问请求索引0，大小为0
EN

Stack Overflow用户

提问于 2018-06-06 02:41:28

回答 1查看 150关注 0票数 0

当我尝试从android.database.CursorIndexOutOfBoundsException:数据库中列出数据时，我得到了一个Sqlite索引0请求，大小为0的错误。通过读取具有相同错误的其他问题，我可以断定第一条记录有一个空值。解决方案似乎是关闭光标，但我已经这样做了，所以这不是原因。除非我错误地关闭了光标。我已经发布了我得到的错误和我认为与该错误相关的代码。任何有关如何解决此错误的指导都将不胜感激。

Process: ca.rvogl.tpbcui, PID: 30793
    android.database.CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0
        at android.database.AbstractCursor.checkPosition(AbstractCursor.java:460)
        at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:136)
        at android.database.AbstractWindowedCursor.getInt(AbstractWindowedCursor.java:68)
        at ca.rvogl.tpbcui.Database.DatabaseHelper.getGame(DatabaseHelper.java:445)
        at ca.rvogl.tpbcui.Views.GameActivity.createGame(GameActivity.java:113)
        at ca.rvogl.tpbcui.Views.GameActivity.access$800(GameActivity.java:30)
        at ca.rvogl.tpbcui.Views.GameActivity$7.onClick(GameActivity.java:244)
        at android.view.View.performClick(View.java:5637)
        at android.view.View$PerformClick.run(View.java:22429)
        at android.os.Handler.handleCallback(Handler.java:751)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6119)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

来自我的DatabaseHelper的代码

public Game  getGame(String leagueId, String bowlerId, String seriesId) {
        //Get Readable Database If We Are Not Inserting Anything
        SQLiteDatabase db = this.getReadableDatabase();

        Cursor cursor = db.query( Game.TABLE_NAME,
                new String[]{Game.COLUMN_ID, Game.COLUMN_LEAGUE_ID, Game.COLUMN_BOWLER_ID,
                        Game.COLUMN_SERIES_ID, Game.COLUMN_SCORE, Game.COLUMN_STRIKES, Game.COLUMN_SPARES,Game.COLUMN_SPLITS, Game.COLUMN_SPLIT_CONVERSIONS, Game.COLUMN_OPEN_FRAMES, Game.COLUMN_TIMESTAMP},
                Game.COLUMN_LEAGUE_ID + "=?" + " AND " +  Game.COLUMN_BOWLER_ID + "=?" + " AND " +  Game.COLUMN_SERIES_ID + "=?",
                new String[]{String.valueOf(leagueId), String.valueOf(bowlerId), String.valueOf(seriesId)}, null, null, null, null);

        if (cursor != null)
            cursor.moveToFirst();

        //Prepare Game Object
        Game game = new Game(

                cursor.getInt(cursor.getColumnIndex(Game.COLUMN_ID)),
                cursor.getString(cursor.getColumnIndex(Game.COLUMN_LEAGUE_ID)),
                cursor.getString(cursor.getColumnIndex(Game.COLUMN_BOWLER_ID)),
                cursor.getString(cursor.getColumnIndex(Game.COLUMN_SERIES_ID)),
                cursor.getString(cursor.getColumnIndex(Game.COLUMN_SCORE)),
                cursor.getString(cursor.getColumnIndex(Game.COLUMN_STRIKES)),
                cursor.getString(cursor.getColumnIndex(Game.COLUMN_SPARES)),
                cursor.getString(cursor.getColumnIndex(Game.COLUMN_SPLITS)),
                cursor.getString(cursor.getColumnIndex(Game.COLUMN_SPLIT_CONVERSIONS)),
                cursor.getString(cursor.getColumnIndex(Game.COLUMN_OPEN_FRAMES)),
                cursor.getString(cursor.getColumnIndex(Game.COLUMN_TIMESTAMP)));

        //Close Database Connection
        cursor.close();

        return game;
    }

    public List<Game> getAllGames(String leagueId, String bowlerId, String seriesId) {
        List<Game> games = new ArrayList<>();

