feat: 优化代码

app/src/main/java/io/legado/app/ui/book/read/ReadBookActivity.kt

@@ -621,6 +621,7 @@ class ReadBookActivity : VMBaseActivity<ReadBookViewModel>(R.layout.activity_boo
         super.onDestroy()
         mHandler.removeCallbacks(keepScreenRunnable)
         textActionMenu?.dismiss()
+        page_view.pageDelegate?.onDestroy()
     }
 
     override fun observeLiveBus() {

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

@@ -91,6 +91,7 @@ class PageView(context: Context, attrs: AttributeSet) :
     }
 
     fun upPageAnim(pageAnim: Int) {
+        pageDelegate?.onDestroy()
         pageDelegate = null
         pageDelegate = when (pageAnim) {
             0 -> CoverPageDelegate(this)

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

@@ -323,6 +323,10 @@ abstract class PageDelegate(protected val pageView: PageView) :
         return hasNext
     }
 
+    open fun onDestroy() {
+        bitmap?.recycle()
+    }
+
     enum class Direction {
         NONE, PREV, NEXT
     }

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

@@ -2,37 +2,19 @@ package io.legado.app.ui.book.read.page.delegate
 
 import android.graphics.Canvas
 import android.view.MotionEvent
+import android.view.VelocityTracker
 import io.legado.app.ui.book.read.page.PageView
 import kotlin.math.abs
 
 class ScrollPageDelegate(pageView: PageView) : PageDelegate(pageView) {
 
+    // 滑动追踪的时间
+    private val VELOCITY_DURATION = 1000
+    //速度追踪器
+    private val mVelocity: VelocityTracker = VelocityTracker.obtain()
+
     override fun onAnimStart() {
-        if (!atTop && !atBottom) {
-            stopScroll()
-            return
-        }
-        val distanceY: Float
-        when (mDirection) {
-            Direction.NEXT -> distanceY =
-                if (isCancel) {
-                    var dis = viewHeight - startY + touchY
-                    if (dis > viewHeight) {
-                        dis = viewHeight.toFloat()
-                    }
-                    viewHeight - dis
-                } else {
-                    -(touchY + (viewHeight - startY))
-                }
-            else -> distanceY =
-                if (isCancel) {
-                    -(touchY - startY)
-                } else {
-                    viewHeight - (touchY - startY)
-                }
-        }
 
-        startScroll(0, touchY.toInt(), 0, distanceY.toInt())
     }
 
     override fun onDraw(canvas: Canvas) {
@@ -45,6 +27,11 @@ class ScrollPageDelegate