...

app/src/main/java/com/base/pdfviewerscannerwhite/ui/document/pdf/PdfMergeActivity.kt

 package com.base.pdfviewerscannerwhite.ui.document.pdf
 
+import androidx.activity.addCallback
 import androidx.recyclerview.widget.ItemTouchHelper
 import com.base.pdfviewerscannerwhite.bean.DocumentBean
 import com.base.pdfviewerscannerwhite.databinding.ActivityPdfMergeBinding
 import com.base.pdfviewerscannerwhite.helper.BaseActivity
+import com.base.pdfviewerscannerwhite.utils.LogEx
 
 class PdfMergeActivity : BaseActivity<ActivityPdfMergeBinding>() {
 
+    private val TAG = "PdfMergeActivity"
     override val binding: ActivityPdfMergeBinding by lazy {
         ActivityPdfMergeBinding.inflate(layoutInflater)
     }
@@ -17,14 +20,38 @@ class PdfMergeActivity : BaseActivity<ActivityPdfMergeBinding>() {
         initAdapter()
     }
 
+    override fun initListener() {
+        super.initListener()
+        onBackPressedDispatcher.addCallback {
+            finish()
+        }
+        binding.flFanhui.setOnClickListener {
+            onBackPressedDispatcher.onBackPressed()
+        }
+    }
+
     private fun initAdapter() {
         val callBack = PdfMergeItemTouchHelperCallBack()
         val itemTouchHelper = ItemTouchHelper(callBack)
         itemTouchHelper.attachToRecyclerView(binding.rv)
+        adapter = PdfMergeAdapter(itemTouchHelper,callBack)
+        binding.rv.adapter = adapter
 
+        callBack.changeListOrder = { olderPosition, newPosition ->
+            val bean = mergePdfList[olderPosition]
+            mergePdfList.remove(bean)
+            mergePdfList.add(newPosition, bean)
 
-        adapter = PdfMergeAdapter(callBack)
-        binding.rv.adapter = adapter
+            mergePdfList.forEach {
+                LogEx.logDebug(TAG, "mergePdfList ${it.path}")
+            }
+
+            adapter.items.forEach {
+                LogEx.logDebug(TAG, "items ${it.path}")
+            }
+
+//            adapter.items = mergePdfList
+        }
 
         mergePdfList.let { adapter.submitList(it) }
     }

app/src/main/java/com/base/pdfviewerscannerwhite/ui/document/pdf/PdfMergeAdapter.kt

@@ -2,23 +2,24 @@ package com.base.pdfviewerscannerwhite.ui.document.pdf
 
 import android.annotation.SuppressLint
 import android.content.Context
-import android.view.GestureDetector
-import android.view.GestureDetector.SimpleOnGestureListener
 import android.view.MotionEvent
 import android.view.View
 import android.view.ViewGroup
+import androidx.recyclerview.widget.ItemTouchHelper
 import androidx.recyclerview.widget.RecyclerView
 import com.base.pdfviewerscannerwhite.R
 import com.base.pdfviewerscannerwhite.bean.DocumentBean
 import com.base.pdfviewerscannerwhite.databinding.ItemPdfMergeBinding
 import com.base.pdfviewerscannerwhite.utils.KotlinExt.toFormatSize
 import com.base.pdfviewerscannerwhite.utils.KotlinExt.toFormatTime4
+import com.base.pdfviewerscannerwhite.utils.LogEx
 import com.base.pdfviewerscannerwhite.utils.XmlEx.inflate
 import com.chad.library.adapter4.BaseQuickAdapter
 import java.io.File
 
 
 class PdfMergeAdapter(
+    val itemTouchHelper: ItemTouchHelper,
     val callBack: PdfMergeItemTouchHelperCallBack
 ) : BaseQuickAdapter<DocumentBean, PdfMergeAdapter.PdfMergeViewHolder>() {
 
@@ -35,15 +36,23 @@ class PdfMergeAdapter(
         binding.tvName.text = file.name
         binding.tvInfo.text = file.lastModified().toFormatTime4() + " " + file.length().toFormatSize()
 
-
-        binding.ivMove.setOnLongClickListener {
+        binding.ivMove.setOnTouchListener(object : View.OnTouchListener {
+            override fun onTouch(v: View?, event: MotionEvent?): Boolean {
+                if (event?.action == MotionEvent.ACTION_DOWN) {
                     callBack.enableLongPress = true
-            true
+                    LogEx.logDebug(TAG, "ACTION_DOWN ${System.currentTimeMillis()}")
+                    // 长按时启动拖动
+                    itemTouchHelper.startDrag(holder)
+                    return true
                 }
-
+                return false
+            }
+        })
     }
 
     override fun onCreateViewHolder(context: Context, parent: ViewGroup, viewType: Int): PdfMergeViewHolder {
         return PdfMergeViewHolder(R.layout.item_pdf_merge.inflate(parent))
     }
+
+
 }
\ No newline at end of file

app/src/main/java/com/base/pdfviewerscannerwhite/ui/document/pdf/PdfMergeItemTouchHelperCallBack.kt

@@ -6,17 +6,22 @@ import com.base.pdfviewerscannerwhite.utils.LogEx
 
 class PdfMergeItemTouchHelperCallBack : ItemTouchHelper.Callback() {
 
+    var changeListOrder: ((olderPosition: Int, newPosition: Int) -> Unit)? = null
+
     var enableLongPress: Boolean = false
 
     private val TAG = "PdfMergeItemTouchHelperCallBack"
     override fun getMovementFlags(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder): Int {
 
         //支持上下左右拖动
-        //ACTION_STATE_IDLE item默认滑动方向
+//        ACTION_STATE_IDLE item默认滑动方向
         return makeMovementFlags(
             ItemTouchHelper.UP or ItemTouchHelper.DOWN or ItemTouchHelper.START or ItemTouchHelper.END,
             ItemTouchHelper.ACTION_STATE_IDLE
         )
+        // 禁用默认的拖动和滑动
+//        return makeMovementFlags(0, 0);
+
     }
 
     /**
@@ -29,6 +34,8 @@ class PdfMergeItemTouchHelperCallBack : ItemTouchHelper.Callback() {
             viewHolder.adapterPosition,
             target.adapterPosition
         )
+
+        changeListOrder?.invoke(viewHolder.layoutPosition, target.layoutPosition)
         enableLongPress = false
         return true
     }
@@ -37,8 +44,19 @@ class PdfMergeItemTouchHelperCallBack : ItemTouchHelper.Callback() {
 
 
     override fun isLongPressDragEnabled(): Boolean {
-        LogEx.logDebug(TAG, "isLongPressDragEnabled $enableLongPress")
+        LogEx.logDebug(TAG, "isLongPressDragEnabled $enableLongPress ${System.currentTimeMillis()}")
         return enableLongPress
     }
 
+    override fun onSelectedChanged(viewHolder: RecyclerView.ViewHolder?, actionState: Int) {
+        super.onSelectedChanged(viewHolder, actionState)
+        if (actionState == ItemTouchHelper.ACTION_STATE_IDLE) {
+            // 当没有动作时，取消拖动状态
+            viewHolder?.itemView?.setPressed(false)
+        } else if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
+            // 当滑动时，设置拖动状态
+            viewHolder?.itemView?.setPressed(true)
+        }
+    }
+
 }
\ No newline at end of file

app/src/main/res/layout/item_pdf_merge.xml

@@ -55,6 +55,7 @@
 
 
     <LinearLayout
+        android:id="@+id/ll"
         android:layout_width="0dp"
         android:layout_height="wrap_content"
         android:layout_marginStart="15dp"