Edit: After JonR85's answer it returned the image adapter but now after returning the inflated view it crashes the application
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
var _galleryFragment:View?
_galleryFragment = requireActivity().findViewById<View>(R.id.gallery_fragment) as View
galleryFragment = GetGalleryFragment(inflater,container) as View
galleryNumberText = (galleryFragment).findViewById(R.id.galleryNumber) as? TextView?
recyclerView = (galleryFragment).findViewById(R.id.recyclerViewImageItems) as? RecyclerView?
if(ContextCompat.checkSelfPermission(this.context as Context,Manifest.permission.READ_EXTERNAL_STORAGE)!=PackageManager.PERMISSION_GRANTED)
{
ActivityCompat.requestPermissions(this.parentFragment?.getActivity() as MainActivity,
Array<String>(2){Manifest.permission.READ_EXTERNAL_STORAGE},READ_PERMISSION_CODE)
var i:Any?;
}
else
{
loadImages()
}
return galleryFragment
}
I have been trying to setup a recyclerview in a fragment(which first is inflated then assigns the objects(recycler view and the text view) in the class that constains the image with the recyclerview and ask for permision but somehow just when it loads the recyclerview it closes the application(apparently crashes at E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.applicationtest, PID: 14303 java.lang.NullPointerException at com.example.applicationtest.gallery_fragment.loadImages(gallery_fragment.kt:140) at com.example.applicationtest.gallery_fragment.onCreateView(gallery_fragment.kt:104) at androidx.fragment.app.Fragment.performCreateView(Fragment.java:2963) at androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:518) at androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:282) at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:2189) at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:2106) at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:2002) at androidx.fragment.app.FragmentManager$5.run(FragmentManager.java:524) at android.os.Handler.handleCallback(Handler.java:938) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:236) at android.app.ActivityThread.main(ActivityThread.java:8037) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:656) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:967)
which calls a GalleryAdapter's constructor
abd I have created a galleryElement in a different view to the fragment(I didnt include it), what could be causing the crash?
fun loadImages(){
recyclerView!!.setHasFixedSize(true)
recyclerView!!.layoutManager = GridLayoutManager(this.activity,4)
try {
this.imageList = ImageGallery.GetImagesList(this.context as Context )
}
catch (ex:Exception)
{
println(ex.message)
}
galleryAdapter = GalleryAdapter(this.context as Context,imageList,
object : IPhotoInterface {
override fun onPhotoClick(stringPath: String):Unit {
//process picture on click
}
})
try {
recyclerView?.adapter = galleryAdapter
galleryNumberText?.text = "${imageList.size} images"
}
catch(ex:Exception)
{
println(ex.message)
}
}```
GalleryAdapter
class GalleryAdapter(var ctx: Context, var listOfImages:MutableList<String>,var photoListener: ViewHolder.IPhotoInterface): RecyclerView.Adapter<GalleryAdapter.ViewHolder>() {
class ViewHolder(itemView: View): RecyclerView.ViewHolder(itemView){
fun GetImageInit(view:View):ImageView =view.findViewById(R.id.imageElement1)
var image : ImageView
init {
image = GetImageInit(itemView) as ImageView
}
interface IPhotoInterface {
fun onPhotoClick(stringPath:String): Unit
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
var inflatedView:View = LayoutInflater.from(this.ctx).inflate(R.layout.gallery_fragment,parent,false)
return ViewHolder(inflatedView)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
var image:String = (listOfImages as List<String>).get(position)
Glide.with(ctx).load(image).into(holder.image)
holder.itemView.setOnClickListener{view->
this.photoListener.onPhotoClick(image)
}
}
override fun getItemCount(): Int {
return this.listOfImages.size
}
}
```
gallery_fragment
```xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".gallery_fragment"
android:background="#333333"
android:orientation="vertical">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="56dp"
android:id="@ id/galleryNumberContainer">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@ id/galleryNumber"
android:layout_centerVertical="true"
android:layout_marginLeft="16dp"
android:textColor="@color/white"
android:textStyle="bold"
android:textSize="18dp"
/>
</RelativeLayout>
<androidx.recyclerview.widget.RecyclerView
android:id="@ id/recyclerViewImageItems"
android:layout_width="match_parent"
android:layout_height="wrap_content">
</androidx.recyclerview.widget.RecyclerView>
</RelativeLayout>
GalleryItem in a different view file
```xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@ id/gallery_item"
>
<ImageView
android:layout_width="match_parent"
android:layout_height="0dp"
android:scaleType="centerCrop"
app:layout_constraintDimensionRatio="1"
android:id="@ id/imageElement1"
tools:ignore="MissingConstraints"
></ImageView>
</androidx.constraintlayout.widget.ConstraintLayout>
how I have obtained the image list
kotlin
public fun GetImagesList(context: Context):MutableList<string>{
lateinit var uri:Uri
var cursor:Cursor?
var columnIndexDataId:Int =0
var imageCollectionList:MutableList<string> = mutableListOf<string>()
var projection:Array<string>
var absoluteImagePath:String =""
uri =MediaStore.Images.Media.EXTERNAL_CONTENT_URI
var selection:string = "_id?"
// var selectionArgs :Array<string> = arrayOf(DocumentsContract.getDocumentId(uri).split(":")[1])
try {
val columnName:string="_data"
projection = arrayOf(columnName)
cursor =context.contentResolver.query(uri,null,null,null,null)
//if cursor is not null then execute codeblock
cursor?.let {
while(it.moveToNext())
{
val columnIndex = cursor.getColumnIndexOrThrow(columnName)
absoluteImagePath =cursor.getString(columnIndex)
imageCollectionList.add(absoluteImagePath)
}
}
}
catch (ex:Exception){
print(ex.message)
}
return imageCollectionList
}
CodePudding user response：
class ViewHolder(itemView: View): RecyclerView.ViewHolder(itemView){
var image : ImageView = view.findViewById(R.id.imageElement1)
interface IPhotoInterface {
fun onPhotoClick(stringPath:String): Unit
}
}