Question

我正在尝试将TIMESTAMP列添加到我的SQLite数据库中。该列用于使用＆＃34; System.currentTimeMillis（）;＆＃34;来捕获时间戳数据。应用程序崩溃，错误来自下面显示的** **行中的游标代码。错误读取＆＃34;无法启动活动ComponentInfo {... ListActivity}：java.lang.IllegalStateException：无法从CursorWindow读取第0行，第6列。在从中访问数据之前，请确保Cursor已正确初始化。＆＃34;

最初我在模型文件中将变量设置为String。然后我尝试了很长时间，但都没有工作。我在这里缺少什么？

UserData文件：

...
public long getTimestamp() {
    return timestamp;
}

public void setTimestamp(long timestamp) {
    this.timestamp = timestamp;

DatabaseHelper.java文件：

...
private static final String SQL_CREATE_ENTRIES =
        "CREATE TABLE IF NOT EXISTS " + DBContract.DBEntry.TABLE_NAME +
            "(" + DBContract.DBEntry.COLUMN_NAME_ID +
                  " INTEGER PRIMARY KEY AUTOINCREMENT,"
                + DBContract.DBEntry.COLUMN_NAME_TODO +
                  " TEXT,"
                + DBContract.DBEntry.COLUMN_NAME_NOTE1 +
                  " TEXT,"
                + DBContract.DBEntry.COLUMN_NAME_NOTE2 +
                  " TEXT,"
                + DBContract.DBEntry.COLUMN_NAME_DUEDATE +
                  " TEXT,"
                + DBContract.DBEntry.COLUMN_NAME_DUETIME +
                " TEXT,"
                + DBContract.DBEntry.COLUMN_NAME_TIMESTAMP +
                  " TEXT" + ")";
...

public void insertIntoDB(String todo, String note1, String note2, String duedate, String duetime, long timestamp) {

    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();
    values.put(DBContract.DBEntry.COLUMN_NAME_TODO, todo);
    values.put(DBContract.DBEntry.COLUMN_NAME_NOTE1, note1);
    values.put(DBContract.DBEntry.COLUMN_NAME_NOTE2, note2);
    values.put(DBContract.DBEntry.COLUMN_NAME_DUEDATE, duedate);
    values.put(DBContract.DBEntry.COLUMN_NAME_DUETIME, duetime);        
    values.put(DBContract.DBEntry.COLUMN_NAME_TIMESTAMP, timestamp);

    db.insert(DBContract.DBEntry.TABLE_NAME, null, values);
    db.close();
}
...

Cursor cursor = db.rawQuery(query,null);

        try {
            if (cursor.moveToFirst()) {
                do {
                    UserData userData = new UserData();
                    userData.setTodo(cursor.getString(1));
                    userData.setNote1(cursor.getString(2));
                    userData.setNote2(cursor.getString(3));
                    userData.setDuedate(cursor.getString(4));
                    userData.setDuetime(cursor.getString(5));
                    **userData.setTimestamp(cursor.getLong(6));**

                    modelList.add(0, userData);
                    } while (cursor.moveToNext());
...

ListAdapter.java文件：

...
public void onBindViewHolder(final ListViewHolder holder, final int position) {
    ...
    holder.cardBlankText5.setText((int) dbList.get(position).getTimestamp());

Activity.java文件：

...
public void onClickSave(View v) {
    ...
    long timestamp=System.currentTimeMillis();
    helper = new DatabaseHelper(Activity.this);
    helper.insertIntoDB(todo,note1,note2,duedate,duetime,timestamp);
    startActivity(new Intent(Activity.this,ListActivity.class));
}

Answer 1

将DBContract.DBEntry.COLUMN_NAME_TIMESTAMP作为DATETIME类型应该有效。我通常有实用程序方法，它接受游标和列名称并返回Date对象：

public static Date getDateColumn(Cursor c, String column) {
    Date d = null;
    Long time = c.getLong(c.getColumnIndexOrThrow(column));
    if (time != null && time != 0) {
         d = new Date();
         d.setTime(time);
    }
    return d;
}

要检查的第二件事是您的查询中是否要求该字段。共享query的值可能会有所帮助，但是当您要求的列不在预测中时，通常会得到类似的内容。

e.g。从mytable中选择columnA，columnB;然后你试着从columnC得到一些不在结果中的东西。

Answer 2

不要尝试从声明为TEXT的列中获取Long。将其声明为INTEGER。或者使用getString（）并将值转换为Long。

Android：如何修复SQLite数据库的时间戳添加？

2 个答案: