OkDownload项目实战

本文介绍项目中引入okhttp-okgo开源框架里的OkDownload部分,实现了RecyclerView列表的下载功能.

引入OKDownload

需求不仅是要支持断点续传,而且还要支持队列下载和任务恢复,这样单单导入okgo的包是不够的,还需要额外导入下面这个okserver的包.然后在APPlication里初始化OkGo

//初始化OkGo
OkGo.getInstance().init(this);
//设置下载路径
OkDownload.getInstance().setFolder(Constants.DOWNLOAD_APK_PATH);

单个任务的下载

上篇博文已经介绍了三个任务下载的基本使用,现在这里直接粘贴代码

  　GetRequest<File> request = OkGo.get(itemsBean.getUrl());

　　DownloadTask task = OkDownload.request(itemsBean.getUrl(), request) .save().register(new ListDownloadListener(itemsBean.getUrl(), mHolder));

　　task.start();

根据下载url得到一个GetRequest对象,然后调用OkDownload的静态方法,把一个保证下载任务唯一性的key(String类型)和这个GetRequest对象传递进去就可以创建一个下载任务了.

列表下载

okdownload库中维护了一个由线程池控制的下载队列,可以通过下面这个方式来设定允许同时下载的任务数目(默认是3个)

OkDownload.getInstance().getThreadPool().setCorePoolSize(2);

然后就是状态控制了,我们都知道一个文件下载伴随有这几种状态

 public static final int NONE = 0;         //无状态

 public static final int WAITING = 1;      //等待

 public static final int LOADING = 2;      //下载中

 public static final int PAUSE = 3;        //暂停

 public static final int ERROR = 4;        //错误

 public static final int FINISH = 5;       //完成

可以根据它提供的一个Progress的status,表示当前状态的字段,来更新UI,给用户反馈.

于是,我们可以获取到当前item的任务之后,让下载的点击事件这样响应:

  Progress progress = task.progress;

            if (progress.status == Progress.LOADING || progress.status == Progress.PAUSE) {

                flikerProgressBar.toggle();

            }

            switch (progress.status) {

                case Progress.PAUSE:

                case Progress.NONE:

                case Progress.ERROR:

                    task.start();

                    break;

                case Progress.LOADING:

                    task.pause();

                    break;

                case Progress.FINISH:

                    if (ApkUtils.isAvailable(context, new File(progress.filePath))) {

                        ApkUtils.startAPP(context, ApkUtils.getPackageName(context, progress.filePath));

                    } else {

                        ApkUtils.install(context, new File(progress.filePath));

                    }

                    break;

            }

            refresh(progress);

判断和获取指定tag的下载任务

  DownloadTask task;

                   
 if (!OkDownload.getInstance().hasTask(itemsBean.getUrl())) {

                        
GetRequest<File> request = OkGo.get(itemsBean.getUrl());

                        
task = OkDownload.request(itemsBean.getUrl(), request)

                                
.save().register(new ListDownloadListener(itemsBean.getUrl(), mHolder));

                   
 } else {

                        
task = OkDownload.getInstance().getTask(itemsBean.getUrl());

                   
 }

如果下载队列里不包含当前tag的任务,通过OkDownload.getInstance().hasTask(String tag)判断,那么就对它新建一个下载任务,因为我们要对他进行下载操作.

如果下载队列里已经包含当前任务,那么我们通过OkDownload.getInstance().getTask(String tag)方法来获取这个task;

然后对这个task进行上面的步骤.

如此,一个下载队列的功能就完成了.

