Question

我有一个问题。是否可以打印仅暂时保存的图像？我在图像溢出的问题example中完成了保存图像。

但是，当我尝试使用此图片通过AirPrint进行打印时，它无效。

- (IBAction)btnPrintTapped:(id)sender {

    UIImage* image = nil;

    UIGraphicsBeginImageContext(_scrollView.contentSize);
    {
        CGPoint savedContentOffset = _scrollView.contentOffset;
        CGRect savedFrame = _scrollView.frame;

        _scrollView.contentOffset = CGPointZero;
        _scrollView.frame = CGRectMake(0, 0, _scrollView.contentSize.width, _scrollView.contentSize.height);

        [_scrollView.layer renderInContext: UIGraphicsGetCurrentContext()];
        image = UIGraphicsGetImageFromCurrentImageContext();

        _scrollView.contentOffset = savedContentOffset;
        _scrollView.frame = savedFrame;
    }
    UIGraphicsEndImageContext();

    if (image != nil) {
        [UIImagePNGRepresentation(image) writeToFile: @"/tmp/test.png" atomically: YES];
        UIImage *yourImage = [UIImage imageNamed:@"/tmp/test.png"];
        NSArray *itemsToShare = @[yourImage];
        UIActivityViewController *activityVC = [[UIActivityViewController alloc] initWithActivityItems:itemsToShare applicationActivities:nil];
        activityVC.excludedActivityTypes = @[ UIActivityTypeCopyToPasteboard, UIActivityTypeAssignToContact, UIActivityTypeSaveToCameraRoll, UIActivityTypeMail, UIActivityTypeMessage, UIActivityTypePostToFacebook, UIActivityTypePostToTwitter, UIActivityTypePostToWeibo]; 
        [self presentViewController:activityVC animated:YES completion:nil];
    }    
}

但打印机能够打印（我用修复图像对其进行了测试）......所以打印机似乎不是问题所在。感谢您的帮助。

更新我对代码做了一些更改/添加了一些代码行：

[UIImagePNGRepresentation(image) writeToFile: @"/tmp/test.png" atomically: YES];

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString* path = [documentsDirectory stringByAppendingPathComponent:@"/tmp/test.png" ];
UIImage* image = [UIImage imageWithContentsOfFile:path];

UIImage *ImageItem = image;

但它仅在我设置writeToFile: @"test.png"时有效...但是我只能保存一次图像而不会覆盖它。

当我使用上面的代码时，有一个错误：

由于未捕获的异常'NSInvalidArgumentException'而终止应用程序，原因：' - [__ NSPlaceholderArray initWithObjects：count：]：尝试从对象[0]中插入nil对象

Answer 1

经过一番尝试后，它终于有效了......

if (image != nil) {
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
                                                             NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0];
        NSString* path = [documentsDirectory stringByAppendingPathComponent:
                          @"test.png" ];
        NSData* data = UIImagePNGRepresentation(image);
        [data writeToFile:path atomically:YES];


        UIImage* image = [UIImage imageWithContentsOfFile:path];
        UIImage *yourImage = image;

通过AirPrint打印临时保存的图像

1 个答案: