如何在开始目的地隐藏工具栏

Question

我试图在开始片段中隐藏工具栏，但是当我在navigationUI中显式设置工具栏时，View.GONE不起作用。

// mainActivity
class MainActivity : AppCompatActivity() {
private lateinit var binding: ActivityMainBinding
private lateinit var navController: NavController
private lateinit var appBarConfiguration: AppBarConfiguration
private lateinit var drawerLayout: DrawerLayout
private lateinit var toolbar: androidx.appcompat.widget.Toolbar
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = DataBindingUtil.setContentView(this, R.layout.activity_main)
drawerLayout = binding.drawerLayout
navController = this.findNavController(R.id.myNavHostFragment)
toolbar = binding.toolbar
// setSupportActionBar(toolbar)
appBarConfiguration = AppBarConfiguration(
setOf(R.id.secondFragment, R.id.thirdFragment), drawerLayout
)
navController.addOnDestinationChangedListener { _, destination, _ ->
when (destination.id) {
R.id.startFragment -> {
toolbar.visibility = View.GONE
}
}
}
NavigationUI.setupActionBarWithNavController(
this, navController, appBarConfiguration
)
NavigationUI.setupWithNavController(binding.navView, navController)
}
override fun onSupportNavigateUp(): Boolean {
return NavigationUI.navigateUp(navController, appBarConfiguration)
}
}
// activity_main.xml
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools">
<androidx.drawerlayout.widget.DrawerLayout
android:id="@+id/drawerLayout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<androidx.appcompat.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<fragment
android:id="@+id/myNavHostFragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:defaultNavHost="true"
app:navGraph="@navigation/navigation" />
</androidx.constraintlayout.widget.ConstraintLayout>
<com.google.android.material.navigation.NavigationView
android:id="@+id/navView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="start"
app:menu="@menu/drawer_menu"
app:headerLayout="@layout/drawer_header"/>
</androidx.drawerlayout.widget.DrawerLayout>
</layout>

Answer 1

像这样尝试

toolbar = binding.toolbar
setSupportActionBar(toolbar) // uncomment this line
// ....
navController.addOnDestinationChangedListener { _, destination, _ ->
when (destination.id) {
R.id.startFragment -> {
supportActionBar?.hide() // to hide
}else{
supportActionBar?.show() // to show
}
}
}

或

您可以像下面这样在fragment中隐藏toolbar。

override fun onResume() {
super.onResume()
(activity as AppCompatActivity?)!!.supportActionBar!!.hide()
}

并且不要忘记在同一fragment' to show the工具栏中调用onStop()内的show()to other片段or活动"。

override fun onStop() {
super.onStop()
(activity as AppCompatActivity?)!!.supportActionBar!!.show()
}

Answer 2

我在activity_main.xml中添加了自己的工具栏，并将主题的默认样式替换为NoActionBar。

// in activity_main.xml
<androidx.appcompat.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
android:elevation="4dp"
android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
app:layout_constraintTop_toTopOf="parent"
app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />
// in style.xml
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
...
</style>