iphone - 如何在 ios 中使用 URL 和 NSString 在 UIImageView 上显示图像？

Question

我想在UIImageView 使用 URL 和NSString. 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

但我不想要这个我想连接两个 url 使一个 url(ie;url_Img_FULL) 然后传递给如下图像：

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）图像将显示。您还可以检查 url 是否正常工作。任何想法？

score 33 · 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]]];

尝试这个。

score 12 · Accepted Answer

去做就对了

NSString *imgURL = @"imagUrl";

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

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

使用 GCD：如果您不想挂起您的应用程序，那么您可以在后台下载您的图像。

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]];
    });    
});

score 2 · Accepted Answer

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
}

score 1 · Accepted Answer

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];

score 1 · Accepted Answer

1

尝试这个

NSString* combinedString = [stringUrl1 stringByAppendingString stringUrl2];

于 2012-11-23T11:49:16.977 回答

score 1 · Accepted Answer

   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]];
    });    
});

score 0 · Accepted Answer

我测试了您的网址并发现了问题。

问题在于这一行：

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

您正在添加;最后一个 url 字符串。

所以当你连接两个字符串时，它看起来像：http://opensum.in/app_test_f1/;45djx96.jpg

这不是一个有效的网址。

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

将代码更改为：

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

它会工作的。

score 0 · Accepted Answer

要从 url 显示图像，你可以试试这个......

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

要从应用程序本地显示图像，您可以试试这个....

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

我希望这能帮到您。

快乐的编码...

score 0 · Accepted Answer

0

为您的此要求尝试 AsyncImageView 请参阅此示例

异步图像视图

于 2012-11-23T11:34:39.840 回答

score 0 · Accepted Answer

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：

使用完成处理程序创建一个方法以从您的 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.")
}

扩大：

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.")

}

iphone - 如何在 ios 中使用 URL 和 NSString 在 UIImageView 上显示图像？

10 回答 10

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