[WEEX-559][iOS]Fix issue that handleAppear should be resent for lazily created scrollview. (#1420)

Author: wqyfavor

ios/sdk/WeexSDK/Sources/Component/WXComponent_internal.h

@@ -264,6 +264,8 @@ typedef id (^WXDataBindingBlock)(NSDictionary *data, BOOL *needUpdate);
 
 - (void)_detachSlotEvent:(NSDictionary *)data;
 
+- (void)_buildViewHierarchyLazily;
+
 @end
 
 

ios/sdk/WeexSDK/Sources/Component/WXScrollerComponent.mm

@@ -229,8 +229,6 @@ - (void)viewDidLoad
 
 - (void)layoutDidFinish
 {
-
-    
     if ([self isViewLoaded]) {
         [self setContentSize:_contentSize];
         [self adjustSticky];
@@ -240,6 +238,12 @@ - (void)layoutDidFinish
     [_loadingComponent resizeFrame];
 }
 
+- (void)_buildViewHierarchyLazily
+{
+    [super _buildViewHierarchyLazily];
+    [self handleAppear];
+}
+
 - (void)viewWillUnload
 {
     ((UIScrollView *)_view).delegate = nil;