i am kind of new to android programming , i am designing a program that has login page and main page.When i sign in for the first time with a username and password, i created a sharedpreferences to remember that username and whenever i enter program , it skips login page and redirects me to main page.What i want to do is, when i press logout button in login page ,i want sharedpreferences forget the value of username in my database(it wont delete it from database) and force me to login me again with the same or different username and password , and i dont want to be redirected to main page when i enter application.I found something like SharedPreferences.Editor.remove() , SharedPreferences.Editor.clear(),commit() ,etc.. But code didnt work.Can you help?
public static class SaveSharedPreference {
static final String PREF_USER_NAME = "username";
static SharedPreferences getSharedPreferences(Context ctx) {
return PreferenceManager.getDefaultSharedPreferences(ctx);
}
public static void setUserName(Context ctx, String userName) {
SharedPreferences.Editor editor = getSharedPreferences(ctx).edit();
editor.putString(PREF_USER_NAME, userName);
editor.commit();
}
public static String getUserName(Context ctx) {
return getSharedPreferences(ctx).getString(PREF_USER_NAME, "");
}
}
Button btnSignIn, btnSignUp;
LoginDataBaseAdapter loginDataBaseAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_uye_kayit_giris);
if (SaveSharedPreference.getUserName(UyeKayitGirisActivity.this).length() == 0) {
Intent i = new Intent(UyeKayitGirisActivity.this, MainActivity.class);
startActivity(i);
// finish();
}
// create a instance of SQLite Database
loginDataBaseAdapter = new LoginDataBaseAdapter(this);
loginDataBaseAdapter = loginDataBaseAdapter.open();
// Get The Refference Of Buttons
btnSignIn = (Button) findViewById(R.id.buttonSignIN);
btnSignUp = (Button) findViewById(R.id.buttonSignUP);
// Set OnClick Listener on SignUp button
btnSignUp.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
/// Create Intent for SignUpActivity abd Start The Activity
Intent intentSignUP = new Intent(getApplicationContext(), SignUPActivity.class);
startActivity(intentSignUP);
}
});
Button btn_exit;
// super.onCreate(savedInstanceState);
// setContentView(R.layout.main1);
btn_exit = (Button) findViewById(R.id.buttonLogOUT);
btn_exit.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// WHAT SHOULD I WRITE IN HERE?????????????
Toast.makeText(UyeKayitGirisActivity.this, "ÜYE GİRİŞİ TEKRAR ZORUNLU HALE GETİRİLDİ!!!", Toast.LENGTH_LONG).show();
}
});
}
Try like this
SharedPreferences pref = mContext.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
Editor editor = pref.edit();
editor.clear();
editor.commit();
Here is the Method
private void removePreference(Context context, String prefsName, String key) {
SharedPreferences preferences = context.getSharedPreferences(prefsName, Activity.MODE_PRIVATE);
android.content.SharedPreferences.Editor editor = preferences.edit();
editor.remove(key);
editor.apply();
}
You can call it like:
public void removeUser() {
removePreference(context, FILENAME, KEY_USER);
}
Since you have mentioned that you do NOT want to delete the value of login from shared preference but only ask for login page each time, I believe you are looking for something where you want to clear application cache programatically.
Please check, Clear Cache in Android Application programmatically and Clear Application's Data Programmatically
It is also worth reading this wonderful answer - Don't delete database or shared Preference on clear app
To remove them all SharedPreferences.Editor.clear() followed by a commit()
Related
public class LoginActivity extends BaseActivity{
private SharedPreferences pref;
private SharedPreferences.Editor editor;
private EditText accountEdit;
private EditText passwordEdit;
private Button login;
private CheckBox rememberPass;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
accountEdit =(EditText)findViewById(R.id.account);
passwordEdit = (EditText)findViewById(R.id.password);
rememberPass=(CheckBox)findViewById(R.id.remember_pass);
login = (Button)findViewById(R.id.login);
editor.putBoolean("remember_password",false);
boolean isRemember = pref.getBoolean("remember_password",false);
if(isRemember){
String account = pref.getString("account", "");
String password =pref.getString("password", "");
accountEdit.setText(account);
passwordEdit.setText(password);
rememberPass.setChecked(true);
}
login.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
String account =accountEdit.getText().toString();
String password = passwordEdit.getText().toString();
if (account.equals("admin")&& password.equals("123456"))
{ editor = pref.edit();
if(rememberPass.isChecked())
{
editor.putBoolean("remember_password",true);
editor.putString("account",account);
editor.putString("password",password);
}
else
{
editor.clear();
}
editor.commit();
Intent intent = new Intent(LoginActivity.this,MainActivity.class);
startActivity(intent);
finish();
}
else
{
Toast.makeText(LoginActivity.this,"account for password is invalid",
Toast.LENGTH_LONG).show();
}
}
});
}
}
I use Eclipse to code android.I got an error in LogCat,which is NullPointerException cause by "boolean isRemember = pref.getBoolean("remember_password",false);"
I don't know why.How to use getBoolean correctly?
