在Android中创建存储图像的数据库

Question

我是Android应用程序开发的新手。对于我的一个项目，我需要将图像存储在数据库中。所以这就是我所做的。

package com.img.db; 

import java.io.ByteArrayOutputStream; 

import android.app.Activity; 
import android.content.res.Resources; 
import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 
import android.graphics.drawable.Drawable; 
import android.os.Bundle; 
import android.util.Log; 

public class ImageDb extends Activity { 
/** Called when the activity is first created. */ 
DatabaseHelper dbHelper; 
Bitmap[] images = new Bitmap [3]; 
@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 

    Resources res = this.getResources(); 
    images[0] = BitmapFactory.decodeResource(res,R.drawable.orange); 
    //images[0] = Bitmap.createScaledBitmap(images[0], 70, 70, true) ; 

    ByteArrayOutputStream baos = new ByteArrayOutputStream(); 
    images[0].compress(Bitmap.CompressFormat.PNG, 100, baos); 

    //bm is the bitmap object 

    byte[] b = baos.toByteArray(); 
    String name; 
    name="sample_1"; 
    MyImage img = new MyImage(name,b); 
    dbHelper = new DatabaseHelper(this); 
    dbHelper.AddImage(img); 

    int n = dbHelper.getImageCount(); 
    Log.i("ImageCount","n == "+n); 

} 
} 

和MyImage.java：

package com.img.db; 
import java.io.ByteArrayOutputStream; 
import java.sql.Blob; 

import android.content.Context; 
import android.graphics.Bitmap; 
import android.graphics.Bitmap.CompressFormat; 

public class MyImage { 
int _id; 
String _name; 
byte[] _img; 

public MyImage(String Name,byte[] Img) 
{ 

    this._name=Name; 
    this._img=Img; 
} 

public int getID() 
{ 
    return this._id; 
} 
public void SetID(int ID) 
{ 
    this._id=ID; 
} 

public String getName() 
{ 
    return this._name; 
} 

public byte[] getImg() 
{ 
    return this._img; 
} 

public void setName(String Name) 
{ 
    this._name=Name; 
} 
public void setImg(Bitmap bitmap) 
{ 
    ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); 
    bitmap.compress(CompressFormat.PNG, 0, outputStream); 
    this._img = outputStream.toByteArray(); 
} 
} 

和DatabaseHelper.java为：

package com.img.db; 
import android.content.ContentValues; 
import android.content.Context; 
import android.database.Cursor; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteOpenHelper; 
import android.util.Log; 

public class DatabaseHelper extends SQLiteOpenHelper { 

static final String dbName="imageDB"; 
static final String imgTable="MyImage"; 
static final String colID="ImageID"; 
static final String colName="ImageName"; 
static final String colbytes ="Imagebytes"; 

public DatabaseHelper(Context context) { 
    super(context, dbName, null,33); 

    // TODO Auto-generated constructor stub 
} 

@Override 
public void onCreate(SQLiteDatabase db) { 
    // TODO Auto-generated method stub 
    Log.i("in here", "creating database"); 
    db.execSQL("CREATE TABLE "+ imgTable+" ("+ colID + " INTEGER PRIMARY KEY AUTOINCREMENT, "+ colbytes + "BLOB, " 
      + colName + " TEXT)"); 

    //Inserts pre-defined departments 

} 

@Override 
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
    // TODO Auto-generated method stub 

    db.execSQL("DROP TABLE IF EXISTS "+ imgTable); 
    onCreate(db); 
} 
void AddImage(MyImage img) 
{ 
    Log.i("in here", "adding image");   
    SQLiteDatabase db= this.getWritableDatabase(); 

    if (db==null) 
    { 
     Log.i("nulll", "mnllllsg"); 
    } 
    ContentValues cv=new ContentValues(); 

    cv.put(colName, img.getName()); 
    cv.put(colbytes, img.getImg()); 
    cv.put(colID, 1); 
    db.insert(imgTable, colID, cv); 
    db.close(); 


} 

int getImageCount() 
{ 
    SQLiteDatabase db=this.getWritableDatabase(); 
    Cursor cur= db.rawQuery("Select * from "+imgTable, null); 
    int x= cur.getCount(); 
    cur.close(); 
    return x; 
} 

Cursor getAllImages() 
{ 
    SQLiteDatabase db=this.getWritableDatabase(); 

    //Cursor cur= db.rawQuery("Select "+colID+" as _id , "+colName+", "+colAge+" from "+employeeTable, new String [] {}); 
    Cursor cur= db.rawQuery("SELECT * FROM "+imgTable,null); 
    return cur; 

} 

public int UpdateImg(MyImage img) 
{ 
    SQLiteDatabase db=this.getWritableDatabase(); 
    ContentValues cv=new ContentValues(); 
    cv.put(colName, img.getName()); 
    cv.put(colbytes, img.getImg()); 
    return db.update(imgTable, cv, colID+"=?", new String []{String.valueOf(img.getID())}); 

} 

public void DeleteImg(MyImage img) 
{ 
    SQLiteDatabase db=this.getWritableDatabase(); 
    db.delete(imgTable,colID+"=?", new String [] {String.valueOf(img.getID())}); 
    db.close(); 



} 

} 

错误日志

I/in here ( 635): adding image 
I/SqliteDatabaseCpp( 635): sqlite returned: error code = 1, msg = table MyImage has no column named Imagebytes, db=/data/data/com.img.db/databases/imageDB 
E/SQLiteDatabase( 635): Error inserting ImageName=sample_1 ImageID=1 Imagebytes=[B@406ed320 
E/SQLiteDatabase( 635): android.database.sqlite.SQLiteException: table MyImage has no column named Imagebytes: , while compiling: INSERT INTO MyImage(ImageName,ImageID,Imagebytes) VALUES (?,?,?) 

请指出我的错误代码或给我一些指示，我可以在哪里有些帮助。

任何帮助将是巨大的:)

Answer 1

错误是相当自我explainatory，你想不存在访问列的表：

table MyImage has no column named Imagebytes 

Answer 2

你忘了空白这里

+ colbytes + "BLOB, 

将其更改为

+ colbytes + " BLOB,