优化代码

app/src/main/java/io/legado/app/ui/widget/recycler/DragSelectTouchHelper.kt

@@ -190,7 +190,8 @@ class DragSelectTouchHelper(
     private var mLastRealEnd = RecyclerView.NO_POSITION
     private var mSlideStateStartPosition = RecyclerView.NO_POSITION
     private var mHaveCalledSelectStart = false
-    private val mScrollRunnable: Runnable = object : Runnable {
+    private val mScrollRunnable: Runnable by lazy {
+        object : Runnable {
             override fun run() {
                 if (mIsScrolling) {
                     scrollBy(mScrollDistance)
@@ -198,7 +199,9 @@ class DragSelectTouchHelper(
                 }
             }
         }
-    private val mOnItemTouchListener: OnItemTouchListener = object : OnItemTouchListener {
+    }
+    private val mOnItemTouchListener: OnItemTouchListener by lazy {
+        object : OnItemTouchListener {
             override fun onInterceptTouchEvent(rv: RecyclerView, e: MotionEvent): Boolean {
                 Logger.d("onInterceptTouchEvent: x:" + e.x + ",y:" + e.y
                         + ", " + MotionEvent.actionToString(e.action))
@@ -292,6 +295,7 @@ class DragSelectTouchHelper(
                 }
             }
         }
+    }
 
     init {
         setHotspotRatio(DEFAULT_HOTSPOT_RATIO)
@@ -316,13 +320,11 @@ class DragSelectTouchHelper(
         if (mRecyclerView === recyclerView) {
             return  // nothing to do
         }
-        if (mRecyclerView != null) {
+        mRecyclerView?.removeOnItemTouchListener(mOnItemTouchListener)
-            mRecyclerView!!.removeOnItemTouchListener(mOnItemTouchListener)
-        }
         mRecyclerView = recyclerView
-        if (mRecyclerView != null) {
+        mRecyclerView?.let {
-            mRecyclerView!!.addOnItemTouchListener(mOnItemTouchListener)
+            it.addOnItemTouchListener(mOnItemTouchListener)
-            mRecyclerView!!.addOnLayoutChangeListener(mOnLayoutChangeListener)
+            it.addOnLayoutChangeListener(mOnLayoutChangeListener)
         }
     }
 
@@ -510,8 +512,8 @@ class DragSelectTouchHelper(
 
     private fun activeSelectInternal(position: Int) {
         // We should initialize the hotspot here, because its data may be delayed load
-        if (mRecyclerView != null) {
+        mRecyclerView?.let {
-            init(mRecyclerView!!.height)
+            init(it.height)
         }
         if (position == RecyclerView.NO_POSITION) {
             Logger.logSelectStateChange(mSelectState, SELECT_STATE_SLIDE)
@@ -553,7 +555,7 @@ class DragSelectTouchHelper(
         updateSelectedRange(rv, e.x, e.y)
     }
 
-    private fun updateSelectedRange(rv: RecyclerView?, x: Float, y: Float) {
+    private fun updateSelectedRange(rv: RecyclerView, x: Float, y: Float) {
         val position = getItemPosition(rv, x, y)
         if (position != RecyclerView.NO_POSITION && mEnd != position) {
             mEnd = position
@@ -685,7 +687,7 @@ class DragSelectTouchHelper(
     private fun stopAutoScroll() {
         if (mIsScrolling) {
             mIsScrolling = false
-            mRecyclerView!!.removeCallbacks(mScrollRunnable)
+            mRecyclerView?.removeCallbacks(mScrollRunnable)
         }
     }
 
@@ -698,7 +700,7 @@ class DragSelectTouchHelper(
             }
         mRecyclerView!!.scrollBy(0, scrollDistance)
         if (mLastX != Float.MIN_VALUE && mLastY != Float.MIN_VALUE) {
-            updateSelectedRange(mRecyclerView, mLastX, mLastY)
+            updateSelectedRange(mRecyclerView!!, mLastX, mLastY)
         }
     }
 
@@ -720,8 +722,8 @@ class DragSelectTouchHelper(
         return getItemPosition(rv, e.x, e.y)
     }
 
-    private fun getItemPosition(rv: RecyclerView?, x: Float, y: Float): Int {
+    private fun getItemPosition(rv: RecyclerView, x: Float, y: Float): Int {
-        val v = rv!!.findChildViewUnder(x, y)
+        val v = rv.findChildViewUnder(x, y)
         if (v == null) {
             val layoutManager = rv.layoutManager
             if (layoutManager is GridLayoutManager) {