolder tag;
        final String url;
        boolean isDir = false;
        String path;

        url = "http://cdn.llsapp.com/android/LLS-v4.0-595-20160908-143200.apk";
                tag = new ViewHolder(new WeakReference<>(this), progressBar1, null, speedTv1, 1);
                path = llsApkFilePath;
                tag.setFilenameTv(filenameTv1);
FileDownloader.getImpl().create(url)
                .setPath(path, isDir)
                .setCallbackProgressTimes(300)
                .setMinIntervalUpdateSpeed(400)
                .setTag(tag)
                .setListener(new FileDownloadSampleListener() {

                    @Override
                    protected void pending(BaseDownloadTask task, int soFarBytes, int totalBytes) {
                        super.pending(task, soFarBytes, totalBytes);
                        ((ViewHolder) task.getTag()).updatePending(task);
                    }

                    @Override
                    protected void progress(BaseDownloadTask task, int soFarBytes, int totalBytes) {
                        super.progress(task, soFarBytes, totalBytes);
                        ((ViewHolder) task.getTag()).updateProgress(soFarBytes, totalBytes,
                                task.getSpeed());
                        down_sumber.setText("下載進程： "+soFarBytes/1024/1024+"MB / "+totalBytes/1024/1024+"MB");

                    }

                    @Override
                    protected void error(BaseDownloadTask task, Throwable e) {
                        super.error(task, e);
                        ((ViewHolder) task.getTag()).updateError(e, task.getSpeed());
                    }

                    @Override
                    protected void connected(BaseDownloadTask task, String etag, boolean isContinue, int soFarBytes, int totalBytes) {
                        super.connected(task, etag, isContinue, soFarBytes, totalBytes);
                        ((ViewHolder) task.getTag()).updateConnected(etag, task.getFilename());
                    }

                    @Override
                    protected void paused(BaseDownloadTask task, int soFarBytes, int totalBytes) {
                        super.paused(task, soFarBytes, totalBytes);
                        ((ViewHolder) task.getTag()).updatePaused(task.getSpeed());
                    }

                    @Override
                    protected void completed(BaseDownloadTask task) {
                        super.completed(task);
                        ((ViewHolder) task.getTag()).updateCompleted(task);
                    }

                    @Override
                    protected void warn(BaseDownloadTask task) {
                        super.warn(task);
                        ((ViewHolder) task.getTag()).updateWarn();
                    }
                });
    }

4.ViewHolder的类

private static class ViewHolder {
        private ProgressBar progressBar1;
        private TextView detailTv;
        private TextView speedTv;
        private int position;
        private TextView filenameTv;

        private WeakReference<http_down> weakReferenceContext;

        public ViewHolder(WeakReference<http_down> weakReferenceContext,
                          final ProgressBar progressBar1, final TextView detailTv, final TextView speedTv,
                          final int position) {
            this.weakReferenceContext = weakReferenceContext;
            this.progressBar1 = progressBar1;
            this.detailTv = detailTv;
            this.position = position;
            this.speedTv = speedTv;
        }



        public void setFilenameTv(TextView filenameTv) {
            this.filenameTv = filenameTv;
        }

        private void updateSpeed(int speed) {
            speedTv.setText(String.format("速度：   %dKB/s", speed));
        }

        public void updateProgress(final int sofar, final int total, final int speed) {
            if (total == -1) {
                // chunked transfer encoding data
                progressBar1.setIndeterminate(true);
            } else {
                progressBar1.setMax(total);
                progressBar1.setProgress(sofar);
            }

            updateSpeed(speed);

            if (detailTv != null) {
                detailTv.setText(String.format("sofar: %d total: %d", sofar, total));
            }
        }

        public void updatePending(BaseDownloadTask task) {
            if (filenameTv != null) {
                filenameTv.setText("名稱 ："+task.getFilename());
            }
        }

        public void updatePaused(final int speed) {
            toast(String.format("已停止下載 ", position));
            updateSpeed(speed);
            progressBar1.setIndeterminate(false);
        }

        public void updateConnected(String etag, String filename) {
            if (filenameTv != null) {
                filenameTv.setText("名稱 ："+filename);
            }
        }

        public void updateWarn() {
            toast(String.format("warn %d", position));
            progressBar1.setIndeterminate(false);
        }

        public void updateError(final Throwable ex, final int speed) {
            toast(String.format("error %d %s", position, ex));
            updateSpeed(speed);
            progressBar1.setIndeterminate(false);
            ex.printStackTrace();
        }

        public void updateCompleted(final BaseDownloadTask task) {

            toast(String.format("下載完成，下載路徑 %d %s", position, task.getTargetFilePath()));

            if (detailTv != null) {
                detailTv.setText(String.format("sofar: %d total: %d",
                        task.getSmallFileSoFarBytes(), task.getSmallFileTotalBytes()));
            }

            updateSpeed(task.getSpeed());
//            progressBar1.setIndeterminate(false);
            progressBar1.setMax(task.getSmallFileTotalBytes());
            progressBar1.setProgress(task.getSmallFileSoFarBytes());
        }

        private void toast(final String msg) {
            if (this.weakReferenceContext != null && this.weakReferenceContext.get() != null) {
                Snackbar.make(weakReferenceContext.get().down, msg, Snackbar.LENGTH_LONG).show();
            }
        }

5.停止

FileDownloader.getImpl().pause(downloadId1);

6.删除

new File(llsApkFilePath).delete();
                new File(FileDownloadUtils.getTempPath(llsApkFilePath)).delete();