为 recyclerview 加载画廊适配器时崩溃

Question

编辑：在 JonR85 的回答之后，它返回了图像适配器，但现在在返回膨胀的视图后，它使应用程序崩溃

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
    }

我一直在尝试在一个片段中设置一个 recyclerview（它首先被膨胀然后分配对象（recycler 视图和文本视图）在包含 recyclerview 的图像的类中并请求许可，但不知何故只是当它加载它关闭应用程序的recyclerview（显然在 E/AndroidRuntime: 致命异常: main 进程：com.example.applicationtest，PID：14303 java.lang.NullPointerException 在 com.example.applicationtest.gallery_fragment.loadImages(gallery_fragment.kt:140) 在 com.example.applicationtest.gallery_fragment.onCreateView(gallery_fragment.kt:104) 在 androidx.fragment.app.Fragment.performCreateView(Fragment.java:2963) 在 androidx.fragment.app.FragmentStateManager.createView(FragmentStateManager.java:518) 在 androidx.fragment.app.FragmentStateManager.moveToExpectedState(FragmentStateManager.java:282) 在 androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:2189) 在 androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:2106) 在 androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:2002) 在 androidx.fragment.app.FragmentManager$5.run(FragmentManager.java:524) 在 android.os.Handler.handleCallback(Handler.java:938) 在 android.os.Handler.dispatchMessage(Handler.java:99) 在 android.os.Looper.loop(Looper.java:236) 在 android.app.ActivityThread.main(ActivityThread.java:8037) 在 java.lang.reflect.Method.invoke（本机方法） 在 com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:656) 在 com.android.internal.os.ZygoteInit.main(ZygoteInit.java:967)

调用 GalleryAdapter 的构造函数

我在片段的不同视图中创建了一个 galleryElement（我没有包含它），可能导致崩溃的原因是什么？

    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>

我是如何获得图片列表的

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
        }

Answer 1

class ViewHolder(itemView: View): RecyclerView.ViewHolder(itemView){

        var image : ImageView = view.findViewById(R.id.imageElement1)

        interface IPhotoInterface {

            fun onPhotoClick(stringPath:String): Unit
        }

    }