我有以下代码来根据从我的服务器传递的数据创建我的所有注释，但有时没有任何“交易”或生成的引脚，所以当没有交易生成创建时我将如何做到这一点一个 UIAlertView？这是我必须到目前为止的代码：
- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation {
if([annotation isKindOfClass:[MKUserLocation class]]) {
return nil;
}
static NSString *identifier = @"MyLocation";
if ([annotation isKindOfClass:[Annotation class]]) {
MKPinAnnotationView *view = (MKPinAnnotationView *)[self.mapView dequeueReusableAnnotationViewWithIdentifier:identifier];
if (view == nil) {
view = [[MKPinAnnotationView alloc]
initWithAnnotation:annotation
reuseIdentifier:identifier];
UIAlertView *alert=[[UIAlertView alloc]initWithTitle:nil message:@"No Deals! Please Try Your Request Again!" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil];
[alert show];
} else {
view.annotation = annotation;
}
if([[(Annotation*)annotation phoneNumber] isEqualToString:@"0"]){
view.enabled = YES;
view.canShowCallout = YES;
view.pinColor = MKPinAnnotationColorPurple;
// Create a UIButton object to add on the
self.leftBtn = [UIButton buttonWithType:UIButtonTypeInfoDark];
[self.leftBtn setTitle:annotation.title forState:UIControlStateNormal];
view.rightCalloutAccessoryView = nil;
[view setLeftCalloutAccessoryView:self.leftBtn];
}else{
view.enabled = YES;
view.canShowCallout = YES;
// Create a UIButton object to add on the
self.rightBtn = [UIButton buttonWithType:UIButtonTypeInfoDark];
[self.rightBtn setTitle:annotation.title forState:UIControlStateNormal];
[view setRightCalloutAccessoryView:self.rightBtn];
}
if ([[(Annotation*)annotation phoneNumber] isEqualToString:@"1"]){
view.enabled = YES;
view.canShowCallout = YES;
view.pinColor = MKPinAnnotationColorGreen;
// Create a UIButton object to add on the
self.leftBtn = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
[self.leftBtn setTitle:annotation.title forState:UIControlStateNormal];
view.rightCalloutAccessoryView = nil;
[view setLeftCalloutAccessoryView:self.leftBtn];
}
return view;
}
return nil;
}
这是我必须在我的 http 请求方法中创建的东西吗？有任何想法吗？