feat: 优化代码

app/src/main/java/io/legado/app/ui/book/read/page/delegate/HorizontalPageDelegate.kt

@@ -4,7 +4,6 @@ import android.graphics.Bitmap
 import android.view.MotionEvent
 import io.legado.app.ui.book.read.page.PageView
 import io.legado.app.utils.screenshot
-import kotlin.math.abs
 
 abstract class HorizontalPageDelegate(pageView: PageView) : PageDelegate(pageView) {
 
@@ -52,12 +51,31 @@ abstract class HorizontalPageDelegate(pageView: PageView) : PageDelegate(pageVie
     }
 
     private fun onScroll(event: MotionEvent) {
+
+        val action: Int = event.action
+        val pointerUp =
+            action and MotionEvent.ACTION_MASK == MotionEvent.ACTION_POINTER_UP
+        val skipIndex = if (pointerUp) event.actionIndex else -1
+        // Determine focal point
+        var sumX = 0f
+        var sumY = 0f
+        val count: Int = event.pointerCount
+        for (i in 0 until count) {
+            if (skipIndex == i) continue
+            sumX += event.getX(i)
+            sumY += event.getY(i)
+        }
+        val div = if (pointerUp) count - 1 else count
+        val focusX = sumX / div
+        val focusY = sumY / div
         //判断是否移动了
         if (!isMoved) {
-            isMoved = abs(startX - event.x) > slop
-                    || abs(startX - event.x) > abs(startY - event.y)
+            val deltaX = (focusX - startX).toInt()
+            val deltaY = (focusY - startY).toInt()
+            val distance = deltaX * deltaX + deltaY * deltaY
+            isMoved = distance > slopSquare
             if (isMoved) {
-                if (event.x - startX > 0) {
+                if (sumX - startX > 0) {
                     //如果上一页不存在
                     if (!hasPrev()) {
                         noNext = true
@@ -78,7 +96,7 @@ abstract class HorizontalPageDelegate(pageView: PageView) : PageDelegate(pageVie
             isCancel = if (mDirection == Direction.NEXT) touchX > lastX else touchX < lastX
             isRunning = true
             //设置触摸点
-            setTouchPoint(event.x, event.y)
+            setTouchPoint(sumX, sumY)
         }
     }
 

app/src/main/java/io/legado/app/ui/book/read/page/delegate/PageDelegate.kt

@@ -23,7 +23,7 @@ abstract class PageDelegate(protected val pageView: PageView) :
         pageView.width * 0.66f, pageView.height * 0.66f
     )
     protected val context: Context = pageView.context
-    protected val slop = ViewConfiguration.get(context).scaledTouchSlop
+
     //起始点
     protected var startX: Float = 0f
     protected var startY: Float = 0f
@@ -41,18 +41,23 @@ abstract class PageDelegate(protected val pageView: PageView) :
     protected var viewWidth: Int = pageView.width
     protected var viewHeight: Int = pageView.height
 
-    private val snackBar: Snackbar by lazy {
-        Snackbar.make(pageView, "", Snackbar.LENGTH_SHORT)
-    }
-
     private val scroller: Scroller by lazy {
         Scroller(pageView.context, DecelerateInterpolator())
     }
 
+    protected val slopSquare by lazy {
+        val scaledTouchSlop = ViewConfiguration.get(context).scaledTouchSlop
+        scaledTouchSlop * scaledTouchSlop
+    }
+
     private val detector: GestureDetector by lazy {
         GestureDetector(pageView.context, this)
     }
 
+    private val snackBar: Snackbar by lazy {
+        Snackbar.make(pageView, "", Snackbar.LENGTH_SHORT)
+    }
+
     var isMoved = false
     var noNext = true
 
@@ -189,6 +194,7 @@ abstract class PageDelegate(protected val pageView: PageView) :
     @CallSuper
     open fun onTouch(event: MotionEvent) {
         if (isStarted) return
+        detector.setIsLongpressEnabled(false)
         if (!detector.onTouchEvent(event)) {
             //GestureDetector.onFling小幅移动不会触发,所以要自己判断
             when (event.action) {

app/src/main/java/io/legado/app/ui/book/read/page/delegate/ScrollPageDelegate.kt

@@ -4,7 +4,6 @@ import android.view.MotionEvent
 import android.view.VelocityTracker
 import io.legado.app.ui.book.read.page.ChapterProvider
 import io.legado.app.ui.book.read.page.PageView
-import kotlin.math.abs
 
 class ScrollPageDelegate(pageView: PageView) : PageDelegate(pageView) {
 
@@ -46,9 +45,28 @@ class ScrollPageDelegate(pageView: PageView) : PageDelegate(pageView) {
     private fun onScroll(event: MotionEvent) {
         mVelocity.addMovement(event)
         mVelocity.computeCurrentVelocity(velocityDuration)
-        setTouchPoint(event.x, event.y)
+        val action: Int = event.action
+        val pointerUp =
+            action and MotionEvent.ACTION_MASK == MotionEvent.ACTION_POINTER_UP
+        val skipIndex = if (pointerUp) event.actionIndex else -1
+        // Determine focal point
+        var sumX = 0f
+        var sumY = 0f
+        val count: Int = event.pointerCount
+        for (i in 0 until count) {
+            if (skipIndex == i) continue
+            sumX += event.getX(i)
+            sumY += event.getY(i)
+        }
+        val div = if (pointerUp) count - 1 else count
+        val focusX = sumX / div
+        val focusY = sumY / div
+        setTouchPoint(sumX, sumY)
         if (!isMoved) {
-            isMoved = abs(startX - event.x) > slop || abs(startY - event.y) > slop
+            val deltaX = (focusX - startX).toInt()
+            val deltaY = (focusY - startY).toInt()
+            val distance = deltaX * deltaX + deltaY * deltaY
+            isMoved = distance > slopSquare
         }
         if (isMoved) {
             isRunning = true