Question

我有一个不起作用的变异器，我在这里看了一下，尝试了一些建议，但似乎没有任何东西能让它发挥作用。

这是我的模特：

...

protected $fillable = [
    'energy_types'
];

...

public function getEnergyTypesAttribute($value)
{
    $types = explode(',', $value);
    $fuels = array();
    foreach($types as $type){
        switch ($type){
            case '2':
                $fuelType = 'Gas (Reticulated)';
                break;
            case '3':
                $fuelType = 'Gas (Bottled)';
                break;
            default:
                $fuelType = 'Electricity';
        }
        $fuels[] = array(   "id" => $type,
                            "name" => $fuelType);
    }

    return $fuels;
}

以如下方式存储在数据库中：

energy_types

1

1,2

1

控制器：

if($participant->isRetailer){
       $retail = Retailer::find($participant->id);
       $participant->energyTypes = $retail->energy_types;

如果我在这里进行 $ retail 的转储， energy_types 仍然如此：

["energy_types"]=>
    string(3) "1,2"

我尝试过更改 $ retail 的方式，重新迁移，尝试设置属性（也不起作用）。

我做错了什么？

Answer 1

首先，Mutator函数类似于“ setEnergyTypesAttribute”。

但是，您的代码段显示您正在尝试定义访问器。

无论如何，如果您试图在从数据库中检索数据时向模型添加自定义属性，请按照以下步骤操作。

class ViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {

    @IBOutlet weak var colView: UICollectionView!

    var imageCache = NSCache<NSString, UIImage>()
    var arrURLs = [
        "https://homepages.cae.wisc.edu/~ece533/images/airplane.png",
        "https://homepages.cae.wisc.edu/~ece533/images/arctichare.png",
        "https://homepages.cae.wisc.edu/~ece533/images/baboon.png",
        "https://homepages.cae.wisc.edu/~ece533/images/barbara.png",
        "https://homepages.cae.wisc.edu/~ece533/images/boat.png",
        "https://homepages.cae.wisc.edu/~ece533/images/cat.png",
        "https://homepages.cae.wisc.edu/~ece533/images/fruits.png",
        "https://homepages.cae.wisc.edu/~ece533/images/frymire.png",
        "https://homepages.cae.wisc.edu/~ece533/images/girl.png",
        "https://homepages.cae.wisc.edu/~ece533/images/goldhill.png",
        "https://homepages.cae.wisc.edu/~ece533/images/lena.png",
        "https://homepages.cae.wisc.edu/~ece533/images/monarch.png",
        "https://homepages.cae.wisc.edu/~ece533/images/mountain.png",
        "https://homepages.cae.wisc.edu/~ece533/images/peppers.png",
        "https://homepages.cae.wisc.edu/~ece533/images/pool.png",
        "https://homepages.cae.wisc.edu/~ece533/images/sails.png",
        "https://homepages.cae.wisc.edu/~ece533/images/serrano.png",
        "https://homepages.cae.wisc.edu/~ece533/images/tulips.png",
        "https://homepages.cae.wisc.edu/~ece533/images/watch.png",
        "https://homepages.cae.wisc.edu/~ece533/images/zelda.png"
    ]


func downloadImage(url: URL, imageView: UIImageView, placeholder : UIImage) {

    imageView.image = placeholder // Set default placeholder..

    // Image is set if cache is available
    if let cachedImage = imageCache.object(forKey: url.absoluteString as NSString) {
        imageView.image = cachedImage
    } else {
        // Reset the image to placeholder as the URLSession fetches the new image
        imageView.image = placeholder
        URLSession.shared.dataTask(with: url) { (data, response, error) in
            guard error == nil else  {
                // You should be giving an option to retry the image here
                imageView.image = placeholder
                return
            }

            if let respo  = response as? HTTPURLResponse {

                print("Status Code : ", respo.statusCode)

                if let imageData = data, let image = UIImage(data: imageData) {
                    self.imageCache.setObject(image, forKey: url.absoluteString as NSString)
                    // Update the imageview with new data
                    DispatchQueue.main.async {
                        imageView.image = image
                    }
                } else {
                    // You should be giving an option to retry the image here
                    imageView.image = placeholder
                }
            }
            }.resume()
    }
}


    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        let w = self.view.bounds.width - 30

        return CGSize(width: w, height: w + 60)
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return arrURLs.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "DummyCollectionViewCell", for: indexPath) as! DummyCollectionViewCell

        let str = arrURLs[indexPath.item]
        let url = URL(string: str)

        downloadImage(url: url!) { (img) in
            DispatchQueue.main.async {
                cell.imgView.image = img ?? UIImage(named: "placeholder")
            }
        }

        return cell
    }
}

其中“ bar”是模型中的原始属性。

希望有帮助。

Laravel 5.4 Mutator无法正常工作

1 个答案: