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.