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);