Android 从 Sqlite 数据库保存和获取图像

Posted 2023-02-26

【中文标题】Android 从 Sqlite 数据库保存和获取图像

【英文标题】：Android Save And Get Image From Sqlite Database

【发布时间】：2016-06-25 08:49:00

【问题描述】：

亲爱的 我如何使用 android Studio 保存图像并从 Sqlite 数据库中获取图像？

【问题讨论】：

将图像转换为 Base 64 字符串，然后将其存储到数据库中，反之亦然。请参阅this 了解 android 中的 Base 64 API。

如果要将二进制文件存储到sqlite中，请将其保存为blob类型。也许这个链接可以帮助你：***.com/questions/7331310/…

【参考方案1】：

您可以查看本教程以在 Android 中实现 Sqlite。 http://www.androidhive.info/2011/11/android-sqlite-database-tutorial/

例如，您可以使用这种方式来实现，而不是使用联系人

public class Image
    String imagePath; //it is your absolute image file path

你的DatabaseHandler 可以像下面这样实现

public class DatabaseHandler extends SQLiteOpenHelper 

    // All Static variables
    // Database Version
    private static final int DATABASE_VERSION = 1;

    // Database Name
    private static final String DATABASE_NAME = "imagedb";

    // Contacts table name
    private static final String TABLE_IMAGE = "images";

    // Contacts Table Columns names
    private static final String KEY_ID = "id";
    private static final String KEY_IMAGE_PATH = "name";

    public DatabaseHandler(Context context) 
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    

    // Creating Tables
    @Override
    public void onCreate(SQLiteDatabase db) 
        String sqlQuery = "CREATE TABLE " + TABLE_IMAGE + "("
                + KEY_ID + " INTEGER PRIMARY KEY," + KEY_IMAGE_PATH + " TEXT)";
        db.execSQL(sqlQuery);
    

    // Upgrading database
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) 
        // Drop older table if existed
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_IMAGE);

        // Create tables again
        onCreate(db);
    

    // Adding new image
    public void addImage(Image image) 
        SQLiteDatabase db = this.getWritableDatabase();

        ContentValues values = new ContentValues();
        values.put(KEY_IMAGE_PATH, image.imagePath); // Image path

        // Inserting Row
        db.insert(TABLE_IMAGE, null, values);
        db.close(); // Closing database connection
    


    // Getting single image
    public Image getImage(int id) 
        SQLiteDatabase db = this.getReadableDatabase();

        Cursor cursor = db.query(TABLE_IMAGE, new String[]  KEY_ID,
                        KEY_IMAGE_PATH, KEY_ID + "=?",
                new String[]  String.valueOf(id) , null, null, null, null);
        if (cursor != null)
            cursor.moveToFirst();

        Image image = new Image(Integer.parseInt(cursor.getString(0)),
                cursor.getString(1));
        // return image
        return image;
    

【讨论】：

我认为他想将整个图像对象存储到数据库中，而不是图像路径。

谢谢@ᖷAЯAƸ。我以为他要的是 sqlite 教程。

【参考方案2】：

可能为时已晚。但对未来的读者很有用..

import android.content.Context;
import android.database.Cursor;
import android.database.DatabaseUtils;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteStatement;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;


import java.util.HashMap;

 /**
  * Created by Noorul on 23-05-2016.
 */

@SuppressWarnings("ALL")
public class DBSplash extends SQLiteOpenHelper 

public static final String DATABASE_NAME = "SplashDB.db";
public static final String SPLASH_TABLE_NAME = "splash_db";

private HashMap hp;

public DBSplash(Context context) 
    super(context, DATABASE_NAME, null, 1);


@Override
public void onCreate(SQLiteDatabase db) 
    db.execSQL(
            "create table " + SPLASH_TABLE_NAME + "( name TEXT, image BLOB)"
    );


@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) 
    // TODO Auto-generated method stub
    db.execSQL("DROP TABLE IF EXISTS contacts");
    onCreate(db);


public boolean insertImage(String name, Bitmap img) 
    Bitmap storedBitmap = null;
    String sql = "INSERT INTO " + SPLASH_TABLE_NAME + " (name,image) VALUES(?,?)";
    SQLiteDatabase db = this.getWritableDatabase();
    SQLiteStatement insertStmt = db.compileStatement(sql);

    byte[] imgByte = getBitmapAsByteArray(img);
    try 
        storedBitmap = getImage(name);
     catch (Exception e) 
        AppLog.exception(e);
    
    if (storedBitmap == null) 
        insertStmt.bindString(1, name);
        insertStmt.bindBlob(2, imgByte);
        insertStmt.executeInsert();
        db.close();
    
    return true;



public int numberOfRows() 
    SQLiteDatabase db = this.getReadableDatabase();
    int numRows = (int) DatabaseUtils.queryNumEntries(db, SPLASH_TABLE_NAME);
    return numRows;



public Bitmap getImage(String name) 
    String qu = "SELECT * FROM " + SPLASH_TABLE_NAME;
    Cursor cur = null;
    SQLiteDatabase db = this.getReadableDatabase();

    try 
        cur = db.rawQuery(qu, new String[]);
     catch (Exception e) 
        AppLog.exception(e);
    
    if (cur != null) 
        if (cur.moveToFirst()) 
            int index = cur.getColumnIndexOrThrow("image");
            byte[] imgByte = cur.getBlob(index);
            cur.close();
            return BitmapFactory.decodeByteArray(imgByte, 0, imgByte.length);
        
        if (cur != null && !cur.isClosed()) 
            cur.close();
        
    

    return null;

   public byte[] getBitmapAsByteArray(Bitmap bitmap) 
    ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
    bitmap.compress(Bitmap.CompressFormat.JPEG, 0, outputStream);
    return outputStream.toByteArray();

使用此代码。但是将图像存储在数据库中并不是最佳实践。如果您需要不模糊的图像，请更改图像大小。图像是具有高内存的 blob 类型。移动设备是更小的设备。所以在 sqlite db 中存储许多图像意味着，它会很丑陋。所以使用@thuongle 方法