下面贴出完整代码

public class BaseAppsDownloadAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    private List<AppBean.ResultBean.ItemsBean> mList;

    private LayoutInflater inflater;

    private Context context;

    private List<DownloadTask> values;

    private boolean comeFromRank;

    public BaseAppsDownloadAdapter(Context context, List<AppBean.ResultBean.ItemsBean> mList, boolean comeFromRank) {

        this.comeFromRank = comeFromRank;

        this.mList = mList;

        this.context = context;

        inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    }

    public void updateData() {

        //这里是将数据库的数据恢复

        values = OkDownload.restore(DownloadManager.getInstance().getAll());

        notifyDataSetChanged();

    }

    @Override

    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        View view = inflater.inflate(R.layout.home_innovate_item, parent, false);

        return new ViewHolder(view);

    }

    @Override

    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {

        if (mList == null || mList.size() == 0) {

            return;

        }

        AppBean.ResultBean.ItemsBean itemsBean = mList.get(position);

        if (itemsBean == null) {

            return;

        }

        ViewHolder mHolder = (ViewHolder) holder;

        // 判断布局中是否需要显示排行

        if (comeFromRank) {

            mHolder.tv_rank.setVisibility(View.VISIBLE);

            mHolder.tv_rank.setText("" + (position + 1));

        } else {

            mHolder.tv_rank.setVisibility(View.GONE);

        }

        mHolder.bind(mHolder, itemsBean);

        mHolder.flikerProgressBar.setVisibility(View.INVISIBLE);

        mHolder.ib_download.setVisibility(View.VISIBLE);

        if (TextUtils.isEmpty(itemsBean.getUrl())) {

            return;

        }

        if (OkDownload.getInstance().hasTask(itemsBean.getUrl())) {

            DownloadTask task = OkDownload.getInstance().getTask(itemsBean.getUrl()).register(new ListDownloadListener(itemsBean.getUrl(), mHolder));

            mHolder.setTask(task);

            mHolder.setTag(itemsBean.getUrl());

            mHolder.flikerProgressBar.setVisibility(View.VISIBLE);

            mHolder.ib_download.setVisibility(View.INVISIBLE);

            mHolder.refresh(task.progress);

        } else {

            mHolder.flikerProgressBar.setVisibility(View.INVISIBLE);

            mHolder.ib_download.setVisibility(View.VISIBLE);

            mHolder.setTask(null);

            mHolder.setTag(null);

        }

    }

    public void notifySetDataListChanged(List<AppBean.ResultBean.ItemsBean> appsData) {

        mList = appsData;

        notifyDataSetChanged();

    }

    public void unRegister() {

        Map<String, DownloadTask> taskMap = OkDownload.getInstance().getTaskMap();

        for (DownloadTask task : taskMap.values()) {

            task.unRegister(task.progress.tag);

        }

    }

    @Override

    public int getItemCount() {

        return mList == null ? 0 : mList.size();

    }

    public class ViewHolder extends RecyclerView.ViewHolder {

        private final ImageView iv_icon;

        private final TextView tv_name;

        private final TextView tv_size;

        private final TextView tv_rank;

        private final TextView tv_des;

        private final TextView ib_download;

        private FlickerProgressBar flikerProgressBar;

        private DownloadTask task;

        private String tag;

        public ViewHolder(View itemView) {

            super(itemView);

            iv_icon = ((ImageView) itemView.findViewById(R.id.app_icon));

            tv_name = ((TextView) itemView.findViewById(R.id.tv_app_name));

            tv_size = ((TextView) itemView.findViewById(R.id.tv_app_size));

            tv_rank = ((TextView) itemView.findViewById(R.id.tv_app_rank));

            tv_des = ((TextView) itemView.findViewById(R.id.tv_app_des));

            ib_download = ((TextView) itemView.findViewById(R.id.ib_download));

            flikerProgressBar = ((FlickerProgressBar) itemView.findViewById(R.id.btn_progress));

            itemView.setOnClickListener(new View.OnClickListener() {

                @Override

                public void onClick(View v) {

                    context.startActivity(new Intent(context, AppDetailActivity.class)

                            .putExtra("appid", mList.get(getAdapterPosition()).getId())

                            .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK));

                }

            });

        }

        public void setTask(DownloadTask task) {

            this.task = task;

        }

        public void bind(final ViewHolder mHolder, final AppBean.ResultBean.ItemsBean itemsBean) {

            mHolder.tv_name.setText(itemsBean.getName());

            if (TextUtils.isEmpty(itemsBean.getImageUrl())) {

                mHolder.iv_icon.setImageResource(R.mipmap.icon_default);

            } else {

                Glide.with(context).load(itemsBean.getImageUrl()).placeholder(R.mipmap.icon_default).into(mHolder.iv_icon);

