獲取錯誤註釋從MapView的委託方法

Question

我宣佈我的.h文件中的以下內容：

Annotation *annoForMoreDetails。

然而，當我嘗試將其設置爲當前的註釋中

- (MKAnnotationView *)mapView:(MKMapView *)mapViews viewForAnnotation:(id <MKAnnotation>)annotation

它被設置爲錯誤的對象的方法。

這裏是我的代碼：

- (MKAnnotationView *)mapView:(MKMapView *)mapViews viewForAnnotation:(id <MKAnnotation>)annotation 
{ 
    NSLog(@"welcome into the map view annotation"); 
    // if it's the user location, just return nil. 
    if ([annotation isKindOfClass:[MKUserLocation class]]) 
     return nil; 
    for (annotation in [mapView annotations]) { 
     if ([[mapView annotations] containsObject:annotation]) { 
      annoForMoreDetails = annotation; 
     } 
    } 
    if (annoForMoreDetails.coordinate.latitude != mapViews.userLocation.coordinate.latitude && annoForMoreDetails.coordinate.longitude != mapViews.userLocation.coordinate.longitude) { 
    // try to dequeue an existing pin view first 
    static NSString* AnnotationIdentifier = @"AnnotationIdentifier"; 
    MKPinAnnotationView* pinView = [[[MKPinAnnotationView alloc] 
            initWithAnnotation:annotation reuseIdentifier:AnnotationIdentifier] autorelease]; 
    pinView.animatesDrop=YES; 
    pinView.canShowCallout=YES; 
    pinView.pinColor = MKPinAnnotationColorGreen; 

    UIButton* rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure]; 
    [rightButton setTitle:annotation.title forState:UIControlStateNormal]; 
    [rightButton addTarget:self 
        action:@selector(moreDetails) 
      forControlEvents:UIControlEventTouchUpInside]; 
    pinView.rightCalloutAccessoryView = rightButton; 
    return pinView; 
    } 
    else if (annoForMoreDetails.coordinate.latitude == mapViews.userLocation.coordinate.latitude && annoForMoreDetails.coordinate.longitude == mapViews.userLocation.coordinate.longitude) { 
     return nil; 
    } 
    return nil; 
} 

- (void)moreDetails { 
    annotationCalloutView.frame = CGRectMake(70, 120, 188, 218); 
    annotationCalloutView.alpha = 0.0; 
    mapView.userInteractionEnabled = NO; 
    annotationCalloutView.userInteractionEnabled = YES; 
    titleLabel.text = annoForMoreDetails.title; 
    titleLabel.numberOfLines = 0; 
    titleLabel.userInteractionEnabled = NO; 
    addressLabel.text = annoForMoreDetails.subtitle; 
    [self.view addSubview:annotationCalloutView]; 
    [UIView beginAnimations:@"callout" context:NULL]; 
    [UIView setAnimationDuration:0.6]; 
    annotationCalloutView.alpha = 1.0; 
    [UIView commitAnimations]; 
} 

如果你看到任何錯誤，請指出來！

Answer 1

您是否試圖使用annoForMoreDetails知道用戶點擊哪個註釋，以便顯示更多詳細信息？如果是這樣的話，還有一種更簡單的方法。使用地圖視圖的calloutAccessoryControlTapped委託方法。當用戶點擊附件按鈕時，它將被調用，並且它將通過包含註釋作爲屬性的註釋視圖。

刪除annoForMoreDetails實例變量，並在viewForAnnotation中，刪除設置annoForMoreDetails（我認爲它最終將它設置爲每次最後一個註釋）的for循環。刪除對annoForMoreDetails的所有其他引用。

而且在viewForAnnotation，卸下rightButton的addTarget行，因爲你會calloutAccessoryControlTapped的實現替換您的自定義moreDetails方法：

- (void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)view 
    calloutAccessoryControlTapped:(UIControl *)control 
{ 
    Annotation *annoForMoreDetails = (Annotation *)view.annotation; 

    //the code currently in moreDetails method goes here... 
}