Question

我从UIImagePickerController获取UIImage，并保存它：

- (void) saveImageLocally:(UIImage *)image {
    NSData *imageData = UIImagePNGRepresentation(image);
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];

    NSString *imagePath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.png",@"A5UserAvatar"]];

    if (![imageData writeToFile:imagePath atomically:NO])
    {
        NSLog(@"Failed to cache image data to disk");
    }
    else
    {
        NSLog(@"the cachedImagedPath is %@", imagePath);
        [[NSUserDefaults standardUserDefaults] setObject:imagePath forKey:@"AvatarKey"];
        [[NSUserDefaults standardUserDefaults] synchronize];
    }
}

我可以在没有问题的情况下立即访问它：

- (UIImage *) getLocalImage {
    NSString *path = [[NSUserDefaults standardUserDefaults] stringForKey:@"AvatarKey"];
    NSLog(@"PATH FOR IMAGE IS %@", path);
    if (path != nil) {
        return [UIImage imageWithContentsOfFile:path];
    } else {
        return [UIImage imageNamed:@"default.gif"];
    }
}

上面的代码完全没有问题地返回保存的UIImage。

问题是，当我杀死应用程序并再次启动它时，找不到图像！我目前正在为iOS 7和8使用Xcode 6构建。我知道这个问题在模拟器中是不可避免的，但我也在现场设备上遇到它。

（见Xcode 6 keeps renaming my app's directory in iOS8 simulator after each run.）

我想知道我做错了什么，或者是否有另一种方法可以将任何图像作为文件存储在应用程序中，以便像化身一样使用。

Answer 1

问题是您要保存完整路径而不是相对于Documents文件夹的路径。由于应用程序路径可以更改，因此无法保存完整路径。

你想要这样的东西：

- (void) saveImageLocally:(UIImage *)image {
    NSData *imageData = UIImagePNGRepresentation(image);
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];

    NSString *filename = [NSString stringWithFormat:@"%@.png",@"A5UserAvatar"];
    NSString *imagePath = [documentsDirectory stringByAppendingPathComponent:filename];
    if (![imageData writeToFile:imagePath atomically:NO])
    {
        NSLog(@"Failed to cache image data to disk");
    }
    else
    {
        NSLog(@"the cachedImagedPath is %@", imagePath);
        [[NSUserDefaults standardUserDefaults] setObject:filename forKey:@"AvatarKey"];
        [[NSUserDefaults standardUserDefaults] synchronize];
    }
}

- (UIImage *) getLocalImage {
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];

    NSString *filename = [[NSUserDefaults standardUserDefaults] stringForKey:@"AvatarKey"];
    NSString *path = [documentsDirectory stringByAppendingPathComponent:filename];
    NSLog(@"PATH FOR IMAGE IS %@", path);
    if (path != nil) {
        return [UIImage imageWithContentsOfFile:path];
    } else {
        return [UIImage imageNamed:@"default.gif"];
    }
}

UIImage未保存在Documents目录中并终止应用程序

1 个答案: