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IOS 保存图片至相册

 

IOS 保存图片至相册

 
应用中有时我们会有保存图片的需求,如利用UIImagePickerController用IOS设备内置的相机拍照,或是有时我们在应用程序中利用UIKit的 UIGraphicsBeginImageContext,UIGraphicsEndImageContext,UIGraphicsGetImageFromCurrentImageContext方法创建一张图像需要进行保存。 IOS的UIKit Framework提供了UIImageWriteToSavedPhotosAlbum方法对图像进行保存,该方法会将image保存至用户的相册中,描述如下: 
1void UIImageWriteToSavedPhotosAlbum (
2   UIImage  *image,
3   id       completionTarget,
4   SEL      completionSelector,
5   void     *contextInfo
6);
参数说明: 
        image 
            带保存的图片UImage对象 

        completionTarget 
            图像保存至相册后调用completionTarget指定的selector(可选) 

        completionSelector 
                completionTarget的方法对应的选择器,相当于回调方法,需满足以下格式 
1- (void) image: (UIImage *) image
2didFinishSavingWithError: (NSError *) error
3             contextInfo: (void *) contextInfo;
         contextInfo指定了在回调中可选择传入的数据。 

 

当我们需要异步获得图像保存结果的消息时,我们需要指定completionTarget对象以及其completionSelector对应的选择器。示例如下:  

 

01- (void)saveImageToPhotos:(UIImage*)savedImage
02{
03    UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL); 
04}
05// 指定回调方法
06- (void)image: (UIImage *) image didFinishSavingWithError: (NSError *) error contextInfo: (void *) contextInfo
07{  
08    NSString *msg = nil ;  
09    if(error != NULL){
10        msg = @"保存图片失败" ;
11    }else{
12        msg = @"保存图片成功" ;
13    }
14    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"保存图片结果提示"
15                                                        message:msg
16                                                       delegate:self
17                                              cancelButtonTitle:@"确定"
18                                              otherButtonTitles:nil];
19    [alert show];
20}
21 
22// 调用示例
23UIImage *savedImage = [UIImage imageNamed:"savedImage.png"];
24 
25[self saveImageToPhotos:savedImage];

IOS 保存图片至相册