如何在 SQLite 数据库中存储图像

在我的应用程序中，我正在从图库上传一个图像，我想把这个图像存储在 SQLite 数据库中。如何在数据库中存储位图？我正在将位图转换为字符串并将其保存到数据库中。在从数据库检索它时，我无法将该字符串分配给 ImageView，因为它是一个字符串。

图片上传12.java:

     public class Imageupload12 extends Activity {
Button buttonLoadImage;
ImageView targetImage;
int i = 0;
Database database = new Database(this);
String i1;
String img;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main5);
buttonLoadImage = (Button) findViewById(R.id.loadimage);
targetImage = (ImageView) findViewById(R.id.targetimage);
    

    

Bundle b = getIntent().getExtras();
if (b != null) {
img = b.getString("image");
targetImage2.setImageURI("image");
//i am getting error as i cant assign string to imageview.
    

}
    

buttonLoadImage.setOnClickListener(new Button.OnClickListener() {
    

public void onClick(View arg0) {
// TODO Auto-generated method stub
Intent intent = new Intent(Intent.ACTION_PICK,
android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
Log.i("photo", "" + intent);
startActivityForResult(intent, i);
i = i + 1;
}
});
    

}
    

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    

// TODO Auto-generated method stub
super.onActivityResult(requestCode, resultCode, data);
switch (requestCode) {
    

case 0:
if (resultCode == RESULT_OK) {
Uri targetUri = data.getData();
//             textTargetUri.setText(targetUri.toString());
Bitmap bitmap;
try {
bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(targetUri));
targetImage.setImageBitmap(bitmap);
    

i1 = bitmap.toString();
Log.i("firstimage........", "" + i1);
targetImage.setVisibility(0);
    

SQLiteDatabase db = database.getWritableDatabase();
db.execSQL("INSERT INTO UPLOAD VALUES('" + i1 + "');");
    

} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
break;
    

    

    

}
    

}
}

类别:

    public class Image extends Activity {
Database database = new Database(this);
static EfficientAdapter adapter, adapter1;
static ListView lv1;
    

static SQLiteDatabase db;
static EfficientAdapter adp;
static Cursor c1;
    

static Vector < String > IMAGE = new Vector < String > ();
    

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
    

db = database.getReadableDatabase();
c1 = db.rawQuery("select * from UPLOAD;", null);
    

if (c1.moveToFirst()) {
    

do {
IMAGE.add(c1.getString(0).toString());
    

} while (c1.moveToNext());
    

c1.close();
}
    

lv1 = (ListView) findViewById(R.id.List);
    

adapter = new EfficientAdapter(this);
    

    

lv1.setAdapter(adapter);
    

ImageView add = (ImageView) findViewById(R.id.imv1a);
    

    

    

add.setOnClickListener(new OnClickListener() {
    

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
IMAGE.clear();
    

Intent i = new Intent(Image.this, Imageupload12.class);
startActivity(i);
    

    

}
});
    

    

}
    

    

    

private static class EfficientAdapter extends BaseAdapter {
    

    

//        protected  final Context Context = null;
protected LayoutInflater mLayoutInflater;
AlertDialog.Builder aBuilder;
public EfficientAdapter(Context context) {
// TODO Auto-generated constructor stub
mLayoutInflater = LayoutInflater.from(context);
}
    

@Override
public int getCount() {
// TODO Auto-generated method stub
    

return IMAGE.size();
}
    

@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return position;
}
    

@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
    

@Override
public View getView(final int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
    

final ViewHolder mVHolder;
if (convertView == null) {
convertView = mLayoutInflater.inflate(R.layout.pjtlistdetails, parent, false);
    

mVHolder = new ViewHolder();
    

mVHolder.t1 = (TextView) convertView.findViewById(R.id.pjtdetails);
mVHolder.time = (TextView) convertView.findViewById(R.id.name);
    

    

mVHolder.imv = (ImageButton) convertView.findViewById(R.id.editic);
mVHolder.imvd = (ImageView) convertView.findViewById(R.id.delete);
mVHolder.imvf = (ImageView) convertView.findViewById(R.id.fwd);
    

    

    

    

    

mVHolder.imv.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
    

    

    

String img = IMAGE.elementAt(position);
Log.i("image...", "" + img);
    

Context ctx = v.getContext();
Intent myIntent = new Intent();
ctx = v.getContext();
myIntent.setClass(ctx, Imageupload12.class);
myIntent.putExtra("image", img);
    

ctx.startActivity(myIntent);
    

IMAGE.clear();
    

}
});
static class ViewHolder {
    

ImageButton imv;
ImageView imvd, imvf;
}
}
}
}
}
363218 次浏览
小开

To store any image in sqlite database you need to store that image in byte array instead of string. Convert that image to byte array & store that byte [] to DB. While retrieving that image you will get byte [] convert that byte [] to bitmap by which you will get original image.