Thanks in advance.
Because pref=null at
boolean isRemember = pref.getBoolean("remember_password",false);
initialized it before used
SharedPreferences pref= PreferenceManager.getDefaultSharedPreferences(LoginActivity.this);
You have to create the object of the Shared preference than you can use it in yours code
SharedPreferences prefs = getSharedPreferences(MY_PREFS_NAME, MODE_PRIVATE);
than use
boolean isRemember = pref.getBoolean("remember_password",false);
Use this simple way to use prefrences
private SharedPreferences getPrefs;
//in OnCreate
getPrefs = PreferenceManager.getDefaultSharedPreferences(Activity_Name.this);
//At insertion value
getPrefs.edit().putBoolean("Key_Name", false).commit();
//At fetching Values
boolean a = getPrefs.getBoolean("Key_Name", false);
I have a single string which the user will edit and will be displayed back to him when he uses the app. He can edit the string at any time. I am familiar with SQLite databases, but because for this purpose I am using only one string/one record, I felt SharedPreferences would be better. However, after following two different tutorials, I am unable to get it so save the data. In both cases I have needed to amend the tutorial code because I will be using two activities, one to view the code, the other to edit it. I was unable to find a tutorial for using sharedpreferences for two activities. Below is the code.
Class to view the code:
public class MissionOverviewActivity extends Activity {
TextView textSavedMem1;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mission_view);
textSavedMem1 = (TextView)findViewById(R.id.textSavedMem1);
LoadPreferences();
textSavedMem1.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
finish();
return;
}});
};
private void LoadPreferences(){
SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
String strSavedMem1 = sharedPreferences.getString("MEM1", "");
textSavedMem1.setText(strSavedMem1);
}
}
Class to edit the code and return to the view page
public class MissionDetailActivity extends Activity {
EditText editText1;
Button buttonSaveMem1;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mission_edit);
editText1 = (EditText)findViewById(R.id.editText1);
buttonSaveMem1 = (Button)findViewById(R.id.buttonSaveMem1);
buttonSaveMem1.setOnClickListener(buttonSaveMem1OnClickListener);
}
Button.OnClickListener buttonSaveMem1OnClickListener
= new Button.OnClickListener(){
#Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
SavePreferences("MEM1", editText1.getText().toString());
viewStatement();
}
};
private void SavePreferences(String key, String value){
SharedPreferences sharedPreferences = getPreferences(MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString(key, value);
editor.commit();
}
protected void viewStatement() {
Intent i = new Intent(this, MissionOverviewActivity.class);
startActivity(i);
}
}
If any body could answer this question, or point me in the direction of a sharedpreferences tutorial that uses two classes (for edit and displaying), It would be greatly appreciated!
Thanks
getPreferences(int) is private for Activity, you want to share the same SharedPreference between activities you should use this way:
SharedPreferences prefs = this.getSharedPreferences(
"yourfilename", Context.MODE_PRIVATE);
and use the same method when you want to reload it. here the doc for getPrerences(int)
I want to create a simple app to upload my location .I have two activities and in first activity the user can input parameters url for upload with editbox , a checkbox if user wish upload location save preferences button and start button for go to get location activity.I try this but no work...How i call my function start and save?Any help?I have errors when debug...after click button
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
SharedPreferences preferences = getSharedPreferences("gpstracker" , MODE_PRIVATE);
String strValue = preferences.getString("Url",strValued);
edittxtUrl = (EditText)findViewById(R.id.txtUrl);
edittxtUrl.setText(strValue);
Button buttonStart = (Button)findViewById(R.id.buttonStart);
buttonStart.setOnClickListener(startListener);
Button buttonSave = (Button)findViewById(R.id.buttonSave);
buttonSave.setOnClickListener(saveListener);
}
private OnClickListener startListener = new OnClickListener() {
public void onClick(View v) {
Start();
}
};
private OnClickListener saveListener = new OnClickListener() {
public void onClick(View v) {
Save();
}
};
public void Save() {
SharedPreferences preferences = getSharedPreferences("gpstracker" , MODE_PRIVATE);
SharedPreferences.Editor editor = preferences.edit();
edittxtUrl = (EditText)findViewById(R.id.txtUrl);
String strUrl = edittxtUrl.getText().toString();
CheckBox chkTandC = (CheckBox)findViewById(R.id.chkTandC);
boolean blnTandC = chkTandC.isChecked();
editor.putString("Url", strUrl); // value to store
editor.putBoolean("TandC", blnTandC); // value to store
// Commit to storage
editor.commit();
}
public void Start() {
startActivity(new Intent(this, LocTracker.class));
}
Without your log cat it is somewhat hard to tell what your problem is, but what I think is happening is that you are passing a null view to the start method, and this is a problem because you are then trying to get a context. Effectively what you have written is
null.getContext()
which doesn't work. You can fix this by replacing view.getContext() with getApplicationContext()
I decided to use sharedPreferences so I could store the value of a togglebutton on my activity Preferences. On my main activity I want to hide a twitter button when the user clicks the twitter button in the Preferences activity.
