小编s_s*_*s_s的帖子

我正在尝试以UICollectionView编程方式创建.我需要在单元格内添加标签,所以我创建了CollectionViewCell类.

这是班级:

import UIKit

class MyCollectionViewCell: UICollectionViewCell {

    override init(frame: CGRect) {
        super.init(frame: frame)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

这是collectionView实现类:

import UIKit

class TwoViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout, UICollectionViewDelegate {

    let leftAndRightPaddings: CGFloat = 80.0
    let numberOfItemsPerRow: CGFloat = 7.0
    let screenSize: CGRect = UIScreen.main.bounds
    private let cellReuseIdentifier = "collectionCell"
    var items = ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", …

我将 Django 应用程序上传到 Heroku，然后使用 Heroku 文档中的以下 3 个命令配置 cleardb 附加组件：

heroku addons:create cleardb:ignite
heroku config | grep CLEARDB_DATABASE_URL
heroku config:set DATABASE_URL='mysql://adffdadf2341:adf4234@us-cdbr-east.cleardb.com/heroku_db?reconnect=true'

它似乎没问题并且应用程序正在运行（但没有数据库）。现在我尝试运行：

$ heroku run python manage.py migrate

这是我得到的错误：

Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "/app/.heroku/python/lib/python3.5/site-packages/django/core/management/__init__.py", line 363, in execute_from_command_line
    utility.execute()
  File "/app/.heroku/python/lib/python3.5/site-packages/django/core/management/__init__.py", line 355, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/app/.heroku/python/lib/python3.5/site-packages/django/core/management/base.py", line 283, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/app/.heroku/python/lib/python3.5/site-packages/django/core/management/base.py", line 327, in execute
    self.check()
  File "/app/.heroku/python/lib/python3.5/site-packages/django/core/management/base.py", line 359, in check
    include_deployment_checks=include_deployment_checks,
  File "/app/.heroku/python/lib/python3.5/site-packages/django/core/management/commands/migrate.py", line …