iPhone - UIImagePickerController ->将图像保存到应用程序文件夹

Question

我有一个使用 UIImagePickerController 的 iPhone 应用程序。作为 sourceType 我有

• UIImagePickerControllerSourceTypePhotoLibrary
• UIImagePickerControllerSourceTypeCamera
• UIImagePickerControllerSourceTypeSavedPhotosAlbum

，因此用户可以制作照片或从照片或相机照片中的照片库中选择一张照片。

图像将显示在 UIImageView 中。如果用户关闭应用程序，则应保存图像。因此，对于文本字段，我使用 NSUserDefaults。我知道，用 NSData 将图像保存在 NSUSerDefaults 中并不是一个好方法，所以我想将图像保存/复制到由我的应用程序控制的文件夹中，类似于 NSUserDefaults。

我该怎么做？我想保存它，然后我可以将文件的路径写入我的 NSUserDefaults 并在应用程序启动时读取它。

预先感谢您&此致。

Answer 1

中使用以下代码

- (void) imagePickerController:(UIImagePickerController *)picker
 didFinishPickingMediaWithInfo:(NSDictionary *)info {

    //obtaining saving path
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *imagePath = [documentsDirectory stringByAppendingPathComponent:@"latest_photo.png"];

    //extracting image from the picker and saving it
    NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];   
    if ([mediaType isEqualToString:@"public.image"]){
        UIImage *editedImage = [info objectForKey:UIImagePickerControllerEditedImage];
        NSData *webData = UIImagePNGRepresentation(editedImage);
        [webData writeToFile:imagePath atomically:YES];
    }
}

您可以在 XueYu 的 UIImagePickerControllerDelegate 委托实现UPD

Swift 3.0 代码

此处图像保存为 jpeg，但您也可以将其保存为 png。这
0.0参数代表压缩，它是最低质量，如果你想得到最好的使用1.0。

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {

    //obtaining saving path
    let fileManager = FileManager.default
    let documentsPath = fileManager.urls(for: .documentDirectory, in: .userDomainMask).first
    let imagePath = documentsPath?.appendingPathComponent("image.jpg")

    // extract image from the picker and save it
    if let pickedImage = info[UIImagePickerControllerOriginalImage] as? UIImage {
        try! UIImageJPEGRepresentation(pickedImage, 0.0)?.write(to: imagePath!)
    }
    self.dismiss(animated: true, completion: nil)        
}

Answer 2

根据您要保存的文件格式，您可以使用

[UIImagePNGRepresentation(image) writeToFile:path atomically:YES];

OR

[UIImageJPEGRepresentation(image) writeToFile:path atomically:YES];

Answer 3

这是将 UIImage 保存到文档目录中的代码。您可以在 didFinishPickingImage 委托方法中使用此代码：

// Create paths to output images
NSString  *pngPath = [NSHomeDirectory();
stringByAppendingPathComponent:@"Documents/Test.png"];
NSString  *jpgPath = [NSHomeDirectory();
stringByAppendingPathComponent:@"Documents/Test.jpg"];

// Write a UIImage to JPEG with minimum compression (best quality)
// The value 'image' must be a UIImage object
// The value '1.0' represents image compression quality as value from 0.0 to 1.0
[UIImageJPEGRepresentation(image, 1.0) writeToFile:jpgPath atomically:YES];

// Write image to PNG
[UIImagePNGRepresentation(image) writeToFile:pngPath atomically:YES];

// Let's check to see if files were successfully written...

// Create file manager
NSError *error;
NSFileManager *fileMgr = [NSFileManager defaultManager];

// Point to Document directory
NSString *documentsDirectory = [NSHomeDirectory();
stringByAppendingPathComponent:@"Documents"];

// Write out the contents of home directory to console
NSLog(@"Documents directory: %@", [fileMgr contentsOfDirectoryAtPath:documentsDirectory error:&error]);

编辑

您还可以使用：

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

查找应用程序文档目录的路径，而不是 NSHomeDierctory。

Answer 4

更新 knuku 对 Swift 3.0 的答案

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {

    //obtaining saving path
    let fileManager = FileManager.default
    let documentsPath = fileManager.urls(for: .documentDirectory, in: .userDomainMask).first
    let imagePath = documentsPath?.appendingPathComponent("image.jpg")

    // extract image from the picker and save it
    if let pickedImage = info[UIImagePickerControllerOriginalImage] as? UIImage {
        try! UIImageJPEGRepresentation(pickedImage, 0.0)?.write(to: imagePath!)
    }
    self.dismiss(animated: true, completion: nil)        
}

，此处图像保存为 jpeg，但您也可以将其保存为 png。 0.0 参数代表压缩，它是最低质量，如果您想获得最佳效果，请使用 1.0。