使用照片框架将图像保存到照片库
Save image to photo library using photo framework
每次尝试使用照片框架保存图像时,我的应用程序都会崩溃。
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{
_mChangeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:[info valueForKey:UIImagePickerControllerOriginalImage]];
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
_mChangeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:[info valueForKey:UIImagePickerControllerOriginalImage]];
} completionHandler:^(BOOL success, NSError *error) {
if (success) {
PHObjectPlaceholder *assetPlaceholder = _mChangeRequest.placeholderForCreatedAsset;
}
else {
NSLog(@"write error : %@",error);
}
}];
}
crash : NSInternalInconsistencyException', reason: 'This method can only be called from inside of -[PHPhotoLibrary performChanges:completionHandler:] or -[PHPhotoLibrary performChangesAndWait:error:]'
- 删除第三行代码
- 验证 _mChangeRequest 是 __block 变量
- 编译和运行
您将在照片应用程序中看到该图像
您可能会像这样更改代码...
- (void)imagePickerController:(UIImagePickerController *)picker
didFinishPickingMediaWithInfo:(NSDictionary *)info {
__block PHAssetChangeRequest *_mChangeRequest = nil;
[[PHPhotoLibrary sharedPhotoLibrary]
performChanges:^{
UIImage *image = [info valueForKey:UIImagePickerControllerOriginalImage];
_mChangeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:image];
}, completionHandler :^(BOOL success, NSError *error) {
if (success) {
PHObjectPlaceholder *assetPlaceholder = _mChangeRequest.placeholderForCreatedAsset;
} else {
NSLog(@"write error : %@", error);
}
}];
}
您需要做的就是触发创建请求。如错误所述,您只能在 performChanges
块内访问更改请求。
因此,要保存图像,您需要执行以下操作:
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
[PHAssetChangeRequest creationRequestForAssetFromImage:[info valueForKey:UIImagePickerControllerOriginalImage]];
} completionHandler:^(BOOL success, NSError *error) {
if (success) {
NSLog(@"Success");
}
else {
NSLog(@"write error : %@",error);
}
}];
如果您需要对新创建的资产的占位符进行操作,您可以在同一个 performChanges
块中访问它:
PHAssetChangeRequest *changeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:[info valueForKey:UIImagePickerControllerOriginalImage]];
PHObjectPlaceholder *assetPlaceholder = changeRequest.placeholderForCreatedAsset;
在 Swift 3 我这样做是为了将视频保存到库中。
if mediaType.isEqual(to: (kUTTypeMovie as NSString) as String) {
if let videoURL = info[UIImagePickerControllerMediaURL] as? URL {
PHPhotoLibrary.shared().performChanges({
_ = PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: videoURL)
}, completionHandler: { (success, error) in
if success {
print("ok")
let videoData = NSData(contentsOf: videoURL)
// use videoData here if needed...
if let posterImage = self.firstFrame(videoURL: videoURL) {
self.imageView.image = posterImage
}
picker.dismiss(animated: true) { () -> Void in
}
} else {
print(error?.localizedDescription)
}
})
}
}
这是一个代码示例,您可以如何使用 UIImageWriteToSavedPhotosAlbum
函数将 write/save 图像添加到照片库:
- (void)saveImage:(UIImage *)image {
UIImageWriteToSavedPhotosAlbum(self.image, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
}
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo;
{
if (!error) {
// saved successfully
PHFetchOptions *fetchOptions = [PHFetchOptions new];
fetchOptions.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:NO]];
PHAsset *asset = [PHAsset fetchAssetsWithMediaType:PHAssetMediaTypeImage options:fetchOptions].firstObject;
if (asset != nil) {
// here you can use asset of your image
}
} else {
NSLog(@"save image error: %@", error);
}
}
不要忘记在您的 Info.plist
中添加键值对 Privacy - Camera Usage Description
以及使用说明。
每次尝试使用照片框架保存图像时,我的应用程序都会崩溃。
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{
_mChangeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:[info valueForKey:UIImagePickerControllerOriginalImage]];
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
_mChangeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:[info valueForKey:UIImagePickerControllerOriginalImage]];
} completionHandler:^(BOOL success, NSError *error) {
if (success) {
PHObjectPlaceholder *assetPlaceholder = _mChangeRequest.placeholderForCreatedAsset;
}
else {
NSLog(@"write error : %@",error);
}
}];
}
crash : NSInternalInconsistencyException', reason: 'This method can only be called from inside of -[PHPhotoLibrary performChanges:completionHandler:] or -[PHPhotoLibrary performChangesAndWait:error:]'
- 删除第三行代码
- 验证 _mChangeRequest 是 __block 变量
- 编译和运行
您将在照片应用程序中看到该图像
您可能会像这样更改代码...
- (void)imagePickerController:(UIImagePickerController *)picker
didFinishPickingMediaWithInfo:(NSDictionary *)info {
__block PHAssetChangeRequest *_mChangeRequest = nil;
[[PHPhotoLibrary sharedPhotoLibrary]
performChanges:^{
UIImage *image = [info valueForKey:UIImagePickerControllerOriginalImage];
_mChangeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:image];
}, completionHandler :^(BOOL success, NSError *error) {
if (success) {
PHObjectPlaceholder *assetPlaceholder = _mChangeRequest.placeholderForCreatedAsset;
} else {
NSLog(@"write error : %@", error);
}
}];
}
您需要做的就是触发创建请求。如错误所述,您只能在 performChanges
块内访问更改请求。
因此,要保存图像,您需要执行以下操作:
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
[PHAssetChangeRequest creationRequestForAssetFromImage:[info valueForKey:UIImagePickerControllerOriginalImage]];
} completionHandler:^(BOOL success, NSError *error) {
if (success) {
NSLog(@"Success");
}
else {
NSLog(@"write error : %@",error);
}
}];
如果您需要对新创建的资产的占位符进行操作,您可以在同一个 performChanges
块中访问它:
PHAssetChangeRequest *changeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:[info valueForKey:UIImagePickerControllerOriginalImage]];
PHObjectPlaceholder *assetPlaceholder = changeRequest.placeholderForCreatedAsset;
在 Swift 3 我这样做是为了将视频保存到库中。
if mediaType.isEqual(to: (kUTTypeMovie as NSString) as String) {
if let videoURL = info[UIImagePickerControllerMediaURL] as? URL {
PHPhotoLibrary.shared().performChanges({
_ = PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: videoURL)
}, completionHandler: { (success, error) in
if success {
print("ok")
let videoData = NSData(contentsOf: videoURL)
// use videoData here if needed...
if let posterImage = self.firstFrame(videoURL: videoURL) {
self.imageView.image = posterImage
}
picker.dismiss(animated: true) { () -> Void in
}
} else {
print(error?.localizedDescription)
}
})
}
}
这是一个代码示例,您可以如何使用 UIImageWriteToSavedPhotosAlbum
函数将 write/save 图像添加到照片库:
- (void)saveImage:(UIImage *)image {
UIImageWriteToSavedPhotosAlbum(self.image, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
}
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo;
{
if (!error) {
// saved successfully
PHFetchOptions *fetchOptions = [PHFetchOptions new];
fetchOptions.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:NO]];
PHAsset *asset = [PHAsset fetchAssetsWithMediaType:PHAssetMediaTypeImage options:fetchOptions].firstObject;
if (asset != nil) {
// here you can use asset of your image
}
} else {
NSLog(@"save image error: %@", error);
}
}
不要忘记在您的 Info.plist
中添加键值对 Privacy - Camera Usage Description
以及使用说明。