Android: save and retrieve image to SQLite database

Many people ask how to add the image to SQLite database. Actually, it is every easy.

Here is the process:

1. Get the source: 

  * Save images like JPEG, PNG, WEBP into drawable folder

     Check official: https://developer.android.com/reference/android/graphics/Bitmap.CompressFormat.html

  * Get it from capture. 

2. Convert source to bitmap:

// MyData class holds image data
MyData mDataSample = new MyData();
...
 
// Source is route.png in drawable folder
Bitmap bitmap = ((BitmapDrawable) getDrawable(R.drawable.route)).getBitmap();
 
// Convert bitmap to byte[]. I create a function to do the work
mDataSample.setImageDataFromBitmap(bitmap);

For example, I have a class called MyData, which has function as setImageDataFromBitmap():

public class MyData {
 
    private byte[] imageData = null;
 
...
    // Bitmap to byte[] to imageData
    public void setImageDataFromBitmap(Bitmap image) {
        if (image != null) {
            //bitmap to byte[]
            imageData = bitmapToByte(image);
        } else {
            imageData = null;
        }
    }
 
    // Bitmap to byte[]
    public byte[] bitmapToByte(Bitmap bitmap) {
        try {
            ByteArrayOutputStream stream = new ByteArrayOutputStream();
            //bitmap to byte[] stream
            bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream);
            byte[] x = stream.toByteArray();
            //close stream to save memory
            stream.close();
            return x;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
...

3. Class MyData also converts byte[] to bitmap:

// Convert imageData directly to bitmap
public Bitmap getImageDataInBitmap() {
    if (imageData != null) {
        //turn byte[] to bitmap
        return BitmapFactory.decodeByteArray(imageData, 0, imageData.length);
    }
    return null;
}
 
public byte[] getImageData() {
    return imageData;
}

4. Deal with Database as usually: 

   * create database in YOUR ACTIVITY CLASS:

SQLiteDatabase db = this.openOrCreateDatabase(databaseName, MODE_PRIVATE, null);

  * create table: save image data in BLOB

...
// Keyword I will use
private static final String KEY_IMAGE_DATA = "image_data";
private static final String KEY_RECORD_ID = "record_id";
...
//
String sql = "CREATE TABLE IF NOT EXISTS " + YOUR_TABLE_NAME + "(" +
                ... +
                KEY_IMAGE_DATA + " BLOB, " +
                KEY_RECORD_ID + " INTEGER PRIMARY KEY AUTOINCREMENT )";
db.execSQL(sql);

5. Add record into database:

public void addRecord(... byte[] imageData ...) {
    // Open database
    SQLiteDatabase db = this.getWritableDatabase();
 
    ContentValues values = new ContentValues();
...
    // Column and value of column
    values.put(KEY_IMAGE_DATA, imageData);
...
 
    try {
        newRecordId = db.insertOrThrow(RECORDS_TABLE, null, values);
    } catch (SQLException e) {
        Log.i(TAG, "ERROR: " + e.toString());
    }
    db.close();
}

6. Read record from database:

// Get data from mRecord_id
// MyData is a class hold my image data
public MyData getRecord(int mRecord_id) {
 
    SQLiteDatabase db = this.getReadableDatabase();
 
    String sql = "SELECT * FROM " + RECORDS_TABLE
            + " WHERE " +  KEY_RECORD_ID + " = " + String.valueOf(mRecord_id);
 
    try {
        Cursor cursor = db.rawQuery(sql, null);
 
        MyData x  = new MyData();
 
        // Read data, I simplify cursor in one line
        if (cursor != null) {
            cursor.moveToFirst();
...
            // Get imageData in byte[]. Easy, right?
            x.setImageData( cursor.getBlob( cursor.getColumnIndex(KEY_IMAGE_DATA)) );
...
 
        }
        cursor.close();
        db.close();
        return x;
 
    } catch (SQLException e) {
...
    }
    return null;
}

7. Put your data on screen.

ImageView testImageView = (ImageView) findViewById(R.id.testImageView);
...
 
// Get data from record table where record_id is 0
MyData testData = getRecord(0);
 
Bitmap testImage = testData.getImageDataInBitmap();
 
// Display sample bitmap in YOUR ImageView
testImageView.setImageBitmap(testImage);

The end.