            }

            mHolder.tv_des.setText("" + itemsBean.getAbstractString());

            mHolder.tv_size.setText(FileUtil.bytes2kb(itemsBean.getSize()));

            mHolder.flikerProgressBar.setOnClickListener(new View.OnClickListener() {

                @Override

                public void onClick(View v) {

                    if (TextUtils.isEmpty(itemsBean.getUrl())) {

                        Toast.makeText(v.getContext(), "下载链接不存在", Toast.LENGTH_SHORT).show();

                        return;

                    }

                    DownloadTask task;

                    if (!OkDownload.getInstance().hasTask(itemsBean.getUrl())) {

                        GetRequest<File> request = OkGo.get(itemsBean.getUrl());

                        task = OkDownload.request(itemsBean.getUrl(), request)

                                .save().register(new ListDownloadListener(itemsBean.getUrl(), mHolder));

                    } else {

                        task = OkDownload.getInstance().getTask(itemsBean.getUrl());

                    }

                    mHolder.setTask(task);

                    mHolder.setTag(itemsBean.getUrl());

                    mHolder.start();

                }

            });

        }

        public void refresh(Progress progress) {

            flikerProgressBar.setProgress((int) (progress.fraction * 100));

            switch (progress.status) {

                case Progress.NONE:

                    flikerProgressBar.setText("下载");

                    break;

                case Progress.PAUSE:

                    flikerProgressBar.setText("继续");

                    break;

                case Progress.ERROR:

                    flikerProgressBar.setText("出错");

                    break;

                case Progress.WAITING:

                    flikerProgressBar.setText("等待");

                    break;

                case Progress.FINISH:

                    if (ApkUtils.isAppInstalled(context, ApkUtils.getPackageName(context, progress.filePath))) {

                        flikerProgressBar.setText("打开");

                    } else {

                        flikerProgressBar.setText("安装");

                    }

                    break;

                case Progress.LOADING:

                    flikerProgressBar.setText((int) (progress.fraction * 100 + 0.5f) + "%");

                    break;

            }

        }

        public void start() {

            Progress progress = task.progress;

            if (progress.status == Progress.LOADING || progress.status == Progress.PAUSE) {

                flikerProgressBar.toggle();

            }

            switch (progress.status) {

                case Progress.PAUSE:

                case Progress.NONE:

                case Progress.ERROR:

                    task.start();

                    break;

                case Progress.LOADING:

                    task.pause();

                    break;

                case Progress.FINISH:

                    if (ApkUtils.isAvailable(context, new File(progress.filePath))) {

                        ApkUtils.startAPP(context, ApkUtils.getPackageName(context, progress.filePath));

                    } else {

                        ApkUtils.install(context, new File(progress.filePath));

                    }

                    break;

            }

            refresh(progress);

        }

        public void setTag(String tag) {

            this.tag = tag;

        }

        public String getTag() {

            return tag;

        }

    }

    private class ListDownloadListener extends DownloadListener {

        private ViewHolder holder;

        ListDownloadListener(Object tag, ViewHolder holder) {

            super(tag);

            this.holder = holder;

        }

        @Override

        public void onStart(Progress progress) {

        }

        @Override

        public void onProgress(Progress progress) {

            if (tag == holder.getTag()) {

                holder.refresh(progress);

            }

        }

        @Override

        public void onError(Progress progress) {

            Throwable throwable = progress.exception;

            if (throwable != null) throwable.printStackTrace();

        }

        @Override

        public void onFinish(File file, Progress progress) {

            Toast.makeText(context, "下载完成:" + progress.filePath, Toast.LENGTH_SHORT).show();

        }

        @Override

        public void onRemove(Progress progress) {

        }

    }

上面的代码,之所以可以有效的避免RecyclerView滚动item布局混乱的问题.是因为我们对每一个item的各项数据都做了赋值操作.

更新下载进度的ListDownloadListener 只与该任务的tag有关,而tag又是itemBean.getUrl() , 所以只要下载链接唯一,那么这个监听是不会响应到别的iteam上的.

巴特西

OkDownload项目实战

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