我的 Android Studio 更新到了 2.3.1 版本，当时我正在使用我的
project.Ad当我尝试在模拟器中查看该应用程序时。我从 Nexus 7 API 24 开始，当我想登录时，我迷上了，并收到此错误：
引起：android.database.sqlite.SQLiteException：没有这样的列：user_id（代码1）：，编译时：SELECT task_Id，user_id，title，content FROM Todos WHERE user_id =？
这一行：
在 com.ToDo.todoTasks.sql.DatabaseHelper.getTaskByUser(DatabaseHelper.java:149)
指的是：
Cursor cursor = db.query
里面是哪一个
public ArrayList < ToDo > getTaskByUser()
public ArrayList < ToDo > getTaskByUser() {
// array of columns to fetch
String[] columns = {
TASK_ID,
user_id,
TITLE,
CONTENT
};
ArrayList < ToDo > taskList = new ArrayList < ToDo > ();
SQLiteDatabase db = this.getReadableDatabase();
// query the user table
SharedPreferences pref = ctx.getSharedPreferences("LOGIN", Context.MODE_PRIVATE);
String userid = pref.getString("USER_NUM", null);
Cursor cursor = db.query(
mTODO,
columns,
"user_id = ?",
new String[] {
userid
},
null,
null,
null);
// Traversing through all rows and adding to list
if (cursor.moveToFirst()) {
do {
ToDo todo = new ToDo();
todo.setId(Integer.parseInt(cursor.getString(cursor.getColumnIndex(TASK_ID))));
todo.setTitle(cursor.getString(cursor.getColumnIndex(TITLE)));
todo.setUserID(cursor.getString(cursor.getColumnIndex(user_id)));
todo.setContent(cursor.getString(cursor.getColumnIndex(CONTENT)));
// Adding user record to list
taskList.add(todo);
} while (cursor.moveToNext());
}
cursor.close();
db.close();
// return user list
return taskList;
}
DatabaseHelperpublic class DatabaseHelper extends SQLiteOpenHelper {
Context ctx;
// Database Version
private static final int DB_VER = 1;
// Database Name
private static final String DATABASE_NAME = "UserManager.db";
// User table name
private static final String TABLE_USER = "user";
// User Table Columns names
private static final String COLUMN_USER_ID = "user_id";
private static final String COLUMN_USER_NAME = "user_name";
private static final String COLUMN_USER_EMAIL = "user_email";
private static final String COLUMN_USER_PASSWORD = "user_password";
//Table mToDo task name
private final static String mTODO = "Todos";
//Todos table columns names
private final static String TASK_ID = "task_Id"; //autoincrement
private final static String user_id = "user_id";
private final static String TITLE = "title";
private final static String CONTENT = "content";
// create table sql query
private String CREATE_USER_TABLE = "CREATE TABLE " + TABLE_USER + "(" +
COLUMN_USER_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," + COLUMN_USER_NAME + " TEXT," +
COLUMN_USER_EMAIL + " TEXT," + COLUMN_USER_PASSWORD + " TEXT" + ")";
private String CREATE_mTODO_TABLE = "CREATE TABLE " + mTODO + "(" +
TASK_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," + user_id + "TEXT" +
TITLE + " TEXT," + CONTENT + " TEXT" + ")";
// drop table sql query
private String DROP_USER_TABLE = "DROP TABLE IF EXISTS " + TABLE_USER;
/**
* Constructor
*
* @param context
*/
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DB_VER);
this.ctx = context;
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_USER_TABLE);
db.execSQL(CREATE_mTODO_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
//Drop User Table if exist
db.execSQL(DROP_USER_TABLE);
// Create tables again
onCreate(db);
}
/**
* This method is to create user record
*
* @param user
*/
public void add(User user) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(COLUMN_USER_NAME, user.getName());
values.put(COLUMN_USER_EMAIL, user.getEmail());
values.put(COLUMN_USER_PASSWORD, user.getPassword());
// Inserting Row
db.insert(TABLE_USER, null, values);
db.close();
}
public void add(ToDo todoTask) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(TITLE, todoTask.getTitle());
values.put(CONTENT, todoTask.getContent());
values.put(user_id, todoTask.getUserID());
// Inserting Row
db.insert(mTODO, null, values);
db.close();
}
public void update(ToDo todo) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(TITLE, todo.getTitle());
values.put(CONTENT, todo.getContent());
// Inserting Row
db.update(mTODO, values, "task_Id=" + todo.getId(), null);
db.close();
}
public ToDo getTaskById(int taskid) {
SQLiteDatabase d = this.getReadableDatabase();
ToDo todo = new ToDo();
String[] columns = {
TASK_ID,
TITLE,
CONTENT,
user_id
};
Cursor cursor = d.query(
mTODO,
columns,
"task_Id = ?", //Where value
new String[] {
String.valueOf(taskid)
},
null,
null,
null
);
try {
if (cursor.moveToFirst()) {
todo.setId(Integer.parseInt(cursor.getString(cursor.getColumnIndex(TASK_ID))));
todo.setTitle(cursor.getString(cursor.getColumnIndex(TITLE)));
todo.setUserID(cursor.getString(cursor.getColumnIndex(user_id)));
todo.setContent(cursor.getString(cursor.getColumnIndex(CONTENT)));
// Adding user record to list
}
} catch (Exception e) {
e.printStackTrace();
}
return todo;
}
public boolean checkUser(String email) {
// array of columns to fetch
String[] columns = {
COLUMN_USER_ID
};
SQLiteDatabase db = this.getReadableDatabase();
// selection criteria
String selection = COLUMN_USER_EMAIL + " = ?";
// selection argument
String[] selectionArgs = {
email
};
// query user table with condition
Cursor cursor = db.query(
TABLE_USER, //Table to query
columns, //columns to return
selection, //columns for the WHERE clause
selectionArgs, //The values for the WHERE clause
null, //group the rows
null, //filter by row groups
null); //The sort order
int cursorCount = cursor.getCount();
cursor.close();
db.close();
if (cursorCount > 0) {
return true;
}
return false;
}
/**
* This method to check user exist or not
*/
public long checkUser(String email, String password) {
// array of columns to fetch
String[] columns = {
COLUMN_USER_ID
};
SQLiteDatabase db = this.getReadableDatabase();
// selection criteria
String selection = COLUMN_USER_EMAIL + " = ? " + " AND " + COLUMN_USER_PASSWORD + " = ?";
// selection arguments
String[] selectionArgs = {
email,
password
};
// query user table with conditions
long userid = 0;
Cursor cursor = db.query(TABLE_USER, //Table to query
columns, //columns to return
selection, //columns for the WHERE clause
selectionArgs, //The values for the WHERE clause
null, //group the rows
null, //filter by row groups
null); //The sort order
cursor.moveToFirst();
int cursorCount = cursor.getCount();
if (cursorCount > 0) {
userid = cursor.getLong(0);
cursor.close();
db.close();
return userid;
}
return 0;
}
public void deleteRow(ToDo todo) {
SQLiteDatabase db = this.getWritableDatabase();
// delete user record by id
db.delete(mTODO, TASK_ID + " = ?", new String[] {
String.valueOf(todo.getId())
});
db.close();
}
}
我哪里做错了？
private String CREATE_mTODO_TABLE = "CREATE TABLE " + mTODO + "("
+ TASK_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," + user_id + "TEXT"
注意列名称和类型之间的空格：
^
添加缺失的空间后，您可以卸载应用程序以重新创建数据库。