【发布时间】：2018-08-26 22:53:15
【问题描述】：
我在使用 uiimagepickercontroller 时遇到了一个有趣的小问题，我想知道是否有人对可能发生的事情有任何见解。用户可以用相机拍照或从照片库中挑选，直到奶牛连续多次回家。我的问题在于允许用户恢复到应用程序附带的原始图像。这是流程：
- 用户转到显示图像缩略图的表格视图。
- 用户导航到显示图像更大视图的详细视图。
- 用户可以点击详细视图中的图像以调出自定义警报控制器，其中包含以下选项：a) 使用相机拍照，b) 使用其图库中的图片，或 c) 恢复为原始图像.
- 用户可以选择选项“a”或选项“b”来拍照或使用照片库中的照片。如果他们立即改变了使用其中一种选择的想法并只想回到使用原始图像，那么什么都不会发生！他们可以立即拍摄另一张照片或选择另一张图片，但无法立即恢复为原始图片。
当应用程序关闭然后再次打开时，恢复到原始图像确实可以正常工作。有时，如果您导航到应用程序中的其他视图，然后返回到他们刚刚添加自己图像的详细视图，它会起作用。为什么会延迟？我已经搜索了两周，但没有发现任何类似于我的问题或任何有帮助的解决方案（比如重新加载图像所在的标题视图）。有什么想法吗？
我还想出了如何使用文档将图像保存到 iCloud，但无法弄清楚如何检索它们，因此没有代码。那是完全不同的问题。即使没有该代码，似乎也会发生同样的事情。
感谢您抽出宝贵时间查看此内容！
这里有一些代码：
-(void)bookImageTapped:(UIGestureRecognizer *)gesture
{
URBAlertView *changeImageAlertView = [[URBAlertView alloc] initWithTitle:@"Add A New Book Cover Image" message:nil cancelButtonTitle:@"Cancel" otherButtonTitles:@"Use Camera", @"Open Gallery", @"Use Original Photo", nil];
[changeImageAlertView setHandlerBlock:^(NSInteger buttonIndex, URBAlertView *alertView) {
[self checkPermission];
if (PHAuthorizationStatusAuthorized)
{
if(buttonIndex == 0)
{
if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
{
[[NSOperationQueue mainQueue] addOperationWithBlock:^{
UIImagePickerController *pickerController = [[UIImagePickerController alloc] init];
pickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
pickerController.delegate = self;
pickerController.allowsEditing = NO;
pickerController.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];
[self presentViewController:pickerController animated:YES completion:nil];
}];
[alertView hide];
}
else
{
NSLog(@"Camera not available");
[alertView hide];
}
}
else if (buttonIndex == 1)
{
[[NSOperationQueue mainQueue] addOperationWithBlock:^{
UIImagePickerController *pickerController = [[UIImagePickerController alloc] init];
pickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
pickerController.delegate = self;
pickerController.allowsEditing = NO;
pickerController.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypePhotoLibrary];
[self presentViewController:pickerController animated:YES completion:nil];
}];
[alertView hide];
}
else if (buttonIndex == 2)
{
[[NSOperationQueue mainQueue] addOperationWithBlock:^{
[self restoreOriginalPhoto];
}];
[alertView hide];
}
else
{
NSLog(@"button 2 cancel");
[alertView hide];
}
}
}];
[changeImageAlertView show];
}
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(nonnull NSDictionary<NSString *,id> *)info
{
[picker dismissViewControllerAnimated:YES completion:nil];
_book.largeBookImage = [info objectForKey:UIImagePickerControllerOriginalImage];
_book.largeBookImage = [self scaleImage:_book.largeBookImage toSize:CGSizeMake(120, 168)];
_bookImageView.image = _book.largeBookImage;
_book.wasNewImageAdded = YES;
_book.originalImageUsed = NO;
NSString * documentsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
[self saveImage:_book.largeBookImage withFileName:_book.bookImageID ofType:@"jpg" inDirectory:documentsDirectory];
}
-(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
[picker dismissViewControllerAnimated:YES completion:nil];
}
-(void)saveImage:(UIImage *)image withFileName:(NSString *)imageName ofType:(NSString *)extension inDirectory:(NSString *)directoryPath
{
if ([[extension lowercaseString] isEqualToString:@"png"])
{
[UIImagePNGRepresentation(image) writeToFile:[directoryPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.%@", imageName, @"png"]] options:NSAtomicWrite error:nil];
//Create a URL to the local file
NSURL *resourceURL = [NSURL fileURLWithPath:[directoryPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.%@", imageName, @"png"]]];
if (resourceURL)
{
CKAsset *asset = [[CKAsset alloc] initWithFileURL:resourceURL];
//create a record object
