SharedPreferences check if data already exist-CodePudding

i have a problem here, i want to make if same data or value already exists in sharedpreferences it show toast if this data already exist, so i must input other value. i try to check it with contains but everytime i type same value it keeps replacing the same value

this is the code

binding.btnContinue.setOnClickListener  {
        dataExist()
        saveData()
    }
}

private fun saveData() {
    val pref = this.getSharedPreferences(Data.Preferences.PREF_NAME, MODE_PRIVATE)

    val fullName = binding.etFullName.text.toString()
    val jobPref = binding.etJob.text.toString()
    val emailPref = binding.etEmailSignUp.text.toString()
    val passPref = binding.etPassSignUp.text.toString()

    pref.edit {
        putString(Data.Preferences.PREF_FULLNAME, fullName)
        putString(Data.Preferences.PREF_JOB, jobPref)
        putString(Data.Preferences.PREF_EMAIL, emailPref)
        putString(Data.Preferences.PREF_PASS, passPref)
        apply()
    }

    val intent = Intent(this, SignInActivity::class.java)
    startActivity(intent)
}

private fun dataExist(): Boolean {
    val pref = this.getSharedPreferences(Data.Preferences.PREF_NAME, MODE_PRIVATE)

    val checkName = pref.getString(Data.Preferences.PREF_NAME, "")
    val checkJob = pref.getString(Data.Preferences.PREF_JOB, "")

    if (pref.contains(checkName)){
        Toast.makeText(this, "Name already exist", Toast.LENGTH_SHORT).show()
        return true
    }else{
        return false
    }

}

CodePudding user response：

you should check key existence, not value

boolean hasKey = pref.contains(Data.Preferences.PREF_NAME)

and also respect return of dataExist method

if (!dataExist()) saveData() // save only when not exists

edit - working example

if (pref.contains(Data.Preferences.PREF_NAME)){
    val checkName = pref.getString(Data.Preferences.PREF_NAME, null)
    val fullName = binding.etFullName.text.toString()
    // returns true when key exists and value stored under this key
    // is exactly same as entered in EditText
    if (fullName.equals(checkName)) return true
}
return false // no key at all, so no data stored

CodePudding user response：

You are currently calling contains on the value. You need to call contains on the key if you want to ensure whether the key exists or not.

  if (pref.contains(Data.Preferences.PREF_NAME)){
        Toast.makeText(this, "Name already exist", Toast.LENGTH_SHORT).show()
        return true
    }else{
        return false
    }