UIImagePickerController Save to Disk then Load to UIImageView

最新推荐文章于 2017-05-26 12:20:33 发布

转载最新推荐文章于 2017-05-26 12:20:33 发布 · 1k 阅读

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#disk #image #object #path #file #date

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本文介绍了一个关于iOS应用中使用UIImagePickerController保存图片到本地并尝试加载到UIImageView时遇到的问题。作者详细描述了保存和加载图片的过程，并附上了相关代码。最终通过正确读取NSData并转换为UIImage的方式成功解决了图片无法显示的问题。

地址：http://stackoverflow.com/questions/2434324/uiimagepickercontroller-save-to-disk-then-load-to-uiimageview

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Hi,

I have a UIImagePickerController that saves the image to disk as a png. When I try to load the PNG and set a UIImageView's imageView.image to the file, it is not displaying.

Here is my code:

(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info { UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage]; NSData *imageData = UIImagePNGRepresentation(image);

// Create a file name for the image
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setTimeStyle:NSDateFormatterShortStyle];
[dateFormatter setDateStyle:NSDateFormatterShortStyle];
NSString *imageName = [NSString stringWithFormat:@"photo-%@.png",
                       [dateFormatter stringFromDate:[NSDate date]]];
[dateFormatter release];


// Find the path to the documents directory
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];


// Now we get the full path to the file
NSString *fullPathToFile = [documentsDirectory stringByAppendingPathComponent:imageName];


// Write out the data.
[imageData writeToFile:fullPathToFile atomically:NO];


// Set the managedObject's imageLocation attribute and save the managed object context
[self.managedObject setValue:fullPathToFile forKey:@"imageLocation"];
NSError *error = nil;
[[self.managedObject managedObjectContext] save:&error];


[self dismissModalViewControllerAnimated:YES];

}

Then here is how I try to load it:

self.imageView.backgroundColor = [UIColor lightGrayColor];
self.imageView.frame = CGRectMake(10, 10, 72, 72);
if ([self.managedObject valueForKey:@"imageLocation"] != nil) {
    NSLog(@"Trying to load the imageView with: %@", [self.managedObject valueForKey:@"imageLocation"]);
    UIImage *image = [[UIImage alloc] initWithContentsOfFile:[self.managedObject valueForKey:@"imageLocation"]];
    self.imageView.image = image;

} else {
    self.imageView.image = [UIImage imageNamed:@"no_picture_taken.png"];
}

I get the message that it's trying to load the imageView in the debugger, but the image is never displayed in the imageView. Can anyone tell me what I've got wrong here?

Thanks a bunch.

asked Mar 12 '10 at 16:54

Harley Gagrow
1 1

try not saving the full path, just the image name and look up the path before displaying. – Run Loop Mar 13 '10 at 3:45

1 Answer

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up vote 1 down vote

You're writing out an NSData object, not an image. You need to read the NSData object back in and convert to UIImage.

Assuming everything else is correct, try this:

NSData *data = [[NSData alloc] initWithContentsOfFile:[self.managedObject valueForKey:@"imageLocation"]];
UIImage *image = [[UIImage alloc] initWithData:data];