Simple Android Practical Demos: SharedPreferences, SQLite & Camera Example (Java + XML)

SharedPreferences

Save small data (key-value pairs)

SQLite

Store structured data (tables)

Camera

Capture and display image

💾

1 — SharedPreferences (Simple Storage)

Lightweight key-value persistent storage

What it is

SharedPreferences is used to store small data in key-value pairs (like saving settings or simple user data).

Key points

• Data is saved permanently (until app is deleted)
• Very fast and easy to use
• Used for login status, user preferences (theme, language)

How your program works

You type a name in the input box. When you tap Save, the name is stored using a key like "username". When you tap Load, the app reads that value and shows it on screen.

XML — activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="20dp">

    <EditText
        android:id="@+id/editTextName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Enter name"/>

    <Button
        android:id="@+id/btnSave"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Save"/>

    <Button
        android:id="@+id/btnLoad"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Load"/>

    <TextView
        android:id="@+id/textViewResult"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Result"
        android:textSize="18sp"/>

</LinearLayout>

Activity — MainActivity.java

package com.example.sharedprefdemo;

import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    EditText editText;
    Button btnSave, btnLoad;
    TextView textView;

    SharedPreferences sharedPreferences;

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

        editText = findViewById(R.id.editTextName);
        btnSave  = findViewById(R.id.btnSave);
        btnLoad  = findViewById(R.id.btnLoad);
        textView = findViewById(R.id.textViewResult);

        // Create SharedPreferences
        sharedPreferences = getSharedPreferences("MyPrefs", MODE_PRIVATE);

        // Save Data
        btnSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String name = editText.getText().toString();

                SharedPreferences.Editor editor = sharedPreferences.edit();
                editor.putString("username", name);
                editor.apply();

                textView.setText("Saved!");
            }
        });

        // Load Data
        btnLoad.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String savedName = sharedPreferences.getString("username", "No Data");
                textView.setText(savedName);
            }
        });
    }
}

What this demo does: Enter a name → Tap Save → stored in SharedPreferences  |  Tap Load → shows saved name

Key concepts

SharedPreferences

Store small key-value data

putString()

Save data

getString()

Retrieve data

apply()

Save changes

🗄️

2 — SQLite (Database Storage)

Local structured database with rows and columns

What it is

SQLite is a local database inside Android used to store large or structured data (like tables).

Key points

• Stores data in table format (rows & columns)
• Can store multiple records
• Used for user lists, offline apps, notes, contacts, etc.

How your program works

A database and table (users) is created. When you tap Save, the name is inserted into the table. When you tap Load, the app reads data from the table and shows the last saved name.

XML — activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="20dp">

    <EditText
        android:id="@+id/editTextName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Enter name"/>

    <Button
        android:id="@+id/btnSave"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Save to DB"/>

    <Button
        android:id="@+id/btnLoad"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Load from DB"/>

    <TextView
        android:id="@+id/textViewResult"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Result"
        android:textSize="18sp"/>

</LinearLayout>

DBHelper.java

package com.example.sqlitedemo;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DBHelper extends SQLiteOpenHelper {

    public DBHelper(Context context) {
        super(context, "MyDB", null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE users(id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT)");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS users");
        onCreate(db);
    }

    // Insert data
    public void insertData(String name) {
        SQLiteDatabase db = this.getWritableDatabase();
        db.execSQL("INSERT INTO users(name) VALUES('" + name + "')");
    }

    // Get last saved name
    public String getData() {
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery("SELECT * FROM users", null);

        String result = "No Data";
        if (cursor.moveToLast()) {
            result = cursor.getString(1); // name column
        }
        cursor.close();
        return result;
    }
}

Activity — MainActivity.java

package com.example.sqlitedemo;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    EditText editText;
    Button btnSave, btnLoad;
    TextView textView;

    DBHelper dbHelper;

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

        editText  = findViewById(R.id.editTextName);
        btnSave   = findViewById(R.id.btnSave);
        btnLoad   = findViewById(R.id.btnLoad);
        textView  = findViewById(R.id.textViewResult);

        dbHelper = new DBHelper(this);

        // Save to SQLite
        btnSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String name = editText.getText().toString();
                dbHelper.insertData(name);
                textView.setText("Saved to DB!");
            }
        });

        // Load from SQLite
        btnLoad.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String data = dbHelper.getData();
                textView.setText(data);
            }
        });
    }
}

What this demo does: Enter a name → Tap Save to DB → stored in SQLite  |  Tap Load from DB → shows last saved name

Key concepts

SQLiteOpenHelper

Manage database

onCreate()

Create table

execSQL()

Run SQL queries

Cursor

Read data from result

📷

3 — Android Camera Demo

Capture image using Intent and display in ImageView

What it is

This uses Android's camera to take a photo and display it directly inside your app using an ImageView.

Key points

• Uses Intent to open the camera app
• Returns a small image (thumbnail)
• Needs camera permission in the manifest

How your program works

When you tap Open Camera, the camera app opens. After clicking a photo, the image is returned to your app and displayed in the ImageView.

XML — activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="20dp"
    android:gravity="center">

    <Button
        android:id="@+id/btnCamera"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Open Camera"/>

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="300dp"
        android:layout_height="300dp"
        android:layout_marginTop="20dp"
        android:scaleType="centerCrop"/>

</LinearLayout>

Activity — MainActivity.java

package com.example.camerademo;

import android.Manifest;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

import androidx.activity.result.ActivityResultLauncher;
import androidx.activity.result.contract.ActivityResultContracts;
import androidx.appcompat.app.AppCompatActivity;

public class CamActivity extends AppCompatActivity {

    ImageView imageView;
    Button btnCamera;

   
    ActivityResultLauncher cameraLauncher;

 
    ActivityResultLauncher permissionLauncher;

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

        imageView = findViewById(R.id.imageView);
        btnCamera = findViewById(R.id.btnCamera);

     
        cameraLauncher = registerForActivityResult(
                new ActivityResultContracts.TakePicturePreview(),
                bitmap -> {
                    if (bitmap != null) {
                        imageView.setImageBitmap(bitmap);
                    }
                }
        );

        
        permissionLauncher = registerForActivityResult(
                new ActivityResultContracts.RequestPermission(),
                isGranted -> {
                    if (isGranted) {
                        cameraLauncher.launch(null); // open camera
                    } else {
                        Toast.makeText(this, "Camera permission denied", Toast.LENGTH_SHORT).show();
                    }
                }
        );

     
        btnCamera.setOnClickListener(view -> {
            permissionLauncher.launch(Manifest.permission.CAMERA);
        });
    }
}

Add Permission — AndroidManifest.xml

<uses-permission android:name="android.permission.CAMERA"/>

Note: This captures a small thumbnail image (not full-size). Works on most devices without extra setup.

What this demo does: Tap Open Camera → camera opens → capture photo → image shows in ImageView

Key concepts

ACTION_IMAGE_CAPTURE

Open camera via Intent

onActivityResult()

Get captured image

Bitmap

Display image in view

CAMERA permission

Required in manifest