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我正在尝试将我的 SQLite 数据库中的数据显示到回收站视图。我要显示的数据是图像和文本。对于我数据库中的图像，我将图像资源转换为位图，然后转换为字节并将字节存储在我的 Blob 列中。但是，当我尝试使用从列中检索字节时，getBlob()我收到一个异常。

例外是android.database.sqlite.SQLiteException: unknown error (code 0 SQLITE_OK): INTEGER data in nativeGetBlob。我知道发生此异常是因为getBlob()从我的 Blob 列中检索 Integer 数据。但我不明白我将字节放入 Blob 列，那么为什么要getBlob()检索 Integer 数据？

我尝试过使用，getInt()但这不起作用，因为我的适配器使用BitmapFactory.decodeByteArray()期望字节参数将字节从我的列转换为位图。

SQLite 数据库：

package com.myapps.myapplication;

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.BitmapFactory;
import android.util.Log;

import java.io.ByteArrayOutputStream;
import java.util.ArrayList;

public class MyDatabaseHelper extends SQLiteOpenHelper {

private static final String DB_NAME = "starbuzz";
private static final int DB_VERSION = 6;
private Context context;
private ArrayList <Bitmap> bitmapArray;
private byte [] byteArray;

public MyDatabaseHelper(Context context) {
    super(context, DB_NAME, null, DB_VERSION);
    this.context = context;
}

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL("CREATE TABLE GROCERY_ITEMS (" + "_id INTEGER PRIMARY KEY AUTOINCREMENT, " + "NAME TEXT, " + "IMAGE_RESOURCE_ID BLOB);");

    upgradeDatabase(db);
}

public void upgradeDatabase (SQLiteDatabase db) {
    convertToBitmap();
    byteArray = convertToByte();
    addItems(db);
}

public void convertToBitmap () {
    Bitmap faan = BitmapFactory.decodeResource(context.getResources(), R.drawable.faan);
    Bitmap milk = BitmapFactory.decodeResource (context.getResources(), R.drawable.milk);
    Bitmap egg = BitmapFactory.decodeResource (context.getResources(), R.drawable.egg);
    Bitmap toilet_tissue = BitmapFactory.decodeResource (context.getResources(), R.drawable.toilet_tissue);
    Bitmap kitchen_tissue = BitmapFactory.decodeResource (context.getResources(), R.drawable.kitchen_tissue);
    Bitmap bread = BitmapFactory.decodeResource (context.getResources(), R.drawable.bread);
    Bitmap potatoe = BitmapFactory.decodeResource (context.getResources(), R.drawable.potatoe);
    Bitmap onion = BitmapFactory.decodeResource (context.getResources(), R.drawable.onion);
    Bitmap flour = BitmapFactory.decodeResource (context.getResources(), R.drawable.flour);
    Bitmap tomatoe = BitmapFactory.decodeResource (context.getResources(), R.drawable.tomatoe);
    Bitmap corriandor = BitmapFactory.decodeResource (context.getResources(), R.drawable.corriandor);

    bitmapArray = new ArrayList <Bitmap> ();

    bitmapArray.add(faan);
    bitmapArray.add (milk);
    bitmapArray.add (egg);
    bitmapArray.add (toilet_tissue);
    bitmapArray.add (kitchen_tissue);
    bitmapArray.add (bread);
    bitmapArray.add (potatoe);
    bitmapArray.add (onion);
    bitmapArray.add (flour);
    bitmapArray.add (tomatoe);
    bitmapArray.add (corriandor);

}

public byte [] convertToByte () {

    ByteArrayOutputStream stream = new ByteArrayOutputStream ();

    for (Bitmap bitmap : bitmapArray) {
        bitmap.compress (Bitmap.CompressFormat.PNG, 0, stream);
    }

    return stream.toByteArray();
}

public static Bitmap getImages (byte [] image) {
    return BitmapFactory.decodeByteArray(image, 0, image.length);
}

