Android uses fragment, cannot get fragment internal controls, Findviewbyid () result is null--has been resolved

When you log in to a website, most of the time you submit your login information through a form.
However, sometimes the browser will pop up a login Verification dialog box, for example, this is the use of HTTP Basic authentication.

Let's take a look at the working process of this certification:
The first step: The client sends an HTTP request to the server, and the server verifies that the user has logged in to verify that, if not,
The server returns a 401 unauthozied to the client and adds information to the response header "Www-authenticate".
Such as.

The second step: after receiving the 401 unauthozied, the browser will pop up the Login Verification dialog box. After the user enters the user name and password,
After the browser is encoded with BASE64, it is sent to the server in the authorization header. Such as:

The third step: the server will authorization the header of the user name password out, to verify, if the authentication passes, according to the request, will send resources to the client.

Let's look at a sample Java code:

Import Java.io.ioexception;import Java.io.printwriter;import Javax.servlet.http.httpservlet;import Javax.servlet.http.httpservletrequest;import Javax.servlet.http.httpservletresponse;import Sun.misc.base64decoder;public class Httpauthservlet extends HttpServlet {public void doget (HttpServletRequest request, HttpServletResponse response) throws IOException {string sessionauth = (string) request.getsession (). getattribute (" Auth "), if (Sessionauth! = null) {SYSTEM.OUT.PRINTLN (" This is Next step "), NextStep (request, response);} else {if (! Checkheaderauth (Request, Response)) {Response.setstatus (401); Response.setheader ("Cache-control", "No-store"); Response.setdateheader ("Expires", 0); Response.setheader ("Www-authenticate", "Basic realm=\" test\ "");}} Private Boolean Checkheaderauth (HttpServletRequest request, httpservletresponse response) throws IOException {String Auth = Request.getheader ("Authorization"); SYSTEM.OUT.PRINTLN ("Auth encoded in base64 is" + getFromBASE64 (auth)); if (auth! = null) && (Auth.length () > 6)) {auth = auth.substring (6, Auth.length ()); String Decodedauth = getFromBASE64 (auth); System.out.println ("Auth Decoded from Base64 is" + Decodedauth); Request.getsession () SetAttribute ("Auth", Decodedauth ); return true;} Else{return false;}} private String getFromBASE64 (string s) {if (s = = null) return null; Base64decoder decoder = new Base64decoder (); try {byte[] b = Decoder.decodebuffer (s); return new String (b);} catch (Exceptio N e) {return null;}} public void NextStep (HttpServletRequest request, httpservletresponse response) throws IOException {PrintWriter pw = Respo Nse.getwriter ();p w.println ("When the request arrives at the server for the first time, the server does not have the authenticated information and the server returns a 401 unauthozied to the client.
Certification after the certification information in the session, later in the session period of validity will not be re-certification.