界面布局 iOS RCTShadowView 和 yogaNode 建议映射 RCTUImanager 把 yoga 计算的布局结果同步到原生界面 RCTUImanager: setNeedsLayout > _layoutAndMount > [self addUIBlock:[self uiBlockWithLayoutUpdateForRootView:rootView]] > flushUIBlocksWithCompletion RCTUIManagerObserver 渲染生命周期监听 Android