CKRecord *bookCover = [[CKRecord alloc] initWithRecordType:@"Bookcover"];
//set the record's fields
bookCover[@"title"] = _book.title;
bookCover[@"bookImage"] = asset;
/* TO SAVE A RECORD */
//get the public database
CKContainer *appContainer = [CKContainer defaultContainer];
CKDatabase *publicDatabase = [appContainer publicCloudDatabase];
[publicDatabase saveRecord:bookCover completionHandler:^(CKRecord *bookCover, NSError *error) {
if (error)
{
//insert error handling
return;
}
//insert succesfully saved record code
NSLog(@"png record saved after using picker!");
}];
}
}
else if ([[extension lowercaseString] isEqualToString:@"jpg"] || [[extension lowercaseString] isEqualToString:@"jpeg"])
{
[UIImageJPEGRepresentation(image, 1.0) writeToFile:[directoryPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.%@", imageName, @"jpg"]] options:NSAtomicWrite error:nil];
//Create a URL to the local file
NSURL *resourceURL = [NSURL fileURLWithPath:[directoryPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.%@", imageName, @"jpg"]]];
if (resourceURL)
{
CKAsset *asset = [[CKAsset alloc] initWithFileURL:resourceURL];
//create a record object
CKRecord *bookCover = [[CKRecord alloc] initWithRecordType:@"Bookcover"];
//set the record's fields
bookCover[@"title"] = _book.title;
bookCover[@"bookImage"] = asset;
/* TO SAVE A RECORD */
//get the public database
CKContainer *appContainer = [CKContainer defaultContainer];
CKDatabase *publicDatabase = [appContainer publicCloudDatabase];
[publicDatabase saveRecord:bookCover completionHandler:^(CKRecord *bookCover, NSError *error) {
if (error)
{
//insert error handling
return;
}
//insert succesfully saved record code
NSLog(@"jpg record saved after using picker!");
}];
}
}
else
{
NSLog(@"Image Save Failed\nExtension: (%@) is not recognized, use (PNG/JPG)", extension);
}
}
- (UIImage *) scaleImage:(UIImage*)image toSize:(CGSize)newSize
{
UIGraphicsBeginImageContextWithOptions(newSize, NO, 0.0);
[image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
-(void)restoreOriginalPhoto
{
NSLog(@"restore photo called");
_book.originalImageUsed = YES;
_book.wasNewImageAdded = NO;
_bookImageView.image = _book.largeBookImage;
NSString * documentsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
[self saveImage:_book.largeBookImage withFileName:_book.bookImageID ofType:@"jpg" inDirectory:documentsDirectory];
}
这是带有图像视图的标题视图：
-(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
_headerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, tableView.frame.size.width, 26)];
_headerView.backgroundColor = [UIColor colorWithRed:8/255.0 green:46/255.0 blue:46/255.0 alpha:0.8];
if (section == 0)
{
_headerView.backgroundColor = [UIColor whiteColor];
_bookImageView = [[UIImageView alloc] initWithFrame:CGRectMake((tableView.frame.size.width - 120)/2, 6, 120, 168)];
_bookImageView.contentMode = UIViewContentModeScaleAspectFit;
if (_book.wasNewImageAdded)
{
NSString * documentsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
UIImage * image = [self loadImageWithFileName:_book.bookImageID ofType:@"jpg" inDirectory:documentsDirectory];
_bookImageView.image = image;
}
else
{
_bookImageView.image = _book.largeBookImage;
}
if(_book.originalImageUsed)
{
NSString * documentsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
UIImage * image = [self loadImageWithFileName:_book.bookImageID ofType:@"jpg" inDirectory:documentsDirectory];
_bookImageView.image = image;
}
UITapGestureRecognizer *bookImageTouched = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(bookImageTapped:)];
bookImageTouched.numberOfTapsRequired = 1;
[_bookImageView addGestureRecognizer:bookImageTouched];
_bookImageView.userInteractionEnabled = YES;
[_headerView addSubview:_bookImageView];
}
【问题讨论】：
标签： ios objective-c uiimageview uiimagepickercontroller