private SharedPreferences prefs;
private String prefName = "MyPref";
private ToggleButton timer, twitter;
// this is the key used to set the timer to visible or hidden
private static final String TIMER_KEY = "timekey";
private static final String TWITTER_KEY= "tweet";
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.preferences);
timer = (ToggleButton)findViewById(R.id.timer_pref);
twitter =(ToggleButton)findViewById(R.id.twitter_pref);
timer.setChecked(true);
twitter.setChecked(true);
// Toast.makeText(Preferences.this, timer, Toast.LENGTH_SHORT).show();
Button b = (Button) findViewById(R.id.home_btn);
b.setOnClickListener(new View.OnClickListener()
{
// now add the new screen
public void onClick(View arg0) {
// TODO Auto-generated method stub
// get the shared perference data
Intent i = new Intent(Preferences.this, AndroidGUIActivity.class);
startActivity(i);
}
});
twitter.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
prefs = getSharedPreferences("MyPref", 0 );
SharedPreferences.Editor editor = prefs.edit();
if (timer.isChecked() == true)
{
editor.putBoolean("twitterButtonStatus", true);
}
else if(timer.isChecked() == false)
{
editor.putBoolean("twitterButtonStatus", false);
}
// now save the value that is passed to the editor.putBoolean function
// the twitter data hase been saved
editor.commit();
// now store the variable so that it can be copied to another activity
Bundle b = new Bundle();
}
});
There is no need to transfer Preferences through activities using intent.
You can access your "shared"Preferences from any activity.
You just put the button status with a string key inside:
SharedPreferences settings = getSharedPreferences("MyPrefs", 0);
SharedPreferences.Editor editor = settings.edit();
editor.putBoolean("twitterButtonStatus", buttonStatus);
And in another activity you retrieve these preferences using string key ("twitterButtonStatus"):
SharedPreferences settings = getSharedPreferences("MyPrefs", 0);
boolean buttonStatus = settings.getBoolean("twitterButtonStatus", false); // second param is default!
See: http://developer.android.com/guide/topics/data/data-storage.html
Edit:
Youre saving SharedPrefs now, to get them back and set your Button Gone do something like this:
SharedPreferences settings = getSharedPreferences(prefName, 0);
boolean buttonStatus = settings.getBoolean(TWITTER_KEY, true); //2nd is default
if(buttonstatus==false) twitter.setVisibility(View.GONE);
i have create login page with 2 EditText and checkbox and login button.
if i set checkbox to Enabled i want to save data so next time user doesn't need to fill that fields..
i have uses this code but no luck..
public class LoginPage extends Activity {
EditText d_ID;
EditText password;
CheckBox cb;
ImageButton ib;
public static final String PREFS_NAME = "MyPrefsFile";
public String PREFS_USER;
public String PREFS__PASS;
String username;
String upass;
SharedPreferences pref
#Override
public void onCreate(Bundle savedInstanceState) {
requestWindowFeature(Window.FEATURE_NO_TITLE);
super.onCreate(savedInstanceState);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
setContentView(R.layout.loginpage);
d_ID = (EditText) findViewById(R.id.dulzuID);
password = (EditText) findViewById(R.id.dulzuPASS);
cb = (CheckBox) findViewById(R.id.remember);
ib = (ImageButton) findViewById(R.id.login);
pref = getSharedPreferences(PREFS_NAME, MODE_PRIVATE);
username = pref.getString(PREFS_USER, null);
upass = pref.getString(PREFS__PASS, null);
d_ID.setText(username);
password.setText(upass);
ib.setOnClickListener(new OnClickListener() {
public void onClick(View view) {
startActivity(new Intent(LoginPage.this, Features.class));
}
});
cb.setOnCheckedChangeListener(new OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton cb1, boolean bln) {
PREFS_USER = d_ID.getText().toString();//get user name from EditText
PREFS__PASS = password.getText().toString();//get user Password from EditText
getSharedPreferences(PREFS_NAME, MODE_PRIVATE).edit().putString(PREFS_USER, username).putString(PREFS__PASS, upass).commit();
}
});
}
}
Any help??
