I have tried many times with different ways but the checkbox to remember the login details is still not working. When I close the app and open the app, it's still in the login activity, even though I checked the remember checkbox before, I don't know where I made an error or am missing another step.

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    btnRegister = (Button) findViewById(R.id.buttonSignup);
    btnRegister.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent i = new Intent(MainActivity.this, RegisterActivity.class);
            startActivity(i);
        }
    });

    sharedPreferences = MainActivity.this.getSharedPreferences("Data", MODE_PRIVATE);
    editor = sharedPreferences.edit();

    boolean login = sharedPreferences.getBoolean("ISLOGGEDIN", false);
    if (login == true){
        edtAccount.setText(sharedPreferences.getString("account",""));
        edtPassword.setText(sharedPreferences.getString("password",""));
        checkBoxRemember.setChecked(true);
    }

    edtAccount = (EditText) findViewById(R.id.editTextAccount);
    edtPassword = (EditText) findViewById(R.id.editTextPassword);
    btnLogin = (Button) findViewById(R.id.buttonLogin);
    checkBoxRemember = (CheckBox) findViewById(R.id.checkBoxRemember);

    db=new Database(this);
    btnLogin.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String account = edtAccount.getText().toString();
            String password = edtPassword.getText().toString();

            if (account.equals("") || password.equals("")){
                Toast.makeText(MainActivity.this,
                        "Không được để trống tài khoản và mật khẩu",
                        Toast.LENGTH_SHORT).show();
            }
            else {
                Boolean result = db.checkUserNamePassword(account, password);
                if(result==true) {
                    if(checkBoxRemember.isChecked()){
                        editor.putBoolean("ISLOGGEDIN",true);
                        Intent intent = new Intent(MainActivity.this, HomeActivity.class);
                        intent.putExtra("account", account);
                        SharedPreferences sharedPref = getSharedPreferences("account", MODE_PRIVATE);
                        SharedPreferences.Editor editor = sharedPref.edit();
                        editor.putString("account", account);
                        editor.putString("password", password);
                        editor.commit();
                        startActivity(intent);
                        MainActivity.this.finish();
                    } else {
                        Intent intent = new Intent(MainActivity.this, HomeActivity.class);
                        intent.putExtra("account", account);
                        SharedPreferences sharedPref = getSharedPreferences("account", MODE_PRIVATE);
                        SharedPreferences.Editor editor = sharedPref.edit();
                        editor.putString("account", account);
                        editor.putString("password", password);
                        editor.putBoolean("ISLOGGEDIN",true);
                        editor.clear();
                        editor.commit();
                        startActivity(intent);
                        MainActivity.this.finish();
                    }
                }
                else{
                    Boolean userCheckResult = db.checkUserName(account);
                    if(userCheckResult == true){
                        Toast.makeText(MainActivity.this,
                                "Sai mật khẩu!", Toast.LENGTH_SHORT).show();
                        edtPassword.setError("invalid password!");
                    } else{
                    Toast.makeText(MainActivity.this,
                        "Account does not exist", Toast.LENGTH_SHORT).show();
                        edtAccount.setError("Tài khoản không tồn tại!");
                    }
                }
            }
        }
    });

}

Or is there a command in the database or elsewhere that affects this?

Edit

Once the user logs in, how can I have them log out again? The following doesn't work:

final AlertDialog.Builder builder = new AlertDialog.Builder(HomeActivity.this);
builder.setMessage(R.string.logout_message);
builder.setNegativeButton("Đăng xuất", new DialogInterface.OnClickListener() {
    @Override
    public void onClick(DialogInterface dialogInterface, int i) {

        Intent intent = new Intent(HomeActivity.this, MainActivity.class);
        startActivity(intent);
       finish();
    }
});

CodePudding user response：

The problem is that you are checking for "ISLOGGEDIN" in this SharedPref

sharedPreferences = getSharedPreferences("Data", MODE_PRIVATE);

but saving your values to this one (with a different name)

SharedPreferences sharedPref = getSharedPreferences("account", MODE_PRIVATE);

A few things to change to fix/clean this up:

• Use the same SharedPreferences database in both places
• Fix the if(login) clause to not use null views and to forward you on to the HomeActivity (as I think you intend)
• Just check if the "account" string is present instead of adding a separate boolean

That would look something like this:

// Just get a single SharedPreferences to use
sharedPreferences = getSharedPreferences("AccountPrefs", MODE_PRIVATE);

// Don't need a separate bool if you can just check the "account" string
String account = sharedPreferences.getString("account","");

if (!account.isEmpty()) {
    Intent intent = new Intent(MainActivity.this, HomeActivity.class);
    intent.putExtra("account", account);       
    startActivity(intent);
    finish();

    // If you don't want to auto-forward to HomeActivity, you could
    // remove the code above and fill in the views here instead. 
    // Just make sure you call findViewById to set them before 
    // this point so they are not null
}

and when you save the logged-in state

Boolean loginIsOk = db.checkUserNamePassword(account, password);
if(loginIsOk) {
    SharedPreferences.Editor editor = sharedPreferences.edit();
    
    if(checkBoxRemember.isChecked()) {
        editor.putString("account", account);
        editor.putString("password", password);
    } else {
        editor.clear();
    }
    
    editor.apply();
    
    Intent intent = new Intent(MainActivity.this, HomeActivity.class);
    intent.putExtra("account", account);
    startActivity(intent);
    finish();
}
else {
    // show toasts
}

To log out (from some other activity like HomeActivity) you would just clear the shared preferences out and launch the login activity, like this

private void logOut() {
    // Clear the prefs
    SharedPreferences prefs = getSharedPreferences("AccountPrefs", MODE_PRIVATE);
    prefs.edit().clear().apply();

    // Use the flags to make sure the
    // user can't press "back" to come back here after logging out
    Intent intent = new Intent(this, MainActivity.class);
    intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | 
                    Intent.FLAG_ACTIVITY_NEW_TASK |
                    Intent.FLAG_ACTIVITY_CLEAR_TASK);
    startActivity(intent);
    finish();
}