Android - 某些页面不存在 SQLite 列

Question

我正在为 Android 应用程序处理一些 SQLite 数据库。我有一个包含多个玩家的“玩家”表，以及一个包含每个玩家技能点的一对多“技能”表，例如投篮和篮板。

我在应用程序中有一项活动，用于实际填写文本框并将播放器插入数据库。当用户点击“添加玩家”按钮时，会在“玩家”表中插入一行，在“技能”表中插入一行，该表具有引用“玩家”表的外键。在这些插入之后，我进行了查询以检查是否可以从“技能”表中读取“射击”值并将其放入 Toast 通知中。效果很好，我使用的代码在这里：

SQLiteDatabase db2 = dbHelper.getReadableDatabase();

String[] projection = { "shooting" };

String sortOrder = "shooting" + " DESC";

Cursor c = db2.query(
    "skills",       // The table to query
    projection,     // The columns to return
    null,           // The columns for the WHERE clause
    null,           // The values for the WHERE clause
    null,           // don't group the rows
    null,           // don't filter by row groups
    sortOrder       // The sort order
);

c.moveToFirst();

int shooting = c.getInt(c.getColumnIndexOrThrow("shooting"));

Toast.makeText(this, "" + shooting, Toast.LENGTH_SHORT).show();

在我看到这行得通后，我将其注释掉并添加了一个 Intent，以便在插入玩家和技能后让应用切换到“名册”活动。在“名册”活动中，我想获得每个球员的“射门”技能。当我使用上面完全相同的代码（适用于其他活动）时，我收到一条错误消息：

06-16 15:59:42.602：E/AndroidRuntime(31537)：java.lang.RuntimeException：无法启动活动 ComponentInfo{com.silverray.messaround/com.silverray.messaround.Roster}：java.lang。 IllegalArgumentException：“射击”列不存在

当我知道我将它包含在我的 SQL Create 语句中时，我无法弄清楚为什么它说“射击”列不存在，而且我什至能够用另一个相同的代码读取这个完全相同的列活动。

感谢阅读。有什么想法吗？

编辑：这是名册活动的完整代码：

public class Roster extends Activity {

    int teamID = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_roster);

        // CHECK ROSTER

        DatabaseContract dbContract = new DatabaseContract();
        DatabaseContract.DbHelper dbHelper = dbContract.new DbHelper(this);

        SQLiteDatabase dbCheck = dbHelper.getReadableDatabase();

        Intent intent = getIntent();
        int ID = intent.getIntExtra("ID", 1);
        teamID = ID;

        String stringID = String.valueOf(ID);

        String[] projection = { "_id, playerFirstName, playerLastName, playerPosition" };
        String sortOrder = "playerFirstName" + " ASC";

        Cursor c = dbCheck.query(
            "player",
            projection,
            null,
            null,
            null,
            null,
            sortOrder
        );

        c.moveToFirst();

        int rowsAffected = c.getCount();

        if (rowsAffected < 1) {
            TextView rosterList = (TextView) findViewById(R.id.txtListRoster);
            rosterList.setText("Your team doesn't have any players!");
            c.close();
            dbCheck.close();
        } else {
            String players = "";

            for (int l = 0; l < rowsAffected; l++) {            
                String playerName = c.getString(c.getColumnIndexOrThrow("playerFirstName"));
                String playerLastName = c.getString(c.getColumnIndexOrThrow("playerLastName"));     
                String position = c.getString(c.getColumnIndexOrThrow("playerPosition"));
                int playerID = c.getInt(c.getColumnIndexOrThrow("_id"));        
                String player_ID = String.valueOf(playerID);
                String pos = "";

                if (position.equals("Point Guard")) {
                    pos = "PG";
                } else if (position.equals("Shooting Guard")) {
                    pos = "SG";
                } else if (position.equals("Small Forward")) {
                    pos = "SF";
                } else if (position.equals("Power Forward")) {
                    pos = "PF";
                } else if (position.equals("Center")) {
                    pos = "C";
                }

                SQLiteDatabase db2 = dbHelper.getReadableDatabase();

                String[] projection2 = { "shooting" };

                String sortOrder2 = "shooting" + " DESC";

                Cursor c2 = db2.query(
                    "skills",
                    projection2,
                    null,
                    null,
                    null,
                    null,
                    sortOrder2
                );

                c2.moveToFirst();

                //** Everything works until this line:

                int shooting = c2.getInt(c.getColumnIndexOrThrow("shooting"));

                players += playerName + " " + playerLastName + " (" + pos + ") Shooting: ";

                if (l != (rowsAffected - 1)) {
                    players += "\n";
                }

                TextView rosterList = (TextView) findViewById(R.id.txtListRoster);
                rosterList.setText(players);

                if (l != (rowsAffected - 1)) {
                    c.moveToNext();
                }

                c2.close();
            }

            c.close();
            dbCheck.close();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.roster, menu);
        return true;
    }

    public void addPlayer(View view) {

        Intent goToAddPlayer = new Intent(this, AddPlayer.class);
        goToAddPlayer.putExtra("ID", teamID);
        this.startActivity(goToAddPlayer);
        this.finish();
        return;
    }
}

Answer 1

int shooting = c2.getInt(c.getColumnIndexOrThrow("shooting"));

应该是

int shooting = c2.getInt(c2.getColumnIndexOrThrow("shooting"));

您现在正在处理第二个查询，但尝试从第一个查询获取列索引。