【发布时间】：2017-04-28 12:47:39
【问题描述】：
我的图像不会加载到图像视图中，直到您将单元格从表格中滚动并重新打开，或者转到另一个视图并返回视图（重绘单元格）。
如何让它们正确加载？
/////////
我的 viewDidLoad 里面有这个：
tableView.delegate = self
tableView.dataSource = self
DispatchQueue.global(qos: .background).async {
self.getBusinesses()
DispatchQueue.main.async {
self.tableView.reloadData()
}
}
我在viewDidLoad中调用的.getBusinesses函数中调用了下载图片的函数：
func getBusinesses() -> Array<Business> {
var businessList = Array<Business>()
//let id = 1
let url = URL(string: "**example**")!
let data = try? Data(contentsOf: url as URL)
var isnil = false
if data == nil{
isnil = true
}
print("is nill is \(isnil)")
if(data == nil){
print("network error")
businessList = []
return businessList
}
else{
values = try! JSONSerialization.jsonObject(with: data!, options: JSONSerialization.ReadingOptions.mutableContainers) as! NSDictionary
}
let json = JSON(values)
var i = 0;
for (key, values) in json {
var businessReceived = json[key]
let newBusiness = Business(id: "18", forename: "", surname: "", email: "", password: "", business: true, level: 1, messageGroups: [], problems: [])
newBusiness.name = businessReceived["name"].stringValue
newBusiness.description = businessReceived["description"].stringValue
newBusiness.rating = Int(businessReceived["rating"].doubleValue)
newBusiness.category = businessReceived["category"].intValue
newBusiness.distance = Double(arc4random_uniform(198) + 1)
newBusiness.image_url = businessReceived["image"].stringValue
newBusiness.url = businessReceived["url"].stringValue
newBusiness.phone = businessReceived["phone"].stringValue
newBusiness.postcode = businessReceived["postcode"].stringValue
newBusiness.email = businessReceived["email"].stringValue
newBusiness.id = businessReceived["user_id"].stringValue
if(newBusiness.image_url == ""){
newBusiness.getImage()
}
else{
newBusiness.image = #imageLiteral(resourceName: "NoImage")
}
if(businessReceived["report"].intValue != 1){
businessList.append(newBusiness)
}
}
businesses = businessList
print(businesses.count)
holdBusinesses = businessList
return businessList
}
在业务对象中，我有这种方法可以从 url 下载图像并将其存储在业务对象的图像属性中：
func getImage(){
if(self.image_url != ""){
print("runs imageeee")
var storage = FIRStorage.storage()
// This is equivalent to creating the full reference
let storagePath = "http://firebasestorage.googleapis.com\(self.image_url)"
var storageRef = storage.reference(forURL: storagePath)
// Download in memory with a maximum allowed size of 1MB (1 * 1024 * 1024 bytes)
storageRef.data(withMaxSize: 30 * 1024 * 1024) { data, error in
if let error = error {
// Uh-oh, an error occurred!
} else {
// Data for "images/island.jpg" is returned
self.image = UIImage(data: data!)!
print("returned image")
}
}
}
else{
self.image = #imageLiteral(resourceName: "NoImage")
}
}
然后我在这里的tableview中输出：
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = self.tableView.dequeueReusableCell(withIdentifier: "Cell", for : indexPath) as! BusinessesViewCell
cell.businessImage.image = businesses[(indexPath as NSIndexPath).row].image
//.............
return cell
}
【问题讨论】：
-
用SDwebImage就好了
-
但如果您记得下载是异步的，则更相关 - 因此当您在 viewDidLoad 中调用 tableView.reloadData() 时没有可用数据 - 查看委托调用，并使用它们来触发视图仅在数据可用时重新加载 tableView
-
听起来很有趣，如果它在下载图像时加载了 tableview 那就完美了！你有这方面的经验吗@Russell
-
您在哪里使用返回的图像填充数组业务[]？ downloadImage() 似乎只是设置了一个值。另外 - 如果你在同一个类中做所有事情，它甚至比使用委托更简单 - 只需确保从下载的完成处理程序中刷新 tableView
-
在 viewdidload 中调用的 getBusinesses 函数中，现在将修改原始代码供您查看@Russell
标签： ios swift firebase tableview tableviewcell