Recently, more and more people are using SwiftUI to develop iOS apps, but as a new tool SwiftUI still has a lot of unresolved problems.
Lots of developers find they cannot hide TabBar when they use NavigationView to navigate to a new view in SwiftUI. It is pretty annoying.
Here, I would like to give you guys a solution to solve this problem. I will explain some View Hierarchy knowledge first to help you guys understand what's actually going on in swiftUI when we try to use NavigationView and TabView. You can also directly jump to solution if you want to.
Here is a demo app. In this demo, I have two tabs, tab1 and tab2, in a TabView, and I want to tap the text in each tab to navigate to NavigatedView. So, I add NavigationView and NavigationLink to the contents in each tab. The code is as below.
import SwiftUI
struct ContentView: View {
@State var tabSelection: Tabs = .tab1
var body: some View {
TabView(selection: $tabSelection){
NavigationView{ //if you write the NavigationView here, you cannot remove TabBar after navigation
NavigationLink(destination: NavigatedView()){
VStack{
Text("Here is Tab 1")
Text("Tap me to NavigatedView")
}
.navigationBarTitle("Tab1")
}
}
.tabItem { Text("Tab 1") }
.tag(Tabs.tab1)
NavigationView{//Tab2 also has a NavigationView
NavigationLink(destination: NavigatedView()){
VStack{
Text("Here is Tab 2")
Text("Tap me to NavigatedView")
}
.navigationBarTitle("Tab2")
}
}
.tabItem { Text("Tab 2") }
.tag(Tabs.tab2)
}
}
enum Tabs{
case tab1, tab2
}
}import SwiftUI
struct NavigatedView: View {
var body: some View {
Text("Hi! This is the NavigatedView")
.navigationBarTitle("NavigatedView")
}
}When running the code, there is a problem, you can see when I tap the text in Tab1 and go to the NavigatedView, TabBar is still at the bottom. However, when we develop an app, sometimes we really want the TabBar to disappear when navigating.
| Navigation in TabView | before navigation | after navigation |
|---|---|---|
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Why does it run like this? To understand this, let's take a look at View Hierarchy in SwistUI. When you write the NavigationView in TabView, the things goes in SwiftUI like the following pictures.TabView contains NavigationView, and it makes everything happening in NavigationView cannot affect TabView, because NavigationView is just a child-view of TabView. So, when navigating to another view, NavigationView changes, but as the super-view TabView will stay what it is.
when the Tap Here to a new view button is tapped, only the red part (NavigationView) changes to orange part (NavigatedView), but the blue part ( TabView) stays the same. |
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Here, it should be clear. If we want to hide the TabBar, we just write TabView into NavigationView, making the NavigationView the super-view and the TabView the child-view, which is just opposite to the above View Hierarchy.
when the Tap Here to a new view button is tapped, the blue part (NavigationView) changes to orange part (NavigatedView), so the TabBar in red part disappears itself. |
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After knowing this, we just need to modify our code a little to let NavigationView contain TabViewand then we can perfectly solve the problem.
Like what has been mentioned above, we just rewrite our code to make NavigationView contain TabView.
import SwiftUI
struct ContentView: View {
@State var tabSelection: Tabs = .tab1
var body: some View {
NavigationView{
TabView(selection: $tabSelection){
// NavigationView{ //if you write the NavigationView here, you cannot remove TabBar after navigation
NavigationLink(destination: NavigatedView()){
VStack{
Text("Here is Tab 1")
Text("Tap me to NavigatedView")
}
.navigationBarTitle("Tab1")//NavigationBarTitle does not work here
}
// }
.tabItem { Text("Tab 1") }
.tag(Tabs.tab1)
// NavigationView{//Tab2 also has a NavigationView
NavigationLink(destination: NavigatedView()){
VStack{
Text("Here is Tab 2")
Text("Tap me to NavigatedView")
}
.navigationBarTitle("Tab2")//NavigationBarTitle does not work here
}
// }
.tabItem { Text("Tab 2") }
.tag(Tabs.tab2)
}
}
}
enum Tabs{
case tab1, tab2
}
}Another problem here is our NavigationBarTitle does not display itself when we write it in TabView.
| Navigation in TabView | before navigation | after navigation |
|---|---|---|
 |
 |
 |
The solution is also easy. Just move the NavigationBarTitle to the end of TabView and it works fine. But in this way, when we tap different tabs, the NavigationBarTitle is always the same, which is not what we want. So, I also added a function returnNaviBarTitle to display the right NavigationBarTitle based on the selected tab. The following code is the final version.
import SwiftUI
struct ContentView: View {
@State var tabSelection: Tabs = .tab1
var body: some View {
NavigationView{
TabView(selection: $tabSelection){
// NavigationView{ //if you write the NavigationView here, you cannot remove TabBar after navigation
NavigationLink(destination: NavigatedView()){
VStack{
Text("Here is Tab 1")
Text("Tap me to NavigatedView")
}
// .navigationBarTitle("Tab1")//NavigationBarTitle does not work here
}
// }
.tabItem { Text("Tab 1") }
.tag(Tabs.tab1)
// NavigationView{//Tab2 also has a NavigationView
NavigationLink(destination: NavigatedView()){
VStack{
Text("Here is Tab 2")
Text("Tap me to NavigatedView")
}
// .navigationBarTitle("Tab2")//NavigationBarTitle does not work here
}
// }
.tabItem { Text("Tab 2") }
.tag(Tabs.tab2)
}
.navigationBarTitle(returnNaviBarTitle(tabSelection: self.tabSelection))//add the NavigationBarTitle here.
}
}
enum Tabs{
case tab1, tab2
}
func returnNaviBarTitle(tabSelection: Tabs) -> String{//this function will return the correct NavigationBarTitle when different tab is selected.
switch tabSelection{
case .tab1: return "Tab1"
case .tab2: return "Tab2"
}
}
}| Navigation in TabView | before navigation | after navigation |
|---|---|---|
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Here ends the doc! Hope you have learned something. Thanks so much for your reading.