我正在使用Facebook ComponentsKit来生成我的观点。
我现在正在迁移到“flux”架构,用于更改应用状态和触发视图更新。
我遇到的主要问题是并非所有状态更改都应触发UI更新。我不理解避免这种情况的“通用”机制。
基本上,app状态是表示“视图模型”的“大”“JSON”(解析为本机类型对象)。 JSON包含所有视图声明及其初始值。 (JSON非常复杂)
例如,简化的JSON表示包含“pager”组件和导航“next”按钮的视图层次结构:
{
... views ...
{
"pager" : {
"id" : "pager-id-xxx",
"currentPage" : 0,
"pages" : [
....pages....
{},
{},
....pages....
]
},
...
"navigation-next-button" : {
"id" : "navigation-next-button-id-xxxx",
"target" : "pager-id-xxx"
}
},
... views ...
}
我的“Flux”抽象看起来像:
// "Action" portion
@interface ChangePageAction
@property id destinationId; // very simplified action. wraps the destination "id"
@end
@implementation ChangePageReducer
-(JSON)reduce:(JSON)initialJSON action:(ChangePageAction *)changePageAction {
// the "reduce" portion finds the node of the pager (in the JSON) and changes the value by +1
// something like:
// find the node in the JSON with the changePageAction.destinationID
Node *nodeCopy = getNodeCopy(initialJSON,changePageAction.destinationId);
replaceValue(nodeCopy,nodeCopy.currentPage + 1);
// according to FLUX doctrine we are supposed to return a new object
return jsonCopyByReplacingNode(nodeCopy); // a new JSON with the updated values
}
// the navigation button triggers the new state
@implementation NavigationNextButton {
id _destination; // the target of this action
FluxStore _store; // the application flux store
}
-(void)buttonPressed {
ChangePageAction *changePage = ...
[_store dispatch:changePage];
}
@end
在我的“视图控制器”中,我现在得到一个“更新状态”回调
@implementation ViewController
-(void)newState:(JSON)newJSON {
// here all of the view is re-rendered
[self render:JSON];
//The issue is that I don't need or want to re-render for every action that is performed on the state.
// many states don't evaluate to a UI update
// how should I manage that?
}
@end
答案 0 :(得分:2)
不幸的是,在ComponentKit中没有简单的方法可以做到这一点。 React有shouldComponentUpdate
,但ComponentKit没有等效的。
好消息是ComponentKit应该足够聪明,可以重建所有组件,然后意识到没有任何实际改变,最终没有进行UIKit更改。
坏消息是它会花费相当数量的CPU来做这件事。