Question

我昨天和今天一直在争取这个，我得到了一个简单的SQLite插件，它一直返回-1作为返回值，我读到某处将主键名更改为_id但没有做任何更改。

所以这里是代码的快照。我的领域常数：

//BALLS TABLE
public  static final String BALLS_TABLE  = "balls";
public  static final String BALL_ID = "id";
public  static final String BALL_USERID = "userId";
public  static final String BALL_MODEL = "model";
public  static final String BALL_BRAND = "brand";
public  static final String BALL_SERIAL = "serial";
public  static final String BALL_NOTES = "notes";
public  static final String BALL_IMAGE = "image";

然后在我的createTables（SQLiteDatabase db）上我得到了

// BALLS TABLE

db.execSQL(
"create table " + BALLS_TABLE +" (" +
BALL_ID + " integer primary key autoincrement not null," +
BALL_USERID + "integer not null," +
BALL_MODEL + " text not null," +
BALL_BRAND + " text not null," +
BALL_SERIAL + " text not null," +
BALL_NOTES + " text not null," +
BALL_IMAGE + " blob" +
");");

表的创建正在进行，因为我已经填充了其他表。

最后是整个球助手类

package com.kegel.android.bowlermanager.data;

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

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

public class BallHelper {

    private SQLiteDatabase database;
    private ArrayList<Ball> currentBalls;
    private Context context;

    public BallHelper(Context context,SQLiteDatabase database)
    {
        this.context = context;
        this.database = database;
        loadBalls();
    }

    public ArrayList<Ball> getCurrentBalls() {
        return currentBalls;
    }

    public Boolean BallExists(long id)
    {
        for (Ball ball : currentBalls)
        {
            if (ball.getId() == id)
                return true;
        }   
        return false;
    }

    public Boolean BallExists(Ball u)
    {
        for (Ball ball : currentBalls)
        {
            if (ball.getId() == u.getId())
                return true;
        }   
        return false;
    }

    public void updateBall(Ball b) {
        assert(null != b);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        byte[] by = null;
        if (b.getImage() != null )
        {
            Bitmap bmp = b.getImage();
            bmp.compress(Bitmap.CompressFormat.PNG, 100, baos);   
            by = baos.toByteArray();  

        }
        ContentValues values = new ContentValues();
        values.put(SQLiteOpenDataHelper.BALL_USERID, 1);
        values.put(SQLiteOpenDataHelper.BALL_MODEL, b.getModel());
        values.put(SQLiteOpenDataHelper.BALL_BRAND , b.getBrand());
        values.put(SQLiteOpenDataHelper.BALL_SERIAL , b.getSerial());
        values.put(SQLiteOpenDataHelper.BALL_NOTES, b.getNotes());
        values.put(SQLiteOpenDataHelper.BALL_IMAGE , by);
        if (b.isValid())
        {
            if (b.getId() == 0)
            {
                b.setId(database.insert(SQLiteOpenDataHelper.BALLS_TABLE, null, values));
            }
            else
            {
                long id = b.getId();
                String where = String.format("%s = %d", SQLiteOpenDataHelper.BALL_ID, id);
                database.update(SQLiteOpenDataHelper.BALLS_TABLE, values, where, null);
            }
            loadBalls();    
        }
    }
    public void deleteBalls(Long id) {
        String where = String.format("%s in (%s)", SQLiteOpenDataHelper.BALL_ID, id);
        database.delete(SQLiteOpenDataHelper.BALLS_TABLE, where, null);
        loadBalls();
    }
    public void deleteBalls(Ball u) {
        String where = String.format("%s in (%s)", SQLiteOpenDataHelper.BALL_ID, u.getId());
        database.delete(SQLiteOpenDataHelper.BALLS_TABLE, where, null);
        loadBalls();
    }
        private void loadBalls() {
        byte[] img = null;
        currentBalls = new ArrayList<Ball>();
        //try
        //{
        Cursor ballsCursor = database.query(SQLiteOpenDataHelper.BALLS_TABLE, new String[] {SQLiteOpenDataHelper.BALL_ID,SQLiteOpenDataHelper.USER_ID, SQLiteOpenDataHelper.BALL_MODEL, SQLiteOpenDataHelper.BALL_BRAND, SQLiteOpenDataHelper.BALL_SERIAL, SQLiteOpenDataHelper.BALL_NOTES, SQLiteOpenDataHelper.BALL_IMAGE}, null, null, null, null, null);
        ballsCursor.moveToFirst();
        Ball b;
        if (! ballsCursor.isAfterLast()) {
            do {
                long id = ballsCursor.getInt(0);
                long bowlerId  = ballsCursor.getLong(1);
                String model = ballsCursor.getString(2);
                String brand = ballsCursor.getString(3);
                String serial = ballsCursor.getString(4);
                String notes = ballsCursor.getString(5);
                img = ballsCursor.getBlob(6);
                Bitmap bmp=BitmapFactory.decodeByteArray(img,0,img.length);
                b = new Ball(context,bowlerId,model,brand,serial,notes);
                b.setId(id);
                b.setImage(bmp);
                currentBalls.add(b);
            } while (ballsCursor.moveToNext());
        }
        ballsCursor.close();
    }
}

这里的第二双眼睛会派上用场！所以，如果有人能在这里发现任何东西，或者让我知道如果我遗失了什么，我将非常感激。我已经检查了b上的值（甚至通过了我的内部验证）但是这样的插入将失败：

Bitmap bm = BitmapFactory.decodeResource(getResources(), R.drawable.fake_pofile);
Ball ball = new Ball(this,1, "Test", "Test", "", "");
ball.setImage(bm);
mHelper.updateBall(ball);

Answer 1

嗯......因为我没有，没有人注意到表创建的代码，在字段BALL_USERID之间我没有留下空间所以它是一个完整的单词，有趣的事情，db.exec应该是抛出异常，但在这种情况下没有并接受一个奇怪的名称作为没有类型的字段，并创建没有字段“userId”但没有类型的“useridinteger”的表（如果你没有设置，是否有默认类型一个??）

有时只是那些可以让你疯狂的小事。

Answer 2

我知道这是一个古老的示例，但是对于正在寻找Objective C示例的任何人来说，这都是很好的。但是，请确保在return语句之前放置sqlite3_reset（statement）行。否则，该代码仅在第一次保存或查找时有效。

SQLite插入失败

2 个答案: