SharedPreferences | Android Studio | Kotlin

SharedPreferences | Android Studio | Kotlin

SharedPreferences is one of the types of saving data in Android Devices. You can save String, int, boolean, long, float, and Set<String>  types of data in SharedPreferences. In SharedPreferences data is saved in the key-value form. If you have a relatively small collection of key-values that you'd like to save, then you should use the SharedPreferences APIs. You can Add, Edit/Modify and Remove data from the SharedPreferences easily.

To get the access to the preferences, we have the three APIs to choose from:

getPreferences() : used from within your Activity, to access the activity-specific preferences.
getSharedPreferences() : used from within your Activity (or other application Context), to access the application-level preferences.
getDefaultSharedPreferences() : used on the PreferenceManager, to get the shared preferences that work in concert with Android’s overall preference framework.

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SharedPreferences | Android Studio | Kotlin

Step 1: Create a new project or open an existing project

Step 2: Code

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="10dp"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/nameEt"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Name"
        android:inputType="textPersonName|textCapWords" />

    <EditText
        android:id="@+id/ageEt"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Age"
        android:inputType="date" />

    <EditText
        android:id="@+id/emailEt"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Email"
        android:inputType="textEmailAddress" />

    <EditText
        android:id="@+id/passwordEt"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Password"
        android:inputType="textPassword" />

    <CheckBox
        android:id="@+id/rememberCb"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Remember" />

    <Button
        android:id="@+id/saveBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:text="Save" />

</LinearLayout>

MainActivity.kt

package com.blogspot.atifsoftwares.myapplication

import android.content.Context
import android.content.SharedPreferences
import android.os.Bundle
import android.view.View
import android.widget.Button
import android.widget.CheckBox
import android.widget.EditText
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {
    //variables
    var name: String? = null
    var email: String? = null
    var password: String? = null
    var age = 0
    var isRemembered = false

    //shared pref
    lateinit var sharedPreferences: SharedPreferences
    lateinit var spEditor: SharedPreferences.Editor

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        //init share pref
        sharedPreferences = getSharedPreferences("USER_INFO_SP", Context.MODE_PRIVATE)

        //get data from shared preferences
        name = sharedPreferences.getString("NAME", "")
        age = sharedPreferences.getInt("AGE", 0)
        email = sharedPreferences.getString("EMAIL", "")
        password = sharedPreferences.getString("PASSWORD", "")
        isRemembered = sharedPreferences.getBoolean("REMEMBER", false)

        //set data to views
        nameEt.setText(name)
        ageEt.setText("" + age)
        emailEt.setText(email)
        passwordEt.setText(password)
        rememberCb.setChecked(isRemembered)

        //click to input data from views
        saveBtn.setOnClickListener(View.OnClickListener {
            //get data from views
            name = "" + nameEt.getText().toString().trim()
            age = ageEt.getText().toString().trim().toInt()
            email = "" + emailEt.getText().toString().trim()
            password = "" + passwordEt.getText().toString().trim()
            if (rememberCb.isChecked()) {
                isRemembered = true
                //save data to shared preferences
                spEditor = sharedPreferences.edit()
                spEditor.putString("NAME", name)
                spEditor.putInt("AGE", age)
                spEditor.putString("EMAIL", email)
                spEditor.putString("PASSWORD", password)
                spEditor.putBoolean("REMEMBER", true)
                spEditor.apply()
                Toast.makeText(this@MainActivity, "Info is remembered...", Toast.LENGTH_SHORT).show()
            } else {
                isRemembered = false
                //don't save | remove data from shared preferences
                spEditor = sharedPreferences.edit()
                spEditor.clear()
                spEditor.apply()
                Toast.makeText(this@MainActivity, "Info is not remembered...", Toast.LENGTH_SHORT).show()
            }
        })
    }
}

Step 3: Run Project

Output