如何將圖像以BLOB的形式保存到android中的SQLite中，如何從庫中選擇圖像但又不知道如何保存到數據庫中

Question

這是我的代碼：這是我從畫廊中選擇圖像或捕獲圖像的方法。 請告訴我我如何保存它。

     private void selectImage() {
    final CharSequence[] items = { "Take Photo", "Choose from Library", "Cancel" };
    AlertDialog.Builder builder = new AlertDialog.Builder(Enrolement.this);
    builder.setTitle("Add Photo!");
    builder.setItems(items, new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int item) {
            if (items[item].equals("Take Photo")) {
                Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                startActivityForResult(intent, REQUEST_CAMERA);
            } else if (items[item].equals("Choose from Library")) {
                Intent intent = new Intent(
                        Intent.ACTION_PICK,
                        android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
                intent.setType("image/*");
                startActivityForResult(
                        Intent.createChooser(intent, "Select File"),
                        SELECT_FILE);
            } else if (items[item].equals("Cancel")) {
                dialog.dismiss();
            }
        }
    });
    builder.show();
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (resultCode == Activity.RESULT_OK) {
        if (requestCode == SELECT_FILE)
            onSelectFromGalleryResult(data);
        else if (requestCode == REQUEST_CAMERA)
            onCaptureImageResult(data);
    }
}

捕捉

private void onCaptureImageResult(Intent data) {
    Bitmap thumbnail = (Bitmap) data.getExtras().get("data");
    ByteArrayOutputStream bytes = new ByteArrayOutputStream();
    thumbnail.compress(Bitmap.CompressFormat.JPEG, 90, bytes);

    File destination = new File(Environment.getExternalStorageDirectory(),
            System.currentTimeMillis() + ".jpg");

    FileOutputStream fo;
    try {
        destination.createNewFile();
        fo = new FileOutputStream(destination);
        fo.write(bytes.toByteArray());
        fo.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    ivImage.setImageBitmap(thumbnail);
}

對於畫廊，我正在使用此

@SuppressWarnings("deprecation")
private void onSelectFromGalleryResult(Intent data) {
    Uri selectedImageUri = data.getData();
    String[] projection = { MediaStore.MediaColumns.DATA };
    Cursor cursor = managedQuery(selectedImageUri, projection, null, null,
            null);
    int column_index = cursor.getColumnIndexOrThrow(MediaStore.MediaColumns.DATA);
    cursor.moveToFirst();

    String selectedImagePath = cursor.getString(column_index);

    Bitmap bm;
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeFile(selectedImagePath, options);
    final int REQUIRED_SIZE = 200;
    int scale = 1;
    while (options.outWidth / scale / 2 >= REQUIRED_SIZE
            && options.outHeight / scale / 2 >= REQUIRED_SIZE)
        scale *= 2;
    options.inSampleSize = scale;
    options.inJustDecodeBounds = false;
    bm = BitmapFactory.decodeFile(selectedImagePath, options);

    ivImage.setImageBitmap(bm);
}

之后，我想在列表視圖中檢索圖像。 這次，我只能獲取除圖像以外的其他信息。 謝謝

我的數據庫類擴展SQLiteOpenHelper

   public class MyDBHandler extends SQLiteOpenHelper {


private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "employee.db";
public static final String TABLE_EMPLOYEE = "employeeData";
public static final String COLUMN_ID = "id";

public static final String COLUMN_NAME = "name";
public static final String COLUMN_DOB  = "dob";
public static final String COLUMN_ADDRESS = "address";
public static final String COLUMN_OCCUPATION = "Occupation";
//public static final String COLUMN_IMAGE_PATH = "image_path";
public static final String KEY_IMAGE = "image_data";

public MyDBHandler(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {

    db.execSQL("DROP TABLE IF EXISTS TABLE_EMPLOYEE");

    String query = "CREATE TABLE " + TABLE_EMPLOYEE + " ( " +

            COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT , " +
            COLUMN_NAME + " TEXT ," +
            COLUMN_DOB + " TEXT ," +
            COLUMN_ADDRESS + " TEXT ," +
            KEY_IMAGE + "BLOB ," +
            // COLUMN_IMAGE_PATH + " TEXT ," +
            COLUMN_OCCUPATION + " TEXT " +
            ");";

    db.execSQL(query);