public void addItems (SQLiteDatabase db) {

    byte faan = byteArray [0];
    byte milk = byteArray [1];
    byte egg = byteArray [2];
    byte toilet_tissue = byteArray [3];
    byte kitchen_tissue = byteArray [4];
    byte bread = byteArray [5];
    byte potatoe = byteArray [6];
    byte onion = byteArray [7];
    byte flour = byteArray [8];
    byte tomatoe = byteArray [9];
    byte corriandor = byteArray [10];

    insertItems (db, "Faan", faan);
    insertItems (db, "Milk", milk);
    insertItems (db, "Egg", egg);
    insertItems (db, "Toilet Tissue", toilet_tissue);
    insertItems (db, "Kitchen Tissue", kitchen_tissue);
    insertItems (db, "Bread", bread);
    insertItems (db, "Potatoe", potatoe);
    insertItems (db, "Onion", onion);
    insertItems (db, "Flour", flour);
    insertItems (db, "Tomatoe", tomatoe);
    insertItems (db, "Corriandor", corriandor);

}

public void insertItems (SQLiteDatabase db, String name, byte image) {
    ContentValues contentValues = new ContentValues();
    contentValues.put ("NAME", name);
    contentValues.put ("IMAGE_RESOURCE_ID", image);

    db.insert ("GROCERY_ITEMS", null, contentValues);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("CREATE TABLE GROCERY_ITEMS (" + "_id INTEGER PRIMARY KEY AUTOINCREMENT, " + "NAME TEXT, " + "IMAGE_RESOURCE_ID BLOB);");

    upgradeDatabase(db);
}
}

回收者视图类

package com.myapps.myapplication;

import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

public class grocery_item extends AppCompatActivity {

SQLiteDatabase db;
Cursor cursor;

protected void onCreate (Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.item_grocery);

    accessDataBase();

    RecyclerView groceryRecycler = (RecyclerView) findViewById(R.id.grocery_recycler_view);

    captionedImagesAdapter adapter = new captionedImagesAdapter (this, cursor);
    GridLayoutManager layoutManager = new GridLayoutManager(this, 2, GridLayoutManager.VERTICAL, false);
    groceryRecycler.setLayoutManager(layoutManager);
    groceryRecycler.setAdapter (adapter);
}

public void accessDataBase () {
    MyDatabaseHelper databaseHelper = new MyDatabaseHelper(this);

    try {

        db = databaseHelper.getReadableDatabase();

        cursor = db.query ("GROCERY_ITEMS", new String[] {"NAME", "IMAGE_RESOURCE_ID"}, null, null, null, null, null);

    } catch (SQLiteException e) {
        e.printStackTrace();
    }
}
}

回收站视图适配器：

package com.myapps.myapplication;

import android.content.Context;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.recyclerview.widget.RecyclerView;
import androidx.cardview.widget.CardView;

public class captionedImagesAdapter extends RecyclerView.Adapter <captionedImagesAdapter.ViewHolder> {

private Context context;
private Cursor cursor;

public captionedImagesAdapter (Context context, Cursor cursor) {
    this.context = context;
    this.cursor = cursor;
}

public captionedImagesAdapter.ViewHolder onCreateViewHolder (ViewGroup parent, int viewType) {
    LayoutInflater inflater = LayoutInflater.from(context);
    CardView cv = (CardView) inflater.inflate(R.layout.card_view, parent, false);

    return new ViewHolder (cv);
}

public void onBindViewHolder(ViewHolder holder, int position) {
    if (!cursor.moveToPosition(position)) {
        return;
    }

    String info_text = cursor.getString (0);
    byte [] info_image = cursor.getBlob(1);

    Bitmap bitmap = MyDatabaseHelper.getImages(info_image);

    holder.textView.setText(info_text);
    holder.imageView.setImageBitmap(bitmap);
}

public int getItemCount() {
    return cursor.getCount();
}

public static class ViewHolder extends RecyclerView.ViewHolder {
    private ImageView imageView;
    private TextView textView;

    public ViewHolder(CardView view) {
        super(view);
        imageView = view.findViewById(R.id.info_image);
        textView = view.findViewById(R.id.info_text);
    }
}
}

