求助： ios 如何用 NSTextattAchment 加载 SDWebImage 下载下来的图片

[lufir]

代码如下：
```objc

UITextView *textView = [[UITextView alloc] initWithFrame:CGRectMake (0, 20, self.view.frame.size.width, self.view.frame.size.height-20 )];
[self.view addSubview:textView];

UIImageView *imageView = [[UIImageView alloc] init];
[imageView sd_setImageWithURL:[NSURL URLWithString:@"http://7bv920.com1.z0.glb.clouddn.com/20150901.jpg"]];

NSTextAttachment *attachment = [[NSTextAttachment alloc] initWithData:nil ofType:nil];
attachment.image = imageView.image;
attachment.bounds = CGRectMake (0, 20, self.view.frame.size.width, 300 );
NSMutableAttributedString *attStr = [[NSMutableAttributedString alloc] initWithAttributedString:textView.attributedText];
NSAttributedString *imageStr = [NSAttributedString attributedStringWithAttachment:attachment];
[attStr appendAttributedString:imageStr];
textView.attributedText = attStr;

1.图片加载是正确的，如果直接将 imageview 显示在 self.view 上可以显示。
2.用 NSTextAttachment 直接加载一张本地图片也可以正常显示
3.用 NSTextattAchment 加载 imageview.image 就无法显示了

---求助各路大神

[wujichao]

哥们你是新手吧 下载是异步的, 这时候 image 还没下好呢