我有我的应用程序，我正在从 php 站点执行登录功能，我能够完成登录功能。
现在创建用户会话我使用以下代码
sessionmanager.java
public class SessionManager {
// Shared Preferences
SharedPreferences pref;
// Editor for Shared preferences
Editor editor;
// Context
Context _context;
// Shared pref mode
int PRIVATE_MODE = 0;
// Sharedpref file name
private static final String PREF_NAME = "dealnowsp";
// All Shared Preferences Keys
private static final String IS_LOGIN = "IsLoggedIn";
// User name (make variable public to access from outside)
public static final String KEY_NAME = "name";
// Email address (make variable public to access from outside)
public static final String KEY_EMAIL = "email";
// Constructor
public SessionManager(Context context){
this._context = context;
pref = _context.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
editor = pref.edit();
}
/**
* Create login session
* */
public void createLoginSession(String name, String userid){
// Storing login value as TRUE
editor.putBoolean(IS_LOGIN, true);
// Storing email in pref
editor.putString(KEY_EMAIL, userid);
// commit changes
editor.commit();
}
/**
* Check login method wil check user login status
* If false it will redirect user to login page
* Else won't do anything
* */
public void checkLogin(){
// Check login status
if(!this.isLoggedIn()){
Intent i = new Intent(_context, Login.class);
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
//Staring Login Activity
_context.startActivity(i);
}
}
/**
* Get stored session data
* */
public HashMap<String, String> getUserDetails(){
HashMap<String, String> user = new HashMap<String, String>();
// user name
user.put(KEY_NAME, pref.getString(KEY_NAME, null));
// user email id
user.put(KEY_EMAIL, pref.getString(KEY_EMAIL, null));
// return user
return user;
}
/**
* Clear session details
* */
public void logoutUser(){
// Clearing all data from Shared Preferences
editor.clear();
editor.commit();
Intent i = new Intent(_context, MainActivity.class);
// Closing all the Activities
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
// Add new Flag to start new Activity
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
// Staring Login Activity
_context.startActivity(i);
}
/**
* Quick check for login
* **/
// Get Login State
public boolean isLoggedIn(){
return pref.getBoolean(IS_LOGIN, false);
}
}
现在我的登录活动就像
public class Login extends Activity {
Button home,login;
EditText uname,pword;
Context context;
SessionManager session;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
getActionBar().setDisplayHomeAsUpEnabled(true);
uname = (EditText) findViewById(R.id.txtuserid);
pword = (EditText) findViewById(R.id.txtuserpass);
addListenerOnHome();
addListenerOnBtnlogin();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_login, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
NavUtils.navigateUpFromSameTask(this);
return true;
}
return super.onOptionsItemSelected(item);
}
public void addListenerOnHome() {
final Context context = this;
home = (Button)findViewById(R.id.btnhome);
home.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(context,MainActivity.class);
startActivity(intent);
}
});
}
public void addListenerOnBtnlogin() {
context = this;
login = (Button)findViewById(R.id.btnlogin);
login.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
final String username = uname.getText().toString();
final String password = pword.getText().toString();
if(username.trim().length() > 0 && password.trim().length() > 0){
Thread t = new Thread() {
public void run() {
postLoginData(username,password);
}
};
t.start();
}
else{
Toast.makeText(context, "username or password empty", Toast.LENGTH_SHORT).show();
}
}
});
}
private void postLoginData(String username,String password) {
try {
// Create a new HttpClient and Post Header
HttpClient httpclient = new DefaultHttpClient();
Log.e("Response-->", "after httpclient");
HttpPost httppost = new HttpPost("http://10.0.2.2/dealnow/login.php");
Log.e("Response-->", "after httppost");
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("username", username));
nameValuePairs.add(new BasicNameValuePair("password", password));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
Log.e("Responce-->", "after using the list name pair");
// Execute HTTP Post Request
Log.w("SENCIDE", "Execute HTTP Post Request");
HttpResponse response = httpclient.execute(httppost);
Log.e("Responce-->", "after execute the http response");
String str = EntityUtils.toString(response.getEntity(), HTTP.UTF_8);
if (str.toString().equalsIgnoreCase("true")) {
session.createLoginSession("dealnowsp", username); //here is where i am getting NPE even if i declare username variable at class level
runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(context, "Login Successful...!", Toast.LENGTH_SHORT).show();
Intent intent = new Intent(context,MainActivity.class);
startActivity(intent);
}
});
} else {
session.logoutUser();
runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(context, "Incorrect username or password", Toast.LENGTH_SHORT).show();
}
});
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
我的问题是把下面的行放在哪里才能正常工作
session.createLoginSession("dealnowsp", username)