I created an app using android studio and Kotlin. there is an error that cause that app crash when I want to change the theme of the app or changing language of the app that both needs to restart the dashboard activity. I do not know how to solve that :
here are the codes :
1- in dashboard.kt :
class DashboardActivity : AppCompatActivity() {
private lateinit var storageReference: StorageReference
private lateinit var databaseReference: DatabaseReference
private lateinit var user: User
private lateinit var uid: String
private var toolbar: Toolbar? = null
private var viewPager: ViewPager? = null
private var tabLayout: TabLayout? = null
private var exploreFragment: ExploreFragment? = null
private var flightsFragment: FlightsFragment? = null
private var travelFragment: TravelFragment? = null
private lateinit var auth: FirebaseAuth
private lateinit var binding: ActivityDashboardBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
auth = FirebaseAuth.getInstance()
uid = auth.currentUser?.uid.toString()
databaseReference = FirebaseDatabase.getInstance().getReference("Users")
if (uid.isNotEmpty()){
getUserData()
}
private fun getUserData() {
val scoresRef = Firebase.database.getReference("Users")
scoresRef.child(uid).addValueEventListener(object : ValueEventListener {
@SuppressLint("SetTextI18n")
override fun onDataChange(snapshot: DataSnapshot) {
user = snapshot.getValue(User::class.java)!!
val name = findViewById<TextView>(R.id.tvFirstNameAndLastName)
val phoneNumber = findViewById<TextView>(R.id.tvPhoneNumber)
name.text = user.name+" "+user.lastName
phoneNumber.text = user.phoneNumber
getUserProfile()
}
override fun onCancelled(error: DatabaseError) {
finish()
}
})
}
by removing these two lines :
name.text = user.name+" "+user.lastName
phoneNumber.text = user.phoneNumber
everything works fine, I used that above two lines for retriving data from firebase and it works fine when I show them in nav header in navigationView, but while changing the app theme/language app crash and in android studio shows this error in logcat :
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at af.azdreams.myconquer.DashboardActivity$getUserData$1.onDataChange(DashboardActivity.kt:293)
the dashboard.xml :
<?xml version="1.0" encoding="utf-8"?>
<androidx.drawerlayout.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawerLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".DashboardActivity">
<androidx.coordinatorlayout.widget.CoordinatorLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.google.android.material.appbar.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<androidx.appcompat.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/Orange"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<ImageButton
android:id="@+id/btnSearchUsers"
android:layout_width="wrap_content"
android:background="#0000"
android:layout_height="wrap_content"
app:srcCompat="@drawable/icon_search"
android:contentDescription="@string/todo" />
</androidx.appcompat.widget.Toolbar>
<com.google.android.material.tabs.TabLayout
app:tabTextAppearance="@style/MineCustomTabText"
android:id="@+id/tabLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</com.google.android.material.appbar.AppBarLayout>
<androidx.viewpager.widget.ViewPager
android:id="@+id/viewPager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>
<com.google.android.material.navigation.NavigationView
android:id="@+id/navView"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
app:headerLayout="@layout/header"
app:itemTextAppearance="@style/menu"
app:menu="@menu/nav_menu" />
</androidx.drawerlayout.widget.DrawerLayout>
and the heaader.xml :
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
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"
android:layout_width="match_parent"
android:layout_height="150dp"
android:id="@+id/header"
android:background="@color/Orange">
<de.hdodenhof.circleimageview.CircleImageView
android:id="@+id/circleImageView"
android:layout_width="67dp"
android:layout_height="67dp"
android:layout_marginStart="5dp"
app:civ_border_width="1dp"
android:src="@drawable/profile"
app:civ_border_color="@color/White"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.047"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.213" />
<TextView
android:id="@+id/tvFirstNameAndLastName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="6dp"
android:layout_marginTop="13dp"
android:text=""
android:textColor="@color/White"
android:textSize="15dp"
android:textStyle="bold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.05"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/circleImageView" />
<TextView
android:id="@+id/tvPhoneNumber"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="6dp"
android:text=""
android:textColor="@color/Black"
android:textSize="13dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.05"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/tvFirstNameAndLastName"
app:layout_constraintVertical_bias="0.0" />
</androidx.constraintlayout.widget.ConstraintLayout>
people had same problem when I googled this error, I tried thier ways but app also crashed:(
if you know the right solution for this, please help me.
thanks to who is helping me.