例外：

android.database.sqlite.SQLiteException: unknown error (code 0 SQLITE_OK): INTEGER data in nativeGetBlob 
    at android.database.CursorWindow.nativeGetBlob(Native Method)
    at android.database.CursorWindow.getBlob(CursorWindow.java:434)
    at android.database.AbstractWindowedCursor.getBlob(AbstractWindowedCursor.java:47)
    at com.myapps.myapplication.captionedImagesAdapter.onBindViewHolder(captionedImagesAdapter.java:43)
    at com.myapps.myapplication.captionedImagesAdapter.onBindViewHolder(captionedImagesAdapter.java:14)
    at androidx.recyclerview.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:7178)
    at androidx.recyclerview.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:7258)
    at androidx.recyclerview.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:6125)
    at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6391)
    at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6231)
    at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6227)
    at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2330)
    at androidx.recyclerview.widget.GridLayoutManager.layoutChunk(GridLayoutManager.java:572)
    at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1591)
    at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:668)
    at androidx.recyclerview.widget.GridLayoutManager.onLayoutChildren(GridLayoutManager.java:170)
    at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4230)
    at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:3941)
    at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:4499)
    at android.view.View.layout(View.java:22085)
    at android.view.ViewGroup.layout(ViewGroup.java:6290)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
    at android.view.View.layout(View.java:22085)
    at android.view.ViewGroup.layout(ViewGroup.java:6290)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
    at android.view.View.layout(View.java:22085)
    at android.view.ViewGroup.layout(ViewGroup.java:6290)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
    at android.view.View.layout(View.java:22085)
    at android.view.ViewGroup.layout(ViewGroup.java:6290)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
    at android.view.View.layout(View.java:22085)
    at android.view.ViewGroup.layout(ViewGroup.java:6290)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
    at com.android.internal.policy.DecorView.onLayout(DecorView.java:786)
    at android.view.View.layout(View.java:22085)
    at android.view.ViewGroup.layout(ViewGroup.java:6290)
    at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:3333)
    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2810)
    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1930)
    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7988)
    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1154)
    at android.view.Choreographer.doCallbacks(Choreographer.java:977)
    at android.view.Choreographer.doFrame(Choreographer.java:893)
    at android.view.Choreographer$FrameHandler.handleMessage(Choreographer.java:1082)
    2020-08-12 13:34:17.755 14399-14399/com.myapps.myapplication E/AndroidRuntime:     at 
    android.os.Handler.dispatchMessage(Handler.java:107)
    at android.os.Looper.loop(Looper.java:214)
    at android.app.ActivityThread.main(ActivityThread.java:7682)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:516)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)
4

2 回答 2

1

从哪里开始？

  1. 您命名的列表明您在IMAGE_RESOURCE_ID其中存储了某种标识号，但它的类型BLOB表明内容实际上是图像数据本身。这种混淆本身不是问题，但表明代码编写时并没有明确的方向。
  2. 您将所有图像存储到单个流中，而无法挑选出单独的图像。如果您想将实际数据存储在数据库中，则应将每个位图编码为单独的byte[].
  3. 您获取结果 mega- 的前 11 个字节byte[]并仅将它们存储在数据库中（也存储在 11 个不同的行中）。这些字节可能只是第一个图像的标头的开头，它们本身没有任何用处。

我的建议： 如果要存储实际数据，请更改convertToBytes方法以获取Bitmap参数并为要存储在数据库中的每个 Bitmap 调用一次。

于 2020-08-12T12:56:40.053 回答
0

听起来您查询中的第二列不是您认为的 blob；您正在使用 .getBlob(1) 访问它，这意味着：取第二列的值并将其作为 blob 提供给我，错误似乎表明：.. 不可以，它不是 blob，它是一个整数。

您尚未粘贴创建AbstractWindowedCursor 对象的位置；它是传递给captionedImagesAdapter类的构造函数的游标。这背后有什么疑问？我敢打赌，它SELECT foo, bar, baz FROM something实际上bar不是一个 blob 值。例如，如果您这样做了SELECT * FROM GROCERY_ITEMS，那么第一列（.getInt(0)例如）是 id 列，第二列是名称（文本），第三列是 blob。如果您尝试在其上运行，您最终会收到与此类似的错误.getBlob(1)，因为1是错误的数字。

于 2020-08-12T12:59:05.327 回答