这是我的代码
struct FirstPage: View {
var body: some View {
VStack{
NavigationView {
VStack{
Text("First Page")
.bold()
NavigationLink(destination: SecondPage()) {
Image(systemName:"arrowshape.turn.up.right.circle")
}
}
}
if (isVisible()) {
Image(systemName:"rhombus.fill")
.frame(width: 100, height: 100, alignment: .center)
}
}
}
}
func isVisible() -> Bool {
let result = Bool.random()
print("result", result)
return result
}
我想做的是调用全局函数isVisible()从SecondPage和改变图像的可见性(systemName:"菱形。填充")。这可能吗?
SecondPage如下:
struct SecondPage: View {
var body: some View {
VStack{
NavigationView {
VStack {
Text("Second Page")
.bold()
Button(action: {
}){
Text("Click here")
}
}
}
}
}
}
我想调用isVisible(),当我点击SecondPage的按钮时改变图像的可见性。
有人知道怎么做吗?
您不需要调用该函数(使用全局函数不是一个好主意)。只用@State
和@Binding
这样的
struct FirstPage: View {
@State private var isVisible: Bool = false
var body: some View {
VStack{
NavigationView {
VStack{
Text("First Page")
.bold()
NavigationLink(destination: SecondPage(isVisible: $isVisible)) {
Image(systemName:"arrowshape.turn.up.right.circle")
}
}
}
if isVisible {
Image(systemName:"rhombus.fill")
.frame(width: 100, height: 100, alignment: .center)
}
}
}
}
struct SecondPage: View {
@Binding var isVisible: Bool
var body: some View {
VStack{
NavigationView {
VStack {
Text("Second Page")
.bold()
Button(action: {
isVisible = Bool.random()
}){
Text("Click here")
}
}
}
}
}
}
如果你仍然需要使用全局函数,那么你需要创建一个静态的共享Observable类。
下面是一个例子:
静态共享类class GlobalClass: ObservableObject {
static var shared = GlobalClass()
@Published var isVisibleVar: Bool = false
func isVisible() {
let result = Bool.random()
print("result", result)
isVisibleVar = result
}
}
观点
struct SecondPage: View {
var body: some View {
VStack{
NavigationView {
VStack {
Text("Second Page")
.bold()
Button(action: {
GlobalClass.shared.isVisible()
/**
Or you can use
GlobalClass.shared.isVisibleVar = Bool.random()
*/
}){
Text("Click here")
}
}
}
}
}
}
struct FirstPage: View {
@ObservedObject private var globalClass = GlobalClass.shared
var body: some View {
VStack{
NavigationView {
VStack{
Text("First Page")
.bold()
NavigationLink(destination: SecondPage()) {
Image(systemName:"arrowshape.turn.up.right.circle")
}
}
}
if globalClass.isVisibleVar {
Image(systemName:"rhombus.fill")
.frame(width: 100, height: 100, alignment: .center)
}
}
}
}