通过服务来下载APK，并在通知栏显示下载进度（两种方式）

可以在启动无绑定的服务前给Intent传布尔型的值，如果是true的话就调用系统的下载服务，否则就用自定义的。

关于服务的更多介绍，请参考我的上一篇博客：Android之四大组件之Service简单总结

关于不使用服务来下载的方法，请参考我之前的博客：下载APk，并在通知栏显示下载进度(两种方式)

代码如下：

private NotificationManager nm;
private NotificationCompat.Builder builder;
private Notification nf;

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.d("====", "服务启动--非绑定方式");
if(intent!=null){
Boolean flag=intent.getBooleanExtra("download", true);
if(flag){
String url="http://10.0.2.2:8080/HttpTest/weixin.apk";
downLoad(url);//调用系统的下载服务
}else{
nm= (NotificationManager) getSystemService(Activity.NOTIFICATION_SERVICE);
builder= new NotificationCompat.Builder(getBaseContext());
String url="http://10.0.2.2:8080/HttpTest/weixin.apk";
new MyDownloadAnsy().execute(url);//自定义notification
}

}
return super.onStartCommand(intent, flags, startId);
}

public void downLoad(String downUrl) {
//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("sdcard/Download/", "test.apk");
request.setNotificationVisibility(DownloadManager.Request.NETWORK_MOBILE | DownloadManager.Request.NETWORK_WIFI);
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
downloadManager.enqueue(request);
}

public class MyDownloadAnsy extends AsyncTask<String,Integer,Integer> {
@Override
protected void onPreExecute() {
super.onPreExecute();
RemoteViews contentView=new RemoteViews(getPackageName(),R.layout.notification_layout);
contentView.setTextViewText(R.id.tv,"测试.apk");
contentView.setProgressBar(R.id.pb,100,0,false);
builder.setContent(contentView).setSmallIcon(R.mipmap.ic_launcher);
nf=builder.build();
nm.notify(0,nf);
}

@Override
protected Integer doInBackground(String... params) {
HttpURLConnection con=null;
InputStream is=null;
OutputStream os=null;
try {
URL url=new URL(params[0]);
con= (HttpURLConnection) url.openConnection();
con.setConnectTimeout(5*1000);  //设置超时时间
if(con.getResponseCode()==200){ //判断是否连接成功
int fileLength = con.getContentLength();
is=con.getInputStream();    //获取输入
os = new FileOutputStream("/sdcard/weixin.apk");
byte[] buffer=new byte[1024*1024*10];
long total=0;
int count;
int pro1=0;
int pro2=0;
while ((count=is.read(buffer))!=-1){
total+=count;
if (fileLength > 0)
pro1=(int) (total * 100 / fileLength);  //传递进度（注意顺序）
if(pro1!=pro2)
publishProgress(pro2=pro1);
os.write(buffer,0,count);
}
}
} 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(con!=null){
con.disconnect();
}
}
return 1;
}

@Override
protected void onPostExecute(Integer result) {
super.onPostExecute(result);

if(result==1){
Toast.makeText(MyService.this, "下载完成", Toast.LENGTH_SHORT).show();
}
}

@Override
protected void onProgressUpdate(Integer... values) {
Log.d("===",""+values[0]);
super.onProgressUpdate(values);
RemoteViews contentView=nf.contentView;
contentView.setProgressBar(R.id.pb,100,values[0],false);
nm.notify(0,nf);
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/weixin.apk"), "application/vnd.android.package-archive");
PendingIntent pendingIntent = PendingIntent.getActivity(getBaseContext(), 0, it, PendingIntent.FLAG_UPDATE_CURRENT);
contentView.setTextViewText(R.id.tv,"下载完成");
builder.setContent(contentView).setContentIntent(pendingIntent);
nf=builder.build();
nm.notify(0,nf);
}
}
}