图像到可绘制的数据库

Question

我有搜索喜和低，阅读许多不同的帖子和教程，但我似乎无法弄清楚如何让我的图像保存在数据库中。

似乎每次我尝试将图像放入数据库时​​，都会导致数据库无法创建，然后我会收到一个强制关闭。我会喜欢一些帮助。

这里是我的代码

package com.ondrovic.boombozzpassport; 

import java.io.ByteArrayOutputStream; 
import java.io.IOException; 

import android.content.ContentValues; 
import android.content.Context; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteOpenHelper; 
import android.graphics.Bitmap; 
import android.graphics.Bitmap.CompressFormat; 
import android.graphics.BitmapFactory; 
import android.provider.BaseColumns; 
import android.util.Log; 

public class Database extends SQLiteOpenHelper implements BaseColumns { 
    private final static String DB_NAME = "boombozz.db"; 
    private final static int DB_VERSION = 1; 
    static final String TABLE_BEERS = "beers"; 
    static final String COL_NAME = "name"; 
    static final String COL_BREWER = "brewer"; 
    static final String COL_ABV = "abv"; 
    static final String COL_RATE = "rating"; 
    static final String COL_BDESC = "breifdescription"; 
    static final String COL_FDESC = "fulldescription"; 
    static final String COL_TYPE = "type"; 
    static final String COL_PIC = "picture"; 

    private Context mContext; 
    private Bitmap picture = null; 

public Database(Context context) { 
    super(context, DB_NAME, null, DB_VERSION); 
} 

@Override 
public void onCreate(SQLiteDatabase db) { 
    db.execSQL("CREATE TABLE beers (" + "_id INTEGER PRIMARY KEY, " 
      + "name TEXT, " + "brewer TEXT, " + "abv REAL, " 
      + "rating REAL, " + "breifdescription TEXT, " 
      + "fulldescription TEXT, " + "type TEXT, " + "picture BLOB);"); 

    addBeer(db, "NAME 1", "BREWER 1", "TYPE 1", "BDESC 1", "FDESC 1", 0, 0, R.drawable.beer1); 

} 

private void addBeer(SQLiteDatabase db, String name, String brewer, 
     String type, String bdesc, String fdesc, int abv, int rate, int image) { 
    final ContentValues cv = new ContentValues(); 
    cv.put(COL_NAME, name); 
    cv.put(COL_BREWER, brewer); 
    cv.put(COL_TYPE, type); 
    cv.put(COL_BDESC, bdesc); 
    cv.put(COL_FDESC, fdesc); 
    cv.put(COL_ABV, abv); 
    cv.put(COL_RATE, rate); 


    final Bitmap bitmap = BitmapFactory.decodeResource(
      mContext.getResources(), image); 
    writeBitmap(cv, COL_PIC, bitmap); 

    db.insert(TABLE_BEERS, null, cv); 
} 

static void writeBitmap(ContentValues cv, String name, Bitmap image) { 
    if (image != null) { 
     try { 
      int size = image.getWidth() * image.getHeight() * 2; 
      ByteArrayOutputStream out = new ByteArrayOutputStream(size); 

      image.compress(CompressFormat.PNG, 100, out); 
      out.flush(); 
      out.close(); 

      cv.put(name, out.toByteArray()); 

     } catch (IOException e) { 

     } 
    } 
} 

@Override 
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
    Log.w("onUpgrade", "Upgrading database from version: " + oldVersion 
      + " to version: " + newVersion); 
    db.execSQL("DROP TABLE IF EXISTS beers"); 
} 
} 

Answer 1

你在下载这些图片吗？如果是，请按照Venkata Krishna的建议将其保存到SD卡/手机存储器中。将图像保存到磁盘非常简单。

首先我们创建一个方法来检查我们是否可以读写外部存储磁盘。

/** 
* @return true if the external storage is mounted or read only. 
*/ 
public static boolean isExternalStorageReadable() { 
    String state = Environment.getExternalStorageState(); 
    return Environment.MEDIA_MOUNTED.equals(state) || Environment.MEDIA_MOUNTED_READ_ONLY.equals(state); 
} 

/** 
* @return true if the external storage is mounted and writable. 
*/ 
public static boolean isExternalStorageWritable() { 
    String state = Environment.getExternalStorageState(); 
    return Environment.MEDIA_MOUNTED.equals(state); 
} 

然后，另一种方法将检查我们是否有足够的可用空间在外部存储磁盘。

/** 
* @return the amount of free space on the external storage. 
*/ 
public static long getAvailableExternalMemorySize() { 
    File path = Environment.getExternalStorageDirectory(); 
    StatFs stat = new StatFs(path.getPath()); 
    long blockSize = stat.getBlockSize(); 
    long availableBlocks = stat.getAvailableBlocks(); 
    return availableBlocks * blockSize; 
} 

现在我们创建一个方法，告诉我们是否可以将文件存储在SD卡中。

/** 
* @return true if the external storage is available, writable, 
* and contains enough free space. 
*/ 
public static boolean isExternalStorageAvailable() { 
    if (!isExternalStorageWritable()) return false; 
    long availableSize = getAvailableExternalMemorySize(); 
    if (availableSize < REQUIRED_STORAGE_SPACE) { 
     return false; 
    } 
    return true; 
} 

哪里REQUIRED_STORAGE_SPACE与空间，你的应用程序将用于存储图像和其他东西的量恒定。

现在我们将创建一个方法来存储图像。

/** 
* @return the File from the given filename. 
*/ 
public static File getImageFile(String filename) { 
    if (!isExternalStorageReadable()) return null; 
    // The images folder path. 
    String imagesFolder = Environment.getExternalStorageDirectory().getPath() 
          + "Android/data/your.app.package/images/"; 
    // Creating the file. 
    File file = new File(imagesFolder + filename);   
    return file; 
} 

/** 
* Write the contents of the HTTP entity to the external 
* storage if available and writable. 
*/ 
public static boolean storeImage(HttpEntity entity, String filename) throws IOException  { 
    if (isExternalStorageAvailable()) { 
     File file = getImageFile(filename); 
     if (file == null) return false; 
     // Write to file output stream. 
     FileOutputStream os = new FileOutputStream(file); 
     entity.writeTo(os); 
     os.close(); 
     return true; 
    } 
    return false; 
} 

把所有的这些方法分为一类，让我们说ImageHelper，检查是否有权限在你的清单文件写入到外部存储，你是好去。

Answer 2

保存在SD卡或手机内存和存储即保存的图像路径database.whenever您要访问的图像，然后从数据库中取图片路径图像，并使用该路径访问图像。