iphone - MKAnnotationn leftcalloutaccessoryview 没有得到刷新

Question

我正在尝试从 URL 添加图像到。我正在使用线程来加载图像。我将 MKAnnotationView 对象传递给另一个方法并在该方法中加载图像。当我第一次单击注释时，图像正在加载但未显示在注释上，但是当我第二次单击时它显示了。我找不到错误是什么。

-(void)mapView:(MKMapView *)mapView didSelectAnnotationView:(MKAnnotationView *)view
{
    NSLog(@"Selected View Tag = %d", view.tag);
    UIImageView *imaged = [[UIImageView alloc]initWithFrame:CGRectMake(0,0,31,31)];
   act = [[UIActivityIndicatorView alloc]initWithFrame:CGRectMake(0,0,31,31)];

    [act startAnimating];
    [imaged addSubview:act];



    view.leftCalloutAccessoryView = imaged;

    [NSThread detachNewThreadSelector:@selector(threadaimage:) toTarget:self withObject:view];



}
-(void)threadaimage:(MKAnnotationView*)imageview1
{

    NSLog(@"Selected Tag in Thread Method = %d",imageview1.tag);


    UIButton *imag = [[UIButton alloc]init];
    imag.frame = CGRectMake(0, 0, 31, 31);
    NSData *imageData = [NSData dataWithContentsOfURL:
                                                  [NSURL URLWithString:[image_arr objectAtIndex:imageview1.tag]]];
    NSLog(@"%@",[image_arr objectAtIndex:imageview1.tag]);

    [imag setImage:[UIImage imageWithData:imageData] forState:UIControlStateNormal];
    [self.view addSubview:imag];
    imageview1.leftCalloutAccessoryView = imag;
    [act stopAnimating];
}

Answer 1

好吧，我想我终于为你弄明白了:)

我所做的是 - 我创建了一个按钮，将 activityIndi​​cator 作为 subview 添加到它，当有图像下载时，我将图像设置到同一个按钮。并删除事件指示器。在我身边工作。这是我最终得到的代码:

-(void)mapView:(MKMapView *)mapView didSelectAnnotationView:(MKAnnotationView *)view
{
    UIButton *customAccessoryButton = [UIButton buttonWithType:UIButtonTypeCustom];

    customAccessoryButton.frame = CGRectMake(0, 0, 31, 31);


    act = [[UIActivityIndicatorView alloc]initWithFrame:CGRectMake(0,0,31,31)];

    [act startAnimating];

    [customAccessoryButton addSubview:act];

    view.leftCalloutAccessoryView = customAccessoryButton;

    [NSThread detachNewThreadSelector:@selector(threadaimage:) toTarget:self withObject:view];
}


- (void)threadaimage:(MKAnnotationView*)imageview1
{
    UIButton *customAccessoryButton = (UIButton*)imageview1.leftCalloutAccessoryView;

    NSData *imageData = [NSData dataWithContentsOfURL:
        [NSURL URLWithString:@"http://www.gemini.edu/images/stories/press_release/pr2008-6/fig1.jpg"]];

    [customAccessoryButton setImage:[UIImage imageWithData:imageData] forState:UIControlStateNormal];

    [act removeFromSuperview];

    [act stopAnimating];
}