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

Question

我想使用URL和NSString在UIImageView上显示图像。 我无法显示图像。

我的代码是：

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];               

这是我正在尝试的：

 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

但是我不想要这个，我想合并两个URL，使一个URL（即； url_Img_FULL），然后传递到如下图像：

UIImage *image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:url_Img_FULL]]]; // Not Working

我想要来自“ url_Img_FULL”（即：两个URL的组合）的图像将显示。 您也可以检查网址是否正常运行。 任何的想法？

Answer 1

    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]]]; 

尝试这个。

Answer 2

去做就对了

NSString *imgURL = @"imagUrl";

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

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

使用GCD：如果您不想挂起应用程序，则可以在后台下载图像。

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]];
    });    
});

Answer 3

对于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
}

Answer 4

从以下代码获取图像

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];

Answer 5

尝试这个

NSString* combinedString = [stringUrl1 stringByAppendingString stringUrl2];

Answer 6

对于Swift 3.0

同步：

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

异步地：

创建带有完成处理程序的方法以从您的网址获取图像数据

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()
}

创建下载图像的方法（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)
        }
    }
}

用法：

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.")
}

延期：

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()
    }
}

用法：

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.")

}

Answer 7

   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]];
    });    
});

Answer 8

根据您的要求尝试使用AsyncImageView，请参见以下示例

1. AsyncImageView

Answer 9

我测试了您的网址，发现了问题。

问题在于此行：

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

您正在添加; 网址字符串的最后。

因此，当您合并两个字符串时，它将看起来像： http://opensum.in/app_test_f1/;45djx96.jpg ://opensum.in/app_test_f1/;45djx96.jpg

这不是有效的网址。

正确的网址是： http://opensum.in/app_test_f1/45djx96.jpg : http://opensum.in/app_test_f1/45djx96.jpg

更改代码，例如：

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

会的

Answer 10

用于显示网址图片，您可以尝试以下操作...

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

用于从应用程序本地显示图像，您可以尝试...。

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

我希望这能帮到您。

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