小开
最佳答案

You have to use "blob" to store image.

ex: to store a image in to db:

public void insertImg(int id , Bitmap img ) {




byte[] data = getBitmapAsByteArray(img); // this is a function


insertStatement_logo.bindLong(1, id);
insertStatement_logo.bindBlob(2, data);


insertStatement_logo.executeInsert();
insertStatement_logo.clearBindings() ;


}


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

To retrieve a image from db:

public Bitmap getImage(int i){


String qu = "select img  from table where feedid=" + i ;
Cursor cur = db.rawQuery(qu, null);


if (cur.moveToFirst()){
byte[] imgByte = cur.getBlob(0);
cur.close();
return BitmapFactory.decodeByteArray(imgByte, 0, imgByte.length);
}
if (cur != null && !cur.isClosed()) {
cur.close();
}


return null;
}
小开

I believe the best way of storing an image to an SQLLite database is to use the Base 64 algorithm. which converts an image to plain text and back again. You can download the full example Android project at: www.developersfound.com/Base64FromStream.zip. This program does not store the image but it does convert the image from image to text and back again. The Download link above contains the Kotlin code version of below.

Here is the class:

package com.example.TestProject;


import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Base64;
import android.util.Log;


import java.io.*;
import java.net.URL;
import java.net.URLConnection;
import java.nio.channels.FileChannel;


public class Base64CODEC {
private int IO_BUFFER_SIZE = 64;
//private int IO_BUFFER_SIZE = 8192;
private URL urlObject = null;
private URLConnection myConn = null;
ByteArrayOutputStream os = null;


public void Base64CODEC() {}


public Bitmap Base64ImageFromURL(String url) {
Bitmap bitmap = null;
InputStream in = null;
BufferedOutputStream out = null;


try {
urlObject = new URL(url);
myConn = urlObject.openConnection();
in = myConn.getInputStream();


final ByteArrayOutputStream dataStream = new ByteArrayOutputStream();
out = new BufferedOutputStream(dataStream, IO_BUFFER_SIZE);


copyCompletely(in, out);


final byte[] data = dataStream.toByteArray();
BitmapFactory.Options options = new BitmapFactory.Options();


bitmap = BitmapFactory.decodeByteArray(data, 0, data.length, options);
} catch (IOException e) {
Log.e("TAG", "Could not load Bitmap from: " + url);
} finally {
//closeStream(in);
try {
in.close();
} catch (IOException e) {
e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
}
//closeStream(out);
try {
out.close();
} catch (IOException e) {
e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
}
}


return bitmap;
}


private void copyCompletely(InputStream input, OutputStream output) throws IOException {
// if both are file streams, use channel IO
if ((output instanceof FileOutputStream) && (input instanceof FileInputStream)) {
try {
FileChannel target = ((FileOutputStream) output).getChannel();
FileChannel source = ((FileInputStream) input).getChannel();


source.transferTo(0, Integer.MAX_VALUE, target);


source.close();
target.close();


return;
} catch (Exception e) { /* failover to byte stream version */
}
}


byte[] buf = new byte[8192];
while (true) {
int length = input.read(buf);
if (length < 0)
break;
output.write(buf, 0, length);
}


try {
input.close();
} catch (IOException ignore) {
}
try {
output.close();
} catch (IOException ignore) {}
}


public String convertToBase64(Bitmap bitmap) {
ByteArrayOutputStream os = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG,100,os);
byte[] byteArray = os.toByteArray();
return Base64.encodeToString(byteArray, 0);
}


public Bitmap convertToBitmap(String base64String) {
byte[] decodedString = Base64.decode(base64String, Base64.DEFAULT);
Bitmap bitmapResult = BitmapFactory.decodeByteArray(decodedString, 0, decodedString.length);
return bitmapResult;
}


}

And here is the main activity that uses the class:

package com.example.TestProject;


import android.app.Activity;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.ImageView;


public class MainActivity extends Activity implements Runnable {


private Thread thread = null;
private Bitmap bitmap = null;
private Base64CODEC base64CODEC = null;
private ImageView imgViewSource = null;
private ImageView imgViewDestination = null;
private boolean isSourceImageVisible = false;


@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}


public void CmdLoadImage_Click(View view) {
try {
if(isSourceImageVisible == true) {
imgViewSource.setImageBitmap(null);
imgViewDestination.setImageBitmap(null);
isSourceImageVisible = false;
}
else {
base64CODEC = new Base64CODEC();
thread = new Thread(this);
thread.start();
}
}
catch (NullPointerException e) {}


}


public void CmdEncodeImage_Click(View view) {
Base64CODEC base64CODEC = new Base64CODEC();
try {
String base64String = base64CODEC.convertToBase64(bitmap);
imgViewDestination = (ImageView) findViewById(R.id.imgViewDestination);
Bitmap imgViewDestinationBitmap = base64CODEC.convertToBitmap(base64String);
imgViewDestination.setImageBitmap(imgViewDestinationBitmap);
}
catch (NullPointerException e) {
//
}
}


@Override
public void run() {
bitmap = base64CODEC.Base64ImageFromURL("http://developersfound.com/me.png");
handler.sendEmptyMessage(0);
}


private Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
imgViewSource = (ImageView) findViewById(R.id.imgViewSource);
imgViewSource.setImageBitmap(bitmap);
isSourceImageVisible = true;
thread = null;
}
};


}
小开

Use blob to store your image in your sqlite database. Below is an example on how to to use blob.