Thanks...
I think you are confusing the variables for retrieving the value of the users password and the variables that identify the username/password values in the preferences. I think that you intend these:
public String PREFS_USER;
public String PREFS__PASS;
to be the identifiers for your stored username and password, however you then set them to be the values that you have pulled from the corresponding EditTexts. I have rewritten some of the code for you:
public static final String PREFS_NAME = "MyPrefsFile";
public static final String PREFS_USER = "prefsUsername";
public static final String PREFS__PASS = "prefsPassword";
...
pref = getSharedPreferences(PREFS_NAME, MODE_PRIVATE);
username = pref.getString(PREFS_USER, "");
upass = pref.getString(PREFS__PASS, "");
...
public void onCheckedChanged(CompoundButton cb1, boolean bln) {
username = d_ID.getText().toString();//get user name from EditText
upass = password.getText().toString();//get user Password from EditText
getSharedPreferences(PREFS_NAME, MODE_PRIVATE).edit().putString(PREFS_USER, username).putString(PREFS__PASS, upass).commit();
}
Personally, I wouldn't do it like that though. I would check the value of the checkbox when the user submits the form, and only save the username & password at that point. What if the user unchecks and then rechecks the tick box before they have entered their password? You will save empty values and annoy your users.
You are doing small mistake in this part:
if (cb.isChecked()) {
SharedPreferences pref = getSharedPreferences(PREFS_NAME, MODE_PRIVATE);
username = pref.getString(PREFS_USER, null);
upass = pref.getString(PREFS__PASS, null);
d_ID.setText(username);
password.setText(upass);
}
As your view is rendered each time when new activity starts.cb.isEnabled() will always give false because it is not enabled that time.
You can do stuff for your sol like this.
SharedPreferences pref = getSharedPreferences(PREFS_NAME, MODE_PRIVATE);
if(!pref.getstring(PREFS_USER,null).equals(null)||!pref.getstring(PREFS_USER,null).equals(""))
{username = pref.getString(PREFS_USER, null);
d_ID.setText(username);}
and same for password field
One thing that I would like to tell you: do not store the values when user clicks on check box save it when user presses login button.
If user clicked that check box when he has not entered details the you will save null values.
And why don't you serialize both the objects and save it to memory and again deserialize it when you need to read it?
public void serializeCredentials(String Username,String Password) {
try {
FileOutputStream fStream = openFileOutput(namefile.bin, Context.MODE_PRIVATE) ;
ObjectOutputStream oStream = new ObjectOutputStream(fStream);
oStream.writeObject(Username) ;
FileOutputStream fos = openFileOutput(passwordfile.bin, Context.MODE_PRIVATE) ;
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(Password) ;
oStream.flush() ;
oStream.close() ;
oos.flush() ;
oos.close() ;
Log.v("Serialization success", "Success");
} catch (Exception e) {
Log.v("IO Exception", e.getMessage());
}
}
Don't forget to deserialize when reading data; you can deserialize it similarly.
I think you need to write/initialize this line inside onCreate() method.
SharedPreferences pref;
#Override
public void onCreate(Bundle savedInstanceState) {
requestWindowFeature(Window.FEATURE_NO_TITLE);
super.onCreate(savedInstanceState);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
setContentView(R.layout.loginpage);
pref = getSharedPreferences(PREFS_NAME, MODE_PRIVATE);
...
}
try doing the editing line by line.. at least in my case, it did the trick..
cb.setOnCheckedChangeListener(new OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton cb1, boolean bln) {
PREFS_USER = d_ID.getText().toString();//get user name from EditText
PREFS__PASS = password.getText().toString();//get user Password from EditText
SharedPreferences.Editor prefEditor = getSharedPreferences(PREFS_NAME, MODE_PRIVATE).edit();
prefEditor.putString(PREFS_USER, username);
prefEditor.putString(PREFS__PASS, upass);
prefEditor.commit();
}
});
And it would be much better if you follow N-JOY's suggestion to trigger saving data to SharedPreferences during login button click..