如何在iOS中使用URL和NSString在UIImageView上显示图片？

Question

如何在iOS中使用URL和NSString在UIImageView上显示图片？

7

我想在 UIImageView 上使用 URL 和 NSString 显示图片，但是我无法显示出来。

我的代码如下：

UIImageView *view_Image = [[UIImageView alloc]initWithFrame:CGRectMake(view_Image_Pos_X, view_Image_Pos_Y, 179, 245)];

view_Image.backgroundColor = [UIColor greenColor];
view_Image.tag = img;
view_Image.userInteractionEnabled=YES;
view_Image.autoresizesSubviews = YES;
view_Image.alpha = 0.93;  
[self.view addSubview:view_Image];

我正在尝试的是：

 if (img == 0) {


 NSString *url_Img1 = @"http://opensum.in/app_test_f1/;";
 NSString *url_Img2 = @"45djx96.jpg";

 NSString *url_Img_FULL = [NSString stringWithFormat:@"%@%@", url_Img1,url_Img2];

 NSLog(@"Show url_Img_FULL: %@",url_Img_FULL);



 NSURL *url_img = [NSURL URLWithString:url_Img_FULL];
 NSLog(@"Show: url_img %@",url_img);

// Here below line working perfectly and image is showing             

view_Image.image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:@"http://opensum.in/app_test_f1/45djx96.jpg"]]];   // working code

但我不想这样做，我想连接两个URL生成一个URL(即url_Img_FULL)，然后像下面一样传递给图片：

UIImage *image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:url_Img_FULL]]]; // 不起作用

我希望从“url_Img_FULL”(即两个URL的组合)中显示图像。您还可以检查URL是否正常工作。有什么建议吗？

- Areeba Khan

1

NSString *url_Img1 = @"http://opensum.in/app_test_f1/;"; 你的URL以";"结尾。 - Giorgio Marziani de Paolis

1

你在url_Img1的值末尾加了一个分号，我猜这就是问题所在。 - tkanzakic

10个回答

12

只管去做

NSString *imgURL = @"imagUrl";

NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:imgURL]];

[YourImgView setImage:[UIImage imageWithData:data]];

使用 GCD：如果你不想让你的应用程序挂起，那么可以在后台下载图片。

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        NSString *imgURL = @"imagUrl";
        NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:imgURL]];

    //set your image on main thread.
    dispatch_async(dispatch_get_main_queue(), ^{
        [YourImgView setImage:[UIImage imageWithData:data]];
    });    
});

- Rajneesh071

2

针对Swift 3.0

class ImageLoader {


var cache = NSCache<AnyObject, AnyObject>()

class var sharedLoader : ImageLoader {
    struct Static {
        static let instance : ImageLoader = ImageLoader()
    }
    return Static.instance
}

func imageForUrl(urlString: String, completionHandler:@escaping (_ image: UIImage?, _ url: String) -> ()) {

    DispatchQueue.global().async {
        let data: NSData? = self.cache.object(forKey: urlString as AnyObject) as? NSData

        if let goodData = data {
            let image = UIImage(data: goodData as Data)
            DispatchQueue.main.async {
                completionHandler(image, urlString)
            }
            return
        }

        let url:NSURL = NSURL(string: urlString)!
        let task = URLSession.shared.dataTask(with: url as URL) {
            data, response, error in
            if (error != nil) {
                print(error?.localizedDescription)
                completionHandler(nil, urlString)
                return
            }

            if data != nil {
                let image = UIImage(data: data!)
                self.cache.setObject(data as AnyObject, forKey: urlString as AnyObject)
                DispatchQueue.main.async {
                    completionHandler(image, urlString)
                }
                return
            }
        }
        task.resume()
    }

}
}

用法

ImageLoader.sharedLoader.imageForUrl(urlString: imageUrl as! String) { (image, url) in
            self.imageView.image = image
}

- Manish Khandelwal

1

从以下代码中获取图像

NSData *imageUrl = [NSData dataWithContentsOfURL:[NSURL URLWithString:@"Your image URL Here"]];

然后使用以下代码设置图像

[UIImage imageWithData:imageUrl];

- Mohd Kalimullah Sheikh

1

试一下这个

NSString* combinedString = [stringUrl1 stringByAppendingString stringUrl2];

- Ali Majeed

1

   dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    NSString *str = self.recordlarge[@"images"];
    NSLog(@"Project Gallery id Record : %@",str);
    NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:str]];
    dispatch_async(dispatch_get_main_queue(), ^{
        [self.myimagelarge setImage:[UIImage imageWithData:data]];
    });    
});

