问题描述
我在View生命周期和快速的视图可重用性方面苦苦挣扎。
在此示例中,可以使用其他ID重新初始化我的视图,然后必须负责异步显示用户名。我以前在OnAppear内部运行loadData函数,但是在第一次加载后它不会重新初始化。但是,既然我添加了init函数,则在任何init上都不会完全更新我的状态和视图。
struct TestView: View {
@State var userName : String = ""
init(id: Int){
print("Init \(id)")
loadData(id: id)
}
var body: some View {
vstack{
if userName != "" {
Text(userName)
}
}
}
// function that will return username at some point in the future
private func loadData(id: Int){
let Obs: Observable<String> = manager.getUser(id: id)
Obs.subscribe(onNext: { user in
self.userName = user.userName
})
}
}
解决方法
视图无法重建,因为在提供的变体中它被解释为相等的(因为没有存储任何不同的属性)
尝试以下
struct TestView: View {
let id: Int // << changing this should make view rebuild
@State private var userName : String = ""
var body: some View {
VStack{
if userName != "" {
Text(userName)
}
}
.onAppear {
print("Rebuild with: \(id)")
loadData(id: id)
}
.id(self.id) // << Update: this one !!
}
// function that will return username at some point in the future
private func loadData(id: Int){
let Obs: Observable<String> = manager.getUser(id: id)
Obs.subscribe(onNext: { user in
self.userName = user.userName
})
}
}