当我尝试从 DialogFragment 访问布局中的元素时，出现 NullPointerException。我已经检查过了，如果我在同一个 DialogFragment 中调用 getView()，结果为“null”。
先感谢您！
这是调用提交 FragmentDialog "NewPOIDialog" 的 Activity
class MainActivity : AppCompatActivity() {
//Variables for Location service
private var hasGps: Boolean = false
private var hasNetwork: Boolean = false
private var locationGps: Location? = null
private var locationNetwork: Location? = null
private companion object {
private const val TAG = "MainActivity"
}
private lateinit var auth: FirebaseAuth
private lateinit var permissionsRequestor: PermissionsRequestor
private lateinit var mapView: MapView
private lateinit var mapActivity: MapActivity
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO)
//Get the authorisation from Firebase
auth = Firebase.auth
Log.d("", "HERE SDK version: " + SDKBuildInformation.sdkVersion().versionName)
// Get a MapView instance from layout.
mapView = findViewById(R.id.map_view)
mapView.onCreate(savedInstanceState)
location()
handleAndroidPermissions()
}
fun searchInMap(view: View?) {
NewPOIDialog().show(supportFragmentManager, "test")
}
fun clearRouteButtonClicked(view: View?) {
mapActivity.clearMap()
}
fun clearWaypoints(view: View?) {
mapActivity.clearWaypoints()
}
override fun onCreateOptionsMenu(menu: Menu?): Boolean {
menuInflater.inflate(R.menu.menu_main, menu)
return true //we provided the menu that needs to be inflated
}
override fun onOptionsItemSelected(item: MenuItem): Boolean {
if (item.itemId == R.id.miLogout) {
Log.i(TAG, "Logout")
//Logout the user
auth.signOut()
LoginManager.getInstance().logOut()
val logoutIntent = Intent(this, LoginActivity::class.java)
logoutIntent.flags =
Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK //Clear the backstack
startActivity(logoutIntent)
}
return super.onOptionsItemSelected(item)
}
private fun handleAndroidPermissions() {
permissionsRequestor = PermissionsRequestor(this)
permissionsRequestor.request(object : PermissionsRequestor.ResultListener {
override fun permissionsGranted() {
loadMapScene()
}
override fun permissionsDenied() {
Log.e(TAG, "Permissions denied by user.")
}
})
}
override fun onRequestPermissionsResult(
requestCode: Int,
permissions: Array<out String>,
grantResults: IntArray
) {
permissionsRequestor.onRequestPermissionsResult(requestCode, grantResults)
}
private fun loadMapScene() {
mapView.mapScene.loadScene(MapScheme.NORMAL_DAY, object : MapScene.LoadSceneCallback {
override fun onLoadScene(p0: MapError?) {
if (p0 == null) {
mapActivity = MapActivity(this@MainActivity, mapView, supportFragmentManager)
mapView.camera.lookAt(
GeoCoordinates(53.57407651646072, -1.525012498490556),
100000.0
)
} else {
Log.d("TAG", "onLoadScene failed: $p0")
}
}
})
}
fun location() {
var locationManager: LocationManager = getSystemService(LOCATION_SERVICE) as LocationManager
hasGps = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)
hasNetwork = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)
if (hasGps || hasNetwork) {
if (hasGps) {
Log.d(TAG, "hasGPS")
if (ActivityCompat.checkSelfPermission(
this,
Manifest.permission.ACCESS_FINE_LOCATION
) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(
this,
Manifest.permission.ACCESS_COARSE_LOCATION
) != PackageManager.PERMISSION_GRANTED
) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
//return
handleAndroidPermissions()
}
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
1000,
0f,
object :
LocationListener {
override fun onLocationChanged(p0: Location?) {
if (p0 != null) {
locationNetwork = p0
}
}
override fun onStatusChanged(p0: String?, p1: Int, p2: Bundle?) {
}
override fun onProviderEnabled(p0: String?) {
}
override fun onProviderDisabled(p0: String?) {
}
})
val localGpsLocation =
locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER)
if (localGpsLocation != null) {
locationGps = localGpsLocation
}
}
///////////////////////////////////////////////////////////////////////////
if (hasNetwork) {
Log.d(TAG, "hasGPS")
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
1000,
