iOS學習_ESRI iOS SDK_AGSMapView MapLayer的控制

一般利用ESRI SDK開發相關的地圖應用程式，最常使用的三種圖層類別，莫過於TiledMapService、DynamicMapService與Graphics，而對應到iOS當中的定義分別為：

*AGSTiledMapServiceLayer
*AGSDynamicMapServiceLayer
*AGSGraphicsLayer

加入地圖的方法：
AGSTiledMapServiceLayer

AGSTiledMapServiceLayer *tiledLayer = [[AGSTiledMapServiceLayer alloc] initWithURL:[NSURL URLWithString:kTiledMapServiceURL]];
[self.mapView addMapLayer:tiledLayer withName:@"ola Tile"];


AGSDynamicMapServiceLayer

self.dynamicLayer = [[[AGSDynamicMapServiceLayer alloc] initWithURL:[NSURL URLWithString:kDynamicMapServiceURL]];
NSArray *layerArray = [NSArray arrayWithObjects:[NSNumber numberWithInt:26],nil];
self.dynamicLayer.visibleLayers = layerArray;
[self.mapView addMapLayer:self.dynamicLayer withName:@"ola Dynamic"];


AGSGraphicsLayer

self.olagraphic = [AGSGraphicsLayer graphicsLayer];
[self.mapView addMapLayer:self.olagraphic withName:@"olagraphicsLayer"];


總之，不管是要加入那一種圖層，都是使用addMapLayer的方法，而在使用該方法時，都回返回一個UIView，如果想要一開始就設定透明度與顯示與否，就可以在接下來後設定alpha或是hidden的屬性。

UIView *dynamicLayerView = [self.mapView addMapLayer:self.dynamicLayer withName:@"Dynamic Layer"];
dynamicLayerView.alpha = 0.5;
dynamicLayerView.hidden = NO;


有時候我們可以會想要知道mapView到底目前有哪些圖層，就可以藉由mapLayers方法取得圖層列表，利用mapLayerViews方法取得圖層視圖。

NSArray *layerLists = [self.mapView mapLayers];
AGSDynamicMapServiceLayer *layerGroup = [layerLists objectAtIndex:i];

NSDictionary *layerLists = [self.mapView mapLayerViews];
dynamicLayerView = [layerLists objectForKey:@"ola Dynamic"];


取得對應的dynamicLayerView後，就可以動態的改變是否顯示與透明度。