我有一个加载的 tableviewcells 列表。在每个单元格旁边都有一个“添加到收藏夹”按钮。单击“添加到收藏夹”时，其上的图像将发生变化，并且更改后的图像应存储到 coredata 中，以便再次运行该应用程序时我可以知道哪个单元格被收藏了。为此，这就是已经尝试过的...
func favoriteBtnTapped(cell: HistoryTableViewCell) {
if segmentControl.selectedSegmentIndex == 2 {
favBtnTapFlag = true
if let indexPath = tableview?.indexPath(for: cell) {
let myFavMsg = messages1[indexPath.row]
let likedMsg = myFavMsg.historyData
guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else {
return
}
let managedContext = appDelegate.persistentContainer.viewContext
let entity = NSEntityDescription.entity(forEntityName: "FavoritedMessages", in: managedContext)
let category = NSManagedObject(entity: entity!, insertInto: managedContext)
category.setValue(likedMsg, forKeyPath: "favData")
//New image is set on the cell and it is saved to coredata here...
cell.favoriteButton.setImage(UIImage(named: "pin"), for: .normal)
let imageData = UIImageJPEGRepresentation((cell.favoriteButton.imageView?.image)!, 1)
category.setValue(imageData, forKey: "favImage")
do {
try managedContext.save()
self.favMessages.append(category as! FavoritedMessages)
} catch let error as NSError {
print("Could not save. \(error), \(error.userInfo)")
}
}
}
它是在 viewWillAppear 中获取的，就像这样...
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
guard let appDelegate =
UIApplication.shared.delegate as? AppDelegate else {
return
}
let managedContext =
appDelegate.persistentContainer.viewContext
let fetchRequest =
NSFetchRequest<NSManagedObject>(entityName: "Messages")
let fetchRequest1 = NSFetchRequest<NSManagedObject>(entityName: "FavoritedMessages")
do {
messages1 = try managedContext.fetch(fetchRequest as! NSFetchRequest<NSFetchRequestResult>) as! [Messages]
favMessages = try managedContext.fetch(fetchRequest1 as! NSFetchRequest<NSFetchRequestResult>) as! [FavoritedMessages]
for result in favMessages as [FavoritedMessages] {
if let imageData = result.value(forKey: "favImage") as? NSData {
if let image = UIImage(data:imageData as Data) as? UIImage {
favoritedImage.image = image
}
}
}
tableview.reloadData()
} catch let error as NSError {
print("Could not fetch. \(error), \(error.userInfo)")
}}
此处 favoritedImage.image = image 我试图将获取的图像分配给 imageview 变量，然后在 cellForRow 处分配它。但我不确定如何做到这一点......
最佳答案
您不应该将图像保存在 coredata 中。
将 favourite_status 为 1 的模型保存在 coredata 中(0 => unfavoured and 1 => favorite )。 (基本上是 bool 值) 根据 favourite_status 从 app bundle 加载图像。
加载单元格时也使用 favourite_status 加载图像。
///已编辑
func favoriteBtnTapped(cell: HistoryTableViewCell) {
//1. Get Entity from datasource(Array) using indexpath.row
//2. Favorite the entity by setting favaorite_status = 1
//3. Save to coredata also
//4. Reload Table view
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
//1. Get Entity from datasource(Array) using indexpath= Array
//2. Set cell image based on favaorite_status. Use UIImage.init(name:””) (if favaorite_status == 0, imagename will be different)
}
关于ios - 将图像设置为核心数据，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/47751493/