在 iOS 中从文件中获取图像

Posted 2023-02-23

【中文标题】在 iOS 中从文件中获取图像

【英文标题】：Get image from File in iOS

【发布时间】：2014-03-19 22:56:01

【问题描述】：

我试图从下载的文件中获取图像。首先，我获取图像并下载它们。

-(void)saveMoodImage

for (NSDictionary *dc in self.arrMood) 
    NSLog(@"dc: %@",dc);
    NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
    AFURLSessionManager *manager = [[AFURLSessionManager alloc] initWithSessionConfiguration:configuration];

    NSString *urlString = [NSString stringWithFormat:@"%@/images/%@",kRootUrl,dc[@"image"]];
    NSString* encodedUrl = [urlString stringByAddingPercentEscapesUsingEncoding:
                            NSUTF8StringEncoding];

    NSURL *URL = [NSURL URLWithString:encodedUrl];



    [[MUtility sharedObject].arrMoodImageUrl addObject:URL];
    [[MUtility sharedObject].arrMoodName addObject:dc[@"text"]];


    NSURLRequest *request = [NSURLRequest requestWithURL:URL];

    NSURLSessionDownloadTask *downloadTask = [manager downloadTaskWithRequest:request progress:nil destination:^NSURL *(NSURL *targetPath, NSURLResponse *response) 
        NSURL *documentsDirectoryPath = [NSURL fileURLWithPath:[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject]];
        return [documentsDirectoryPath URLByAppendingPathComponent:[response suggestedFilename]];
     completionHandler:^(NSURLResponse *response, NSURL *filePath, NSError *error) 

        NSLog(@"File downloaded to: %@", filePath);
        [[MUtility sharedObject].arrMoodImagePath addObject:filePath];


    ];
    [downloadTask resume];

结果日志：

2014-03-20 00:30:48.174 ImageTutorial[1124:60b] File downloaded to: file:///var/mobile/Applications/2HH213HGH-2389-4AF6-7328-ESD213AD343S/Documents/angry.png
2014-03-20 00:30:48.185 ImageTutorial[1124:60b] File downloaded to: file:///var/mobile/Applications/2HH213HGH-2389-4AF6-7328-ED0FAF04A97E/Documents/shine.png
2014-03-20 00:30:48.194 ImageTutorial[1124:60b] File downloaded to: file:///var/mobile/Applications/2HH213HGH-2389-4AF6-7328-ESD213AD343S/Documents/relaxed.png
2014-03-20 00:30:48.196 ImageTutorial[1124:60b] File downloaded to: file:///var/mobile/Applications/2HH213HGH-2389-4AF6-7328-ESD213AD343S/Documents/bored.png
2014-03-20 00:30:48.219 ImageTutorial[1124:60b] File downloaded to: file:///var/mobile/Applications/2HH213HGH-2389-4AF6-7328-ESD213AD343S/Documents/happy.png
2014-03-20 00:30:48.233 ImageTutorial[1124:60b] File downloaded to: file:///var/mobile/Applications/2HH213HGH-8322-4AF6-7328-ESD213AD343S/Documents/sick.png

然后我将图像设置为UIImageView

self.IV_test.image = [UIImage imageWithContentsOfFile:[NSString stringWithFormat:@"%@",[MUtility sharedObject].arrMoodImagePath[i]]]

最后，我无法设置图像。你有解决这个问题的办法吗？

【问题讨论】：

您是要创建一个新的 UIImageView 并将其放到屏幕上，还是只是更改屏幕上已经存在的 UIImageView 的图像？

我更改了代码，但它不再起作用了。

【参考方案1】：

您似乎将ImageView 与UIImage 混淆了。您正在将 UIImage 的实例分配给 UIImageView 变量。

UIImageView *imgView = [UIImage imageWithContentsOfFile:[NSString stringWithFormat:@"%@",[MUtility sharedObject].arrMoodImagePath[i]]]

您需要做的是如何获取屏幕上的视图实例并将图像分配给它。类似的东西

UIImageView *imgView = //... get instance from screen, alloc init, NIB, storyboard, ...
imgView.image = [UIImage imageWithContentsOfFile:[NSString stringWithFormat:@"%@",[MUtility sharedObject].arrMoodImagePath[i]]]

【参考方案2】：

把你的最后陈述分成几部分。将路径名提取为字符串。记录下来。

将该路径中的图像加载到局部变量中的 UIImage 中。记录下来。

然后，将图像安装到图像视图中。如果这不起作用，请检查您的图像视图属性是否为零。 （断开的出口链接是代码无法按预期工作的常见原因）