0f,
object :
LocationListener {
override fun onLocationChanged(p0: Location?) {
if (p0 != null) {
locationNetwork = p0
}
}
override fun onStatusChanged(p0: String?, p1: Int, p2: Bundle?) {
}
override fun onProviderEnabled(p0: String?) {
}
override fun onProviderDisabled(p0: String?) {
}
})
val localGpsLocation =
locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER)
if (localGpsLocation != null) {
locationGps = localGpsLocation
}
val localNetworkLocation =
locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER)
if (localNetworkLocation != null) {
locationNetwork = localNetworkLocation
}
if (locationGps != null && locationNetwork != null) {
if (locationGps!!.accuracy!! > locationNetwork!!.accuracy!!) { //The lower number is the accurate location
Log.d(TAG, "Network Latitude : ${locationNetwork!!.latitude}")
Log.d(TAG, "Network Longitude : ${locationNetwork!!.longitude}")
latitude_txt.text = "Latitude : ${locationNetwork!!.latitude} - Network"
longitude_txt.text = "Longitude : ${locationNetwork!!.longitude} - Network"
latitude_txt.text = "Latitude : ${locationGps!!.latitude} - Gps"
longitude_txt.text = "Longitude : ${locationGps!!.longitude} - Gps"
} else {
Log.d(TAG, "Gps Latitude : ${locationGps!!.latitude}")
Log.d(TAG, "Gps Longitude : ${locationGps!!.longitude}")
latitude_txt.text = "Latitude : ${locationGps!!.latitude} - Gps"
longitude_txt.text = "Longitude : ${locationGps!!.longitude} - Gps"
}
}
}
// if (locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER) &&
// this.getPackageManager().hasSystemFeature(PackageManager.FEATURE_LOCATION_GPS)
// ) {
// locationManager.requestLocationUpdates(
// LocationManager.GPS_PROVIDER,
// LOCATION_UPDATE_INTERVAL_IN_MS,
// 1,
// this
// );
// } else if (locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)) {
// locationManager.requestLocationUpdates(
// LocationManager.NETWORK_PROVIDER,
// LOCATION_UPDATE_INTERVAL_IN_MS,
// 1,
// this
// );
// } else {
// Log.d(TAG, "Positioning not possible.");
// // ...
// }
}
}
}
新POI对话框
该视图最初调用如下，我在收到 StackOverFlowError 时更改了它： var view = layoutInflater.inflate(R.layout.activity_new_poi_dialog,null)
class NewPOIDialog : DialogFragment() {
override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
var view = LayoutInflater.from(context).inflate(R.layout.activity_new_poi_dialog, null)
var dialog = AlertDialog.Builder(requireContext())
.setMessage("TITLE")
.setView(view)
.setPositiveButton("ok") { _, _ -> }
.setNegativeButton("Cancel") { _, _ -> }
.create()
//THIS LINE WORKS FINE
var coordinatesvalue = view.findViewById<TextView>(R.id.coordinates_value)
coordinatesvalue.text =
"${arguments?.getDouble("latitude")}\n, ${arguments?.getDouble("longitude")}"
//THIS CAUSES A NULL POINTER EXCEPTION
coordinates_value.text = "TEST"
return dialog
}
}
我得到的例外：
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.robin.socialparking, PID: 19187
java.lang.NullPointerException: coordinates_value must not be null
at com.robin.socialparking.dialog.NewPOIDialog.onCreateDialog(NewPOIDialog.kt:54)
at androidx.fragment.app.DialogFragment.onGetLayoutInflater(DialogFragment.java:380)
at androidx.fragment.app.Fragment.performGetLayoutInflater(Fragment.java:1412)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:881)
at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManagerImpl.java:1238)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:1303)
at androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:439)
at androidx.fragment.app.FragmentManagerImpl.executeOps(FragmentManagerImpl.java:2079)
at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManagerImpl.java:1869)
at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManagerImpl.java:1824)
at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManagerImpl.java:1727)
at androidx.fragment.app.FragmentManagerImpl$2.run(FragmentManagerImpl.java:150)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7050)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)
I/Process: Sending signal. PID: 19187 SIG: 9