        //Select All Query
        String selectQuery = "SELECT  * FROM " + Game.TABLE_NAME + " WHERE " + Game.COLUMN_LEAGUE_ID + " = '" + leagueId + "'" + " AND " + Game.COLUMN_BOWLER_ID + " = '" + bowlerId + "'" + " AND " + Game.COLUMN_SERIES_ID + " = '" + seriesId + "'" + " ORDER BY " +
                Game.COLUMN_TIMESTAMP + " DESC";

        try (SQLiteDatabase db = this.getWritableDatabase()) {
            @SuppressLint("Recycle") Cursor cursor = db.rawQuery( selectQuery, null );

            //Looping Through All Rows And Adding To The List
            if (cursor.moveToFirst()) {
                do {
                    Game game1 = new Game();
                    game1.setId(cursor.getInt(cursor.getColumnIndex(Game.COLUMN_ID ) ) );
                    game1.setLeagueId(cursor.getString(cursor.getColumnIndex(Game.COLUMN_LEAGUE_ID)));
                    game1.setBowlerId(cursor.getString(cursor.getColumnIndex(Game.COLUMN_BOWLER_ID)));
                    game1.setSeriesId(cursor.getString(cursor.getColumnIndex(Game.COLUMN_SERIES_ID)));
                    game1.setScore(cursor.getString(cursor.getColumnIndex(Game.COLUMN_SCORE)));
                    game1.setSpares(cursor.getString(cursor.getColumnIndex(Game.COLUMN_SPARES)));
                    game1.setSplits(cursor.getString(cursor.getColumnIndex(Game.COLUMN_SPLITS)));
                    game1.setSplitConversions(cursor.getString(cursor.getColumnIndex(Game.COLUMN_SPLIT_CONVERSIONS)));
                    game1.setOpenFrames(cursor.getString(cursor.getColumnIndex(Game.COLUMN_OPEN_FRAMES)));
                    game1.setTimestamp(cursor.getString(cursor.getColumnIndex(Game.COLUMN_TIMESTAMP)));

                    games.add( game1 );
                } while (cursor.moveToNext());
            }

            //Close Database Connection
            db.close();
        }

        //Return Game List
        return games;
    }

来自Games.java的代码

//Inserting New Game In The Database & Refreshing The List
    private void createGame(String leagueId, String bowlerId, String seriesId, String score, String spares, String strikes, String splits, String splitConversions, String openFrames) {
        //Inserting Game In The Database & Getting Newly Inserted Game Id
        long id = db.insertGame(leagueId, bowlerId, seriesId, score, strikes, spares, splits, splitConversions, openFrames);

        //Getting The Newly Inserted Game From The Database
        Game n = db.getGame(leagueId, bowlerId, seriesId);

        if (n != null) {
            //Adding New Game To The Array at Position 0
            gameList.add(0, n);

            //Refreshing The List
            mAdapter.notifyDataSetChanged();

            toggleEmptyGames();
        }
    }

    //Updating Game In The Database & Updating Item In The List By Its Position
    private void updateGame(String score, String strikes, String spares, String splits, String splitConversions, String openFrames, int position) {
        Game n = gameList.get(position);
        //Updating the Game Text
        n.setScore(score);
        n.setStrikes(strikes);
        n.setSpares(spares);
        n.setSplits(splits);
        n.setSplitConversions(splitConversions);
        n.setOpenFrames(openFrames);

        //Updating Game In The Database
        db.updateGame(n);

        //Refreshing The List
        gameList.set(position, n);
        mAdapter.notifyItemChanged(position);

        toggleEmptyGames();
    }

    //Deleting Game From SQWLite & Removing The Item From The List By Its Position
    private void deleteGame(int position) {
        //Deleting Game From The Database
        db.deleteGame(gameList.get(position));

        //Removing Game From The List
        gameList.remove(position);
        mAdapter.notifyItemRemoved(position);

        toggleEmptyGames();
    }

    //Opens Dialog With Edit - Delete Options
    private void showActionsDialog(final int position) {
        CharSequence colors[] = new CharSequence[]{"Edit", "Delete"};

        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Choose option");
        builder.setItems(colors, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                if (which == 0) {
                    showGameDialog(true, gameList.get(position), position);
                } else {
                    deleteGame(position);
                }
            }
        });
        builder.show();
    }

