Objective c UIActivityIndicator从联机加载图像时查看?
我有一个简单的脚本,它显示在互联网上的UIImageView中 有没有办法显示UIActivityIndicatorView或类似的东西,向用户显示它正在加载 以下是我的最低代码:Objective c UIActivityIndicator从联机加载图像时查看?,objective-c,xcode,ios4,uiimageview,uiimage,Objective C,Xcode,Ios4,Uiimageview,Uiimage,我有一个简单的脚本,它显示在互联网上的UIImageView中 有没有办法显示UIActivityIndicatorView或类似的东西,向用户显示它正在加载 以下是我的最低代码: NSString *imagePath = [NSString stringWithFormat:@"urlofimagehere.jpg"]; NSData *mydata = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:imagePath]
NSString *imagePath = [NSString stringWithFormat:@"urlofimagehere.jpg"];
NSData *mydata = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:imagePath]];
UIImage *myimage = [[UIImage alloc] initWithData:mydata];
[imageView setImage:myimage];
[myimage release];
谢谢!
库尔顿
编辑:删除代码
-[NSData initWithContentsOfURL:]
是一种同步方法。这意味着它将阻塞,直到数据通过网络加载。如果您希望能够保持UI的响应性,则需要使用异步方法。有关更多信息,请阅读以下内容:
我建议将NSURLRequest与NSURLRequestDelegate一起使用,以便在数据加载完成时接收回调。下面是一个例子:
- (void)loadImageAtURL(NSString *)urlString {
[myUIActivityIndicatorView startAnimating];
// SHOW NETWORK INDICATOR
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
// SET UP THE REQUEST
NSURL *url = [[NSURL alloc] initWithString:urlString];
NSURLRequest *request = [[[NSURLRequest alloc] initWithURL:url] autorelease];
// SET UP THE CONNECTION
connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
mutData = [[[NSMutableData alloc] init] retain];
}
- (void)connection:(NSURLConnection *)connection
didFailWithError:(NSError *)error {
// Handle error
}
- (void)connection:(NSURLConnection *)connection
didReceiveData:(NSData *)data {
[mutData appendData:data];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)aConnection {
// ONCE LOADED HIDE NETWORK INDICATOR
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
// RELEASE THE CONNECTION
[connection release];
// CREATE NEW UIIMAGE FROM THE DATA
image = [[[UIImage alloc] initWithData:mutData] retain];
[mutData release];
// HIDE THE ACTIVITY INDICATOR
// Make sure hidesWhenStopped is set to YES on the activity indicator.
[myUIActivityIndicatorView stopAnimating];
[myUIImageView setImage:image];
[image release];
}
希望这有帮助 我试过了,但失败了。请看我更新的帖子!谢谢。可能有很多错误,在我发布之前我真的没有检查过。再次感谢!PS:这一行失败:
NSURLRequest*请求=[[[NSURLRequest alloc]initWithURL:imagePath]autorelease]代码>。我道歉。initWithURL接受NSURL,而不是NSString。您需要使用-[NSURL initWithString:]参见上面修改的答案。