- Dilip Tiwari

0

针对Swift 3.0

同步执行：

if let filePath = Bundle.main().pathForResource("imageName", ofType: "jpg"), image = UIImage(contentsOfFile: filePath) {
    imageView.contentMode = .scaleAspectFit
    imageView.image = image
}

异步方式：

创建一个带有完成处理程序的方法，从您的URL获取图像数据

func getDataFromUrl(url:URL, completion: ((data: Data?, response: URLResponse?, error: NSError? ) -> Void)) {
    URLSession.shared().dataTask(with: url) {
        (data, response, error) in
        completion(data: data, response: response, error: error)
    }.resume()
}

创建一个方法来下载图片（启动任务）。

func downloadImage(url: URL){
    print("Download Started")
    getDataFromUrl(url: url) { (data, response, error)  in
        DispatchQueue.main.sync() { () -> Void in
            guard let data = data where error == nil else { return }
            print(response?.suggestedFilename ?? url.lastPathComponent ?? "")
            print("Download Finished")
            self.imageView.image = UIImage(data: data)
        }
    }
}

使用方法：

override func viewDidLoad() {
    super.viewDidLoad()
    print("Begin of code")
    if let checkedUrl = URL(string: "http://www.apple.com/euro/ios/ios8/a/generic/images/og.png") {
        imageView.contentMode = .scaleAspectFit
        downloadImage(url: checkedUrl)
    }
    print("End of code. The image will continue downloading in the background and it will be loaded when finished.")
}

扩展：

extension UIImageView {
    func downloadedFrom(link: String, contentMode mode: UIViewContentMode = .scaleAspectFit) {
        guard let url = URL(string: link) else { return }
        contentMode = mode
        URLSession.shared().dataTask(with: url) { (data, response, error) in
            guard
                let httpURLResponse = response as? HTTPURLResponse where httpURLResponse.statusCode == 200,
                let mimeType = response?.mimeType where mimeType.hasPrefix("image"),
                let data = data where error == nil,
                let image = UIImage(data: data)
                else { return }
            DispatchQueue.main.sync() { () -> Void in
                self.image = image
            }
        }.resume()
    }
}

使用方法：

override func viewDidLoad() {
    super.viewDidLoad()
    print("Begin of code")
    imageView.downloadedFrom(link: "http://www.apple.com/euro/ios/ios8/a/generic/images/og.png")
    print("End of code. The image will continue downloading in the background and it will be loaded when finished.")

}

- Moin Shirazi

0

我测试了您的URL并找到了问题。

问题出在这行代码：

NSString *url_Img1 = @"http://opensum.in/app_test_f1/;";

你在 URL 字符串的末尾添加了一个 ;。

因此，当你连接两个字符串时，它会变成这样：http://opensum.in/app_test_f1/;45djx96.jpg

这不是一个有效的 URL。

正确的 URL 是：http://opensum.in/app_test_f1/45djx96.jpg

请修改代码如下：

 NSString *url_Img1 = @"http://opensum.in/app_test_f1/";

它会工作的。

- Midhun MP

谢谢，我改正了。但还是不起作用 -> view_Image.image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:url_Img_FULL"]]]; - Areeba Khan

@AreebaKhan：请检查您的view_Image不是空值。 - Midhun MP

@AreebaKhan：你是在同一个方法中将图像设置到view_Image吗？ - Midhun MP

0

如果你想要从URL显示图片，可以尝试这个方法...

 [ImageViewname setImageWithURL:[NSURL URLWithString:[NSString stringWithFormat:@"%@",your url]]];

如果想要从应用程序中本地显示图像，您可以尝试以下方法...

 ImageViewname.image = [UIImage imageNamed:@"test.png"];

我希望这能帮到你。愉快的编码...

- Bhrigesh

0

尝试使用AsyncImageView来满足您的需求，参考以下示例：

AsyncImageView

- Paras Joshi

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- Nookaraju · Accepted Answer

    NSString *url_Img1 = @"http://opensum.in/app_test_f1";
    NSString *url_Img2 = @"45djx96.jpg";

    NSString *url_Img_FULL = [url_Img1 stringByAppendingPathComponent:url_Img2];

    NSLog(@"Show url_Img_FULL: %@",url_Img_FULL);
    view_Image.image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:url_Img_FULL]]];

试一试。