android - 无法从 CursorWindow 读取行

Question

我正在开发一个 Android 应用程序，我想在其中实现一个添加新用户的注册功能。

首先，我创建了一个名为 Registration 的 Activity ，当按下按钮时，它会调用一个添加用户的方法:

public User createUser(String username, String password, String email) {
            ContentValues values = new ContentValues();
            values.put(MySQLiteHelperUsers.COLUMN_USERNAME, username);
            values.put(MySQLiteHelperUsers.COLUMN_PASSWORD, password);
            values.put(MySQLiteHelperUsers.COLUMN_EMAIL, email);
            long insertId = database.insert(MySQLiteHelperUsers.TABLE_USERS, null,
                values);
            Cursor cursor = database.query(MySQLiteHelperUsers.TABLE_USERS,
                allColumns, MySQLiteHelperUsers.COLUMN_ID + " = " + insertId, null,
                null, null, null);
            cursor.moveToFirst();
            User newUser = cursorToUser(cursor);
            cursor.close();
            return newUser;
}

这是 cursorToUser 方法:

private User cursorToUser(Cursor cursor) {
        User user = new User();
        user.setId(cursor.getLong(cursor.getColumnIndex("_id")));
        user.setUsername(cursor.getString(cursor.getColumnIndex("_username")));
        user.setPassword(cursor.getString(cursor.getColumnIndex("_password")));
        user.setEmail(cursor.getString(cursor.getColumnIndex("_email")));
        return user;
}

但它给了我这个错误:

    05-10 13:09:35.081: E/AndroidRuntime(16380): FATAL EXCEPTION: main
05-10 13:09:35.081: E/AndroidRuntime(16380): java.lang.IllegalStateException: Could not execute method of the activity
05-10 13:09:35.081: E/AndroidRuntime(16380):    at android.view.View$1.onClick(View.java:3704)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at android.view.View.performClick(View.java:4232)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at android.view.View$PerformClick.run(View.java:17298)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at android.os.Handler.handleCallback(Handler.java:615)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at android.os.Handler.dispatchMessage(Handler.java:92)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at android.os.Looper.loop(Looper.java:137)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at android.app.ActivityThread.main(ActivityThread.java:4921)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at java.lang.reflect.Method.invokeNative(Native Method)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at java.lang.reflect.Method.invoke(Method.java:511)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at dalvik.system.NativeStart.main(Native Method)
05-10 13:09:35.081: E/AndroidRuntime(16380): Caused by: java.lang.reflect.InvocationTargetException
05-10 13:09:35.081: E/AndroidRuntime(16380):    at java.lang.reflect.Method.invokeNative(Native Method)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at java.lang.reflect.Method.invoke(Method.java:511)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at android.view.View$1.onClick(View.java:3699)
05-10 13:09:35.081: E/AndroidRuntime(16380):    ... 11 more
05-10 13:09:35.081: E/AndroidRuntime(16380): Caused by: java.lang.IllegalStateException: Couldn't read row 0, col -1 from CursorWindow.  Make sure the Cursor is initialized correctly before accessing data from it.
05-10 13:09:35.081: E/AndroidRuntime(16380):    at android.database.CursorWindow.nativeGetLong(Native Method)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at android.database.CursorWindow.getLong(CursorWindow.java:511)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at android.database.AbstractWindowedCursor.getLong(AbstractWindowedCursor.java:75)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at dao.UsersDataSource.cursorToUser(UsersDataSource.java:75)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at dao.UsersDataSource.createUser(UsersDataSource.java:44)
05-10 13:09:35.081: E/AndroidRuntime(16380):    at com.example.pocket_city.Registration.registrationClick(Registration.java:47)
05-10 13:09:35.081: E/AndroidRuntime(16380):    ... 14 more
05-10 13:09:35.141: D/dalvikvm(16380): GC_CONCURRENT freed 177K, 14% free 9641K/11143K, paused 15ms+4ms, total 79ms

这是 MySQLiteHelperUsers 类:

public class MySQLiteHelperUsers extends SQLiteOpenHelper{
    public static final String TABLE_USERS = "users";
    public static final String COLUMN_ID = "_id";
    public static final String COLUMN_USERNAME = "_username";
    public static final String COLUMN_PASSWORD = "_password";
    public static final String COLUMN_EMAIL = "_email";

    private static final String DATABASE_NAME = "users.db";
    private static final int DATABASE_VERSION = 1;

    // Database creation sql statement
    private static final String DATABASE_CREATE = "CREATE TABLE "
            + TABLE_USERS.trim() + "(" 
            + COLUMN_ID.trim() + " INTEGER PRIMARY KEY AUTOINCREMENT, " 
            + COLUMN_USERNAME.trim() + " TEXT NOT NULL, "
            + COLUMN_PASSWORD.trim() + " TEXT NOT NULL, "
            + COLUMN_EMAIL.trim()  
            + " TEXT NOT NULL)";

    public MySQLiteHelperUsers(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase database) {
        database.execSQL(DATABASE_CREATE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_USERS);
        onCreate(db);
    }

注册 Activity :

    public class Registration extends Activity {
        UsersDataSource usersDataSource = null;
        User user = null;

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


            usersDataSource = new UsersDataSource(getApplicationContext());
            usersDataSource.open();
        }


        public void registrationClick(View view){
            EditText editUsername = (EditText) findViewById(R.id.editUsername);
                String username = editUsername.getText().toString();
            EditText editPassw = (EditText) findViewById(R.id.editPassw);
                String passw = editPassw.getText().toString();
            EditText editPassw2 = (EditText) findViewById(R.id.editPassw2);
                String passw2 = editPassw2.getText().toString();
            EditText editEmail = (EditText) findViewById(R.id.editEmail);
                String email = editEmail.getText().toString();
            EditText editEmail2 = (EditText) findViewById(R.id.editEmail2);
                String email2 = editEmail2.getText().toString();
            System.out.println("PASSW= "+passw+" "+passw2);
            System.out.println("EMAIL= "+email+" "+email2);

            /*if(!passw.equals(passw2) && !email.equals(email2)){
                Toast.makeText(getApplicationContext(), "Le password/email non sono uguali!", Toast.LENGTH_LONG).show();
            }*/

            usersDataSource.createUser(username, passw, email);
            /*Toast.makeText(getApplicationContext(), "Registrazione riuscita!", Toast.LENGTH_LONG).show();*/       


        }    
}

Answer 1

您尝试获取的一列或多列似乎在光标中丢失了。

检查创建 allColumns 时是否包含所有列:

String[] allColumns = {"_id", "_username", "_password", "_email"};