此错误仅在我尝试将另一个游戏添加到数据库时出现。当我重新启动应用程序时，输入的数据出现在列表视图中，但是有些字段缺少值，这是不正确的。

修订后的代码

public Game  getGame(String leagueId, String bowlerId, String seriesId) {
        //Get Readable Database If We Are Not Inserting Anything
        SQLiteDatabase db = this.getReadableDatabase();

        Cursor cursor = db.query( Game.TABLE_NAME,
                new String[]{Game.COLUMN_ID, Game.COLUMN_LEAGUE_ID, Game.COLUMN_BOWLER_ID,
                        Game.COLUMN_SERIES_ID, Game.COLUMN_SCORE, Game.COLUMN_STRIKES, Game.COLUMN_SPARES, Game.COLUMN_SPLITS, Game.COLUMN_SPLIT_CONVERSIONS, Game.COLUMN_OPEN_FRAMES, Game.COLUMN_TIMESTAMP},
                Game.COLUMN_LEAGUE_ID + "=?" + " AND " + Game.COLUMN_BOWLER_ID + "=?" + " AND " + Game.COLUMN_SERIES_ID + "=?",
                new String[]{String.valueOf( leagueId ), String.valueOf( bowlerId ), String.valueOf( seriesId )}, null, null, null, null );


        // if (cursor.getCount()>0)
        //    cursor.moveToFirst();
        // Log.d("Events",Integer.toString(cursor.getCount()));
        if (cursor.moveToFirst()) {
            //Prepare Game Object
            Game game = new Game(

                    cursor.getInt( cursor.getColumnIndex( Game.COLUMN_ID ) ),
                    cursor.getString( cursor.getColumnIndex( Game.COLUMN_LEAGUE_ID ) ),
                    cursor.getString( cursor.getColumnIndex( Game.COLUMN_BOWLER_ID ) ),
                    cursor.getString( cursor.getColumnIndex( Game.COLUMN_SERIES_ID ) ),
                    cursor.getString( cursor.getColumnIndex( Game.COLUMN_SCORE ) ),
                    cursor.getString( cursor.getColumnIndex( Game.COLUMN_STRIKES ) ),
                    cursor.getString( cursor.getColumnIndex( Game.COLUMN_SPARES ) ),
                    cursor.getString( cursor.getColumnIndex( Game.COLUMN_SPLITS ) ),
                    cursor.getString( cursor.getColumnIndex( Game.COLUMN_SPLIT_CONVERSIONS ) ),
                    cursor.getString( cursor.getColumnIndex( Game.COLUMN_OPEN_FRAMES ) ),
                    cursor.getString( cursor.getColumnIndex( Game.COLUMN_TIMESTAMP ) ) );

            //Close Database Connection
            cursor.close();

            return game;
        } else {
        }
    }

javascript

android

sqlite

android-cursor

cursor-position

回答 1

Stack Overflow用户

回答已采纳

发布于 2018-06-06 04:04:42

出现此错误的原因有两个。首先，查询没有返回任何行，当从方法返回的游标不是null时，您正在检查query null游标是否为null，因此查询没有正确检查/处理这些行。它可能是空的 (cursor.getCount()将返回0)。

所有的Cursor move????方法都返回true或false，这取决于是否可以进行移动。

因此，为了正确地处理读取游标，你应该永远不要使用(这是没有用的，而且在你的例子中是破坏性的) :-

if (cursor != null) {
    cursor.moveToFirst(); // (or any move???? method
    ..... Ouch if the Cursor is empty as there will be no first row to extract data from
}

相反，您应该使用：

if (cursor.moveToFirst()) {
    ..... do your stuff here
} else {
    ..... handle no row found here if wanted
}

对于游标的循环，您可以使用:-

while (cursor.moveToNext()) {
    .... handle each row here
}

如果您需要遍历游标，并且不处理游标中的任何行，则可以使用:-

if (cursor.getCount() < 1) {
    ..... handle no rows here
}
while (cursor.moveToNext()) {
    ..... handle each row here
}

请注意，在任何情况下，您都应该在使用光标时将其关闭。

票数 1

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/50706917

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