}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    db.execSQL("DROP TABLE IF EXISTS" + TABLE_EMPLOYEE);

    onCreate(db);

}

// Add a new row to the databse
public boolean addemplyee(Employee employee) {
    ContentValues values = new ContentValues();
    //values.put(COLUMN_ID, employee.get_id());
    values.put(COLUMN_NAME, employee.get_name());
    values.put(COLUMN_DOB, employee.get_dob());
    values.put(COLUMN_ADDRESS, employee.get_address());
    values.put(COLUMN_OCCUPATION, employee.get_occupation());
    values.put(KEY_IMAGE, employee.get_image());
    //values.put(COLUMN_IMAGE_PATH, employee.get_occupation());

    SQLiteDatabase db = getWritableDatabase();
    Log.i("", "isinsert===" + db.insert(TABLE_EMPLOYEE, null, values));
    db.close();
    return true;
}

public Cursor getAllEmployees() {
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor res = db.rawQuery("SELECT * FROM " + TABLE_EMPLOYEE, null);
    return res;
 }
 }

請檢查一個::

Answer 1

我假設您已經將圖片放入一個字節數組變量中。 要將其作為BLOB存儲在sqlite數據庫中，您需要一個擴展SQLiteOpenHelper的數據庫類。 您將在此類中定義方法以保存和檢索圖像，還創建表和所有其他CRUD操作。 我創建了一個數據庫類供您在項目中使用。 您可以修改以適合您的需求。

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.widget.Toast;


/**
 * Created by Joe Adeoye on 17/11/2015.
 */
public class Database extends SQLiteOpenHelper{
    private static String DATABASE_NAME = "MyDatabase.db";
    private static int DATABASE_VERSION = 1;
    //private SQLiteDatabase mDatabase;
    private Context mContext;
    public Database(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        mContext = context;
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        //initialise database
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
    public boolean isTableExists(String tableName) {
        SQLiteDatabase mDatabase = getReadableDatabase();

        Cursor cursor = mDatabase.rawQuery("select name from sqlite_master where type='table' and name='"+tableName+"'", null);
        if(cursor!=null) {
            if(cursor.getCount()>0) {
                cursor.close();
                return true;
            }
            cursor.close();
        }
        return false;
    }

    private boolean createProfile(){
        SQLiteDatabase mDatabase = getWritableDatabase();

        String sql = "CREATE TABLE tbl_profile (id INTEGER PRIMARY KEY,dp BLOB)";
        try{
            mDatabase.execSQL(sql);
            return true;
        }
        catch(Exception e){
            return false;
        }
    }

    public boolean updateProfileDp(byte[] dp){
        ContentValues values = new ContentValues();
        values.put("dp", dp);
        if(isTableExists("tbl_profile")){
            SQLiteDatabase mDatabase = getWritableDatabase();
            try{
                mDatabase.update("tbl_profile", values, null, null);
                return true;
            }
            catch(Exception e){
                return false;
            }

        }
        else{
            createProfile();
            SQLiteDatabase db = getWritableDatabase();
            long id = db.insert("tbl_profile", null, values);
            if(id  != -1){
                return true;
            }
            else{
                return false;
            }
        }
    }

    public byte[] getProfileDp(){
        String selectQuery = "SELECT * FROM tbl_profile";

        SQLiteDatabase db = getReadableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);

        byte[] result;
        if (cursor.moveToFirst()) {
            result = cursor.getBlob(1);
        }
        cursor.close();
        return result;
    }
}

用法：

Database db = new Database(MyActivity.this);
db.updateProfileDp(myImageBytes); //pass the byte array containing your image here

取回您的圖像：

byte[] myImage = db.getProfileDp(); //you will have your image back

最后，關閉db對象

db.close();

希望能幫助到你

Answer 2

我還注意到您的代碼中有一個小錯誤，這可能會導致無法創建表。 在顯示以下內容的行中查看數據庫類的onCreate方法：

KEY_IMAGE + "BLOB ," +

更改為此：

KEY_IMAGE + " BLOB ," +

只需在第一個雙引號和BLOB關鍵字之間添加一個空格

如果仍然不起作用，請考慮從CREATE TABLE語句中刪除AUTOINCREMENT語句。 由於已將其設置為具有PRIMARY KEY，因此自動遞增將自動應用到它。