Question

我的bean类中有两个日期变量

public class bean {
    private Date dos;
    private Date doe;
}

在我的DAO课程中

// columns in my sqlite database table
public class TaskDAO extends SQLiteOpenHelper {

    public static final String  C_DOS = "d1";
    public static final String  C_DOE = "d2";

    @Override
    public void onCreate(SQLiteDatabase db) {

        StringBuilder sb = new StringBuilder();
        sb.append("CREATE TABLE "+TBNAME);
        sb.append(" ("+ID+" INTEGER PRIMARY KEY AUTOINCREMENT, ");
        sb.append(C_DOS+" INTEGER,");
        sb.append(C_DOE+" INTEGER)");

        String sql = sb.toString();
        db.execSQL(sql);
    }

    void addbean(bean b)
    {
        SQLiteDatabase database = this.getWritableDatabase();
        ContentValues values = new ContentValues();

        values.put(C_DOS,b.getdos);
        values.put(C_DOE,b.getdoe);

        database.insert(TBNAME,null,values);
    }

ContentValues put给出了不兼容类型的错误。我如何解决这个问题，以便我可以提取后者在其他DAO CRUD函数中使用它？

Answer 1

使用Long作为类型。

因此，您可以将mDate.getTime()存储在您的数据库中，并使用new Date(millies)

获取正确的时间

public boolean addBean(Bean bean) {

    long result;
    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();
    values.put(ID, bean.getId());
    values.put(C_DOS, formatDateToLong(bean.getDos()));
    values.put(C_DOE, formatDateToLong(bean.getDoe()));

    result = db.insert(TBNAME, null, values);
    db.close();

    return result > 0;
}

因此您可以使用辅助函数。

public static Date formatLongToDate(Long date){
     return new Date(date);
}

public static Long formatDateToLong(Date date){
    return date.getTime();
}

如果您使用数据库，最好在模型中使用id：

public class Bean {
    private Long id;
    private Date dos;
    private Date doe;
}

要从数据库中获取数据，请尝试：

 public Bean getBean(Long id) {

    SQLiteDatabase db = getReadableDatabase();
    Cursor cursor = db.query(TBNAME, new String[] { ID, C_DOS, C_DOE}, ID + " = " + id, null, null, null, null);

    Bean mBean = null;
    if (cursor.moveToFirst()){
        new mBean (
            cursor.getLong(0),
            DateHelper.formatLongToDate(cursor.getLong(1)),
            DateHelper.formatLongToDate(cursor.getLong(2))
        );
    }

    cursor.close();
    db.close();
    return mBean ;
}

Answer 2

你可以用这个

    public class SQLiteHandler extends SQLiteOpenHelper {

    private static final String TAG = SQLiteHandler.class.getSimpleName();

    // All Static variables
    // Database Version
    private static final int DATABASE_VERSION = 1;

    // Database Name
    private static final String DATABASE_NAME = "user_data";

    // Login table name
    private static final String TABLE_USER = "user";

    // Login Table Columns names
    private static final String KEY_ID = "id";
    private static final String KEY_NAME = "name";
    private static final String KEY_EMAIL = "email";
    private static final String KEY_UID = "uid";
    private static final String KEY_CREATED_AT = "created_at";

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

    // Creating Tables
    @Override
    public void onCreate(SQLiteDatabase db) {
        String CREATE_LOGIN_TABLE = "CREATE TABLE " + TABLE_USER + "("
                + KEY_ID + " INTEGER PRIMARY KEY," + KEY_UID + " TEXT,"
                + KEY_EMAIL + " TEXT UNIQUE," + KEY_NAME + " TEXT,"
                + KEY_CREATED_AT + " TEXT" + ")";
        db.execSQL(CREATE_LOGIN_TABLE);

        Log.d(TAG, "Database tables created");
    }

    // Upgrading database
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // Drop older table if existed
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_USER);

        // Create tables again
        onCreate(db);
    }

    /**
     * Storing user details in database
     * */
    public void addUser(String uid, String email, String name, String created_at) {
        SQLiteDatabase db = this.getWritableDatabase();

        ContentValues values = new ContentValues();
        values.put(KEY_UID, uid); // Name
        values.put(KEY_EMAIL, email); // Email
        values.put(KEY_NAME, name); // Email
        values.put(KEY_CREATED_AT, created_at); // Created At

        // Inserting Row
        long id = db.insert(TABLE_USER, null, values);
        db.close(); // Closing database connection

        Log.d(TAG, "New user inserted into sqlite: " + id);
    }

    /**
     * Getting user data from database
     * */
    public HashMap<String, String> getUserDetails() {
        HashMap<String, String> user = new HashMap<String, String>();
        String selectQuery = "SELECT  * FROM " + TABLE_USER;

        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);
        // Move to first row
        cursor.moveToFirst();
        if (cursor.getCount() > 0) {
            user.put("uid", cursor.getString(1));
            user.put("email", cursor.getString(2));
            user.put("name", cursor.getString(3));
            user.put("created_at", cursor.getString(4));
        }
        cursor.close();
        db.close();
        // return user
        Log.d(TAG, "Fetching user from Sqlite: " + user.toString());

        return user;
    }

    /**
     * Re crate database Delete all tables and create them again
     * */
    public void deleteUsers() {
        SQLiteDatabase db = this.getWritableDatabase();
        // Delete All Rows
        db.delete(TABLE_USER, null, null);
        db.close();

        Log.d(TAG, "Deleted all user info from sqlite");
    }
}

之后你可以插入这样的数据......

SQLiteHandler db = new SQLiteHandler(this);
db.addUser(_uni_id,_email,_username,_reg_date);

你也可以获得这样的数据......

SQLiteHandler db = new SQLiteHandler(getApplicationContext());

    // Fetching user details from sqlite
    HashMap<String, String> user = db.getUserDetails();
    String name = user.get("username_key");

for drop all（您可以编辑SQLiteHandler类来删除特定行）...

db.deleteUsers();

我希望它对你有用

Answer 3

我不明白以下代码：

values.put(C_DOS,b.getdos);
values.put(C_DOE,b.getdoe);

是吗

values.put(C_DOS,b.getdos());
values.put(C_DOE,b.getdoe());

你正试图做什么？

如果要将时间存储为整数，请将以上两行修改为：

values.put(C_DOS,b.getdos().getTime());
values.put(C_DOE,b.getdoe().getTime());

我假设您getdos班级中定义了getdoe和bean，并且返回类型为Date。

是否可以编辑您的问题以包含您正在显示的错误消息？在编译时不会检查使用ContentValues添加到put的值的类型，因此，不兼容的类型错误可能是由其他内容引起的，而不是由于Date类型引起的。

如何在sqlite数据库android studio中添加日期

3 个答案: