Android开发中实现下载文件通知栏显示进度条

android开发中实现下载文件通知栏显示进度条。

1、使用asynctask异步任务实现，调用publishprogress()方法刷新进度来实现（已优化）

public class myasynctask extends asynctask {

    private context context;
    private notificationmanager notificationmanager;
    private notificationcompat.builder builder;

    public myasynctask(context context){
        this.context = context;
        notificationmanager = (notificationmanager) context.getsystemservice(activity.notification_service);
        builder = new notificationcompat.builder(context);
    }

    @override
    protected void onpreexecute() {
        super.onpreexecute();

        builder.setsmallicon(r.mipmap.ic_launcher)
                .setcontentinfo("下载中...")
                .setcontenttitle("正在下载");

    }

    @override
    protected integer doinbackground(string... params) {
        log.e(tag, "doinbackground: "+params[0] );
        inputstream is = null;
        outputstream os = null;
        httpurlconnection connection = null;
        int total_length = 0;
        try {
            url url1 = new url(params[0]);
            connection = (httpurlconnection) url1.openconnection();
            connection.setrequestmethod("get");
            connection.setreadtimeout(50000);
            connection.connect();

            if(connection.getresponsecode() == 200){
                is = connection.getinputstream();
                os = new fileoutputstream("/sdcard/zongzhi.apk");
                byte [] buf = new byte[1024];
                int len;
                int pro1=0;
                int pro2=0;
                // 获取文件流大小，用于更新进度
                long file_length = connection.getcontentlength();
                while((len = is.read(buf))!=-1){
                    total_length += len;
                    if(file_length>0) {
                        pro1 = (int) ((total_length / (float) file_length) * 100);//传递进度（注意顺序）
                    }
                    if(pro1!=pro2) {
                        // 调用update函数，更新进度
                        publishprogress(pro2=pro1);
                    }
                    os.write(buf, 0, len);
                }
            }


        } catch (malformedurlexception e) {
            e.printstacktrace();
        } catch (ioexception e) {
            e.printstacktrace();
        }finally {
            try {
                if (is != null) {
                    is.close();
                }
                if (os != null) {
                    os.close();
                }
            } catch (ioexception e) {
                e.printstacktrace();
            }
            if (connection != null) {
                connection.disconnect();
            }
        }


        return total_length;
    }

    @override
    protected void oncancelled(integer integer) {
        super.oncancelled(integer);
    }

    @override
    protected void oncancelled() {
        super.oncancelled();
    }

    @override
    protected void onprogressupdate(integer... values) {
        super.onprogressupdate(values);
        builder.setprogress(100,values[0],false);
        notificationmanager.notify(0x3,builder.build());
        //下载进度提示
        builder.setcontenttext("下载"+values[0]+"%");
        if(values[0]==100) {    //下载完成后点击安装
            intent it = new intent(intent.action_view);
            it.addflags(intent.flag_activity_new_task);
            it.setdataandtype(uri.parse("file:///sdcard/zongzhi.apk"), "application/vnd.android.package-archive");
            pendingintent pendingintent = pendingintent.getactivity(context, 0, it, pendingintent.flag_update_current);
            builder.setcontenttitle("下载完成")
                    .setcontenttext("点击安装")
                    .setcontentinfo("下载完成")
                    .setcontentintent(pendingintent);
            notificationmanager.notify(0x3, builder.build());
        }
    }

    @override
    protected void onpostexecute(integer integer) {
        super.onpostexecute(integer);
        if(integer == 100) {
            toast.maketext(context, "下载完成", toast.length_short).show();
        }
    }
}

2、使用服务来实现（不是特别推荐此方法）

//取得系统的下载服务
        downloadmanager downloadmanager= (downloadmanager) getsystemservice(context.download_service);
        //创建下载请求对象
        downloadmanager.request request=new downloadmanager.request(uri.parse(downurl));
        request.setdestinationinexternalpublicdir("目录","文件名");
        request.setnotificationvisibility(downloadmanager.request.network_mobile|downloadmanager.request.network_wifi);
        request.setnotificationvisibility(downloadmanager.request.visibility_visible_notify_completed);
        downloadmanager.enqueue(request);