Setting Up the database

CREATE TABLE " + DB_TABLE + "("+
KEY_NAME + " TEXT," +
KEY_IMAGE + " BLOB);";

Insert in the Database:

public void addEntry( String name, byte[] image) throws SQLiteException{
ContentValues cv = new  ContentValues();
cv.put(KEY_NAME,    name);
cv.put(KEY_IMAGE,   image);
database.insert( DB_TABLE, null, cv );
}

Retrieving data:

 byte[] image = cursor.getBlob(1);

Note:

  1. Before inserting into database, you need to convert your Bitmap image into byte array first then apply it using database query.
  2. When retrieving from database, you certainly have a byte array of image, what you need to do is to convert byte array back to original image. So, you have to make use of BitmapFactory to decode.

Below is an Utility class which I hope could help you:

public class DbBitmapUtility {


// convert from bitmap to byte array
public static byte[] getBytes(Bitmap bitmap) {
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bitmap.compress(CompressFormat.PNG, 0, stream);
return stream.toByteArray();
}


// convert from byte array to bitmap
public static Bitmap getImage(byte[] image) {
return BitmapFactory.decodeByteArray(image, 0, image.length);
}
}
小开

I have two things i need to note. How to store image from gallery and how to store image from uri e.g (www.example.com/myimage.png)

How to store image from gallery

Images are retrieved from gallery inform of Uri data type. Inorder to store images to android SQLite database, you need to convert the image uri to bitmap then to binary characters that is, bytes[] sequence. Then set the table column data type as BLOB data type. After retrieving the images from DB, convert the byte[] data type to bitmap in order to set it to imageview.

how to store image from uri.

Note that you can store images in DB as uri string but only image uri from a website. Convert the uri to string and insert it to your database. Retrieve your image uri as string and convert to uri data type in order to set it to imageview.

You can try this post for worked program and source code how to store images in Sqlite database and display in listview

小开

Don't forget to write user permission code in Manifest file

    protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
CameraActivity = this;


imageView = (ImageView) findViewById(R.id.image_view);
database = new ImageDatabase(this);


//Set OnClick Listener to button view
captureImage = (Button) findViewById(R.id.capture_image);
captureImage.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {




Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(cameraIntent, CAMERA_REQUEST);
}
});




}


@Override
public void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
if (requestCode == CAMERA_REQUEST && resultCode == Activity.RESULT_OK) {


theImage = (Bitmap) data.getExtras().get("data");


ByteArrayOutputStream stream = new ByteArrayOutputStream();
theImage.compress(Bitmap.CompressFormat.PNG, 100, stream);
byte[] byteArray = stream.toByteArray();


SQLiteDatabase db = database.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(ImageDatabase.KEY_IMG_URL, byteArray);
db.insert(ImageDatabase.TABLE_NAME, null, values);
db.close();
Bitmap b = getTheImage();
imageView.setImageBitmap(b);


}
}


public Bitmap getTheImage(){


SQLiteDatabase db = database.getReadableDatabase();
Cursor cursor = (Cursor) db.rawQuery(" SELECT * FROM "+ImageDatabase.TABLE_NAME,null,null);
if (cursor.moveToFirst()){
byte[] imgByte =  cursor.getBlob(cursor.getColumnIndex(ImageDatabase.KEY_IMG_URL));
cursor.close();
return BitmapFactory.decodeByteArray(imgByte,0,imgByte.length);
}
if (cursor != null && !cursor.isClosed()) {
cursor.close();
}


return null;
}
}

DATABASE CLASS

class ImageDatabase extends SQLiteOpenHelper {
public Context context;
public static final String DATABASE_NAME = "dataManager";


public static final int DATABASE_VERSION = 1;
public static final String TABLE_NAME = "data";
public static final String KEY_ID = "id";
public static final String KEY_IMG_URL = "ImgFavourite";


public ImageDatabase(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
this.context = context;
//Toast.makeText(context, "Constructor called", Toast.LENGTH_LONG).show();
}


public static final String CREATE_TABLE = "CREATE TABLE " + TABLE_NAME + "(" + KEY_ID +
" INTEGER PRIMARY KEY AUTOINCREMENT," + KEY_IMG_URL + " BLOB " + ")";
public static final String DROP_TABLE = "DROP TABLE IF EXISTS " + TABLE_NAME + "";


@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_TABLE);
}


@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL(DROP_TABLE);
onCreate(db);
}


public void deleteEntry(long row) {
SQLiteDatabase sqLiteDatabase = getWritableDatabase();
sqLiteDatabase.delete(TABLE_NAME, KEY_ID + "=" + row, null);
}


}

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