feat: 优化代码

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

@@ -3,7 +3,9 @@ package io.legado.app.ui.book.read.page.delegate
 import android.graphics.*
 import android.graphics.drawable.GradientDrawable
 import android.os.Build
+import android.view.MotionEvent
 import io.legado.app.ui.book.read.page.PageView
+import io.legado.app.utils.screenshot
 import kotlin.math.*
 
 @Suppress("DEPRECATION")
@@ -74,6 +76,9 @@ class SimulationPageDelegate(pageView: PageView) : HorizontalPageDelegate(pageVi
         )
         cm.set(array)
         mColorMatrixFilter = ColorMatrixColorFilter(cm)
+
+        touchX = 0.01f //不让x,y为0,否则在点计算时会有问题
+        touchY = 0.01f
     }
 
     override fun setStartPoint(x: Float, y: Float, invalidate: Boolean) {
@@ -100,6 +105,48 @@ class SimulationPageDelegate(pageView: PageView) : HorizontalPageDelegate(pageVi
         }
     }
 
+    override fun onScroll(
+        e1: MotionEvent,
+        e2: MotionEvent,
+        distanceX: Float,
+        distanceY: Float
+    ): Boolean {
+        if (!isMoved) {
+            val event = e1.toAction(MotionEvent.ACTION_UP)
+            curPage.dispatchTouchEvent(event)
+            event.recycle()
+            if (abs(distanceX) > abs(distanceY)) {
+                if (distanceX < 0) {
+                    //如果上一页不存在
+                    if (!hasPrev()) {
+                        noNext = true
+                        return true
+                    }
+                    //上一页截图
+                    prevBitmap = prevPage.screenshot()
+                    curBitmap = curPage.screenshot()
+                } else {
+                    //如果不存在表示没有下一页了
+                    if (!hasNext()) {
+                        noNext = true
+                        return true
+                    }
+                    //下一页截图
+                    nextBitmap = nextPage.screenshot()
+                    curBitmap = curPage.screenshot()
+                }
+                isMoved = true
+            }
+        }
+        if (isMoved) {
+            isCancel = if (direction == Direction.NEXT) distanceX < 0 else distanceX > 0
+            isRunning = true
+            //设置触摸点
+            setTouchPoint(e2.x, e2.y)
+        }
+        return isMoved
+    }
+
     override fun onScrollStart() {
         val distanceX: Float
         when (direction) {
@@ -132,10 +179,9 @@ class SimulationPageDelegate(pageView: PageView) : HorizontalPageDelegate(pageVi
     }
 
     override fun onDraw(canvas: Canvas) {
-        bitmap?.let {
         if (direction === Direction.NEXT) {
             calcPoints()
-                drawCurrentPageArea(canvas, curBitmap, mPath0) //绘制翻页时的正面页
+            drawCurrentPageArea(canvas, curBitmap, mPath0)
             drawNextPageAreaAndShadow(canvas, nextBitmap)
             drawCurrentPageShadow(canvas)
             drawCurrentBackArea(canvas, curBitmap)
@@ -147,7 +193,6 @@ class SimulationPageDelegate(pageView: PageView) : HorizontalPageDelegate(pageVi
             drawCurrentBackArea(canvas, prevBitmap)
         }
     }
-    }
 
     /**
      * 创建阴影的GradientDrawable
@@ -404,6 +449,7 @@ class SimulationPageDelegate(pageView: PageView) : HorizontalPageDelegate(pageVi
         canvas.restore()
     }
 
+    //绘制翻页时的正面页
     private fun drawCurrentPageArea(
         canvas: Canvas,
         bitmap: Bitmap?,