From fb900f7d6665be174afc04ad10326aa856411ea9 Mon Sep 17 00:00:00 2001
From: faimin <fuxianchao@gmail.com>
Date: Sat, 17 Jul 2021 21:49:11 +0800
Subject: [PATCH] set view hierarchy lazily

---
 Source/Core/Public/UIView+ZDFlexLayout.m | 22 +-----------
 Source/Core/Public/ZDFlexLayout.m        | 22 ++++++++++++
 Source/Core/Public/ZDFlexLayoutDiv.m     | 43 ++++++------------------
 3 files changed, 34 insertions(+), 53 deletions(-)

diff --git a/Source/Core/Public/UIView+ZDFlexLayout.m b/Source/Core/Public/UIView+ZDFlexLayout.m
index 91da332..284bcbb 100644
--- a/Source/Core/Public/UIView+ZDFlexLayout.m
+++ b/Source/Core/Public/UIView+ZDFlexLayout.m
@@ -124,15 +124,7 @@ - (void)removeChild:(ZDFlexLayoutView)child {
     }
     
     [self.children removeObject:child];
-    
-    if ([child isKindOfClass:UIView.class]) {
-        [(UIView *)child removeFromSuperview];
-    }
-    else {
-        [child.children enumerateObjectsWithOptions:NSEnumerationReverse usingBlock:^(ZDFlexLayoutView  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
-            [child removeChild:obj];
-        }];
-    }
+
     
     child.parent = nil;
     child.owningView = nil;
@@ -164,18 +156,6 @@ - (void)insertChild:(ZDFlexLayoutView)child atIndex:(NSInteger)index {
     [self.children insertObject:child atIndex:mapedIndex];
     child.parent = self;
     child.owningView = self;
-    
-    if ([child isKindOfClass:UIView.class]) {
-        [self insertSubview:(UIView *)child atIndex:mapedIndex];
-    }
-    else {
-        for (ZDFlexLayoutView childChild in child.children) {
-            childChild.owningView = self;
-            if ([childChild isKindOfClass:UIView.class]) {
-                [self insertSubview:(UIView *)childChild atIndex:mapedIndex++];
-            }
-        }
-    }
 }
 
 - (void)removeFromParent {
diff --git a/Source/Core/Public/ZDFlexLayout.m b/Source/Core/Public/ZDFlexLayout.m
index 72f7568..f851869 100644
--- a/Source/Core/Public/ZDFlexLayout.m
+++ b/Source/Core/Public/ZDFlexLayout.m
@@ -502,6 +502,28 @@ static void YGApplyLayoutToViewHierarchy(ZDFlexLayoutView view, BOOL preserveOri
             [view needReApplyLayoutAtNextRunloop];
         }
     }
+    
+    ZDResetViewHierarchy(view);
+}
+
+/// lazy set view tree
+static void ZDResetViewHierarchy(ZDFlexLayoutView view)
+{
+    if (!view) {
+        return;
+    }
+    
+    UIView *superView = [view isKindOfClass:UIView.self] ? (UIView *)view : view.owningView;
+    NSCAssert(superView != nil, @"view can't be nil");
+    
+    for (ZDFlexLayoutView child in view.children) {
+        if ([child isKindOfClass:UIView.self]) {
+            [superView addSubview:(UIView *)child];
+        }
+        else {
+            ZDResetViewHierarchy(child);
+        }
+    }
 }
 
 static void ZD_Dispatch_sync_on_main_queue(dispatch_block_t block)
diff --git a/Source/Core/Public/ZDFlexLayoutDiv.m b/Source/Core/Public/ZDFlexLayoutDiv.m
index fbf717c..5764e1e 100644
--- a/Source/Core/Public/ZDFlexLayoutDiv.m
+++ b/Source/Core/Public/ZDFlexLayoutDiv.m
@@ -50,15 +50,6 @@ - (void)removeChild:(ZDFlexLayoutView)child {
     
     [self.children removeObject:child];
     
-    if ([child isKindOfClass:UIView.class]) {
-        [(UIView *)child removeFromSuperview];
-    }
-    else {
-        [child.children enumerateObjectsWithOptions:NSEnumerationReverse usingBlock:^(ZDFlexLayoutView  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
-            [child removeChild:obj];
-        }];
-    }
-    
     child.parent = nil;
 }
 
@@ -88,18 +79,6 @@ - (void)insertChild:(ZDFlexLayoutView)child atIndex:(NSInteger)index {
     [self.children insertObject:child atIndex:mapedIndex];
     child.parent = self;
     child.owningView = _owningView;
-    
-    if ([child isKindOfClass:UIView.class]) {
-        [_owningView insertSubview:(UIView *)child atIndex:mapedIndex];
-    }
-    else {
-        for (ZDFlexLayoutView childChild in child.children) {
-            childChild.owningView = child.owningView;
-            if ([childChild isKindOfClass:UIView.class]) {
-                [_owningView insertSubview:(UIView *)childChild atIndex:mapedIndex++];
-            }
-        }
-    }
 }
 
 - (void)removeFromParent {
@@ -193,17 +172,17 @@ - (void)addChildSubviews:(ZDFlexLayoutView)child {
     
     child.owningView = _owningView;
     
-    if ([child isKindOfClass:UIView.class]) {
-        [_owningView addSubview:(UIView *)child];
-    }
-    else {
-        for (ZDFlexLayoutView childChild in child.children) {
-            childChild.owningView = child.owningView;
-            if ([childChild isKindOfClass:UIView.class]) {
-                [_owningView addSubview:(UIView *)childChild];
-            }
-        }
-    }
+//    if ([child isKindOfClass:UIView.class]) {
+//        [_owningView addSubview:(UIView *)child];
+//    }
+//    else {
+//        for (ZDFlexLayoutView childChild in child.children) {
+//            childChild.owningView = child.owningView;
+//            if ([childChild isKindOfClass:UIView.class]) {
+//                [_owningView addSubview:(UIView *)childChild];
+//            }
+//        }
+//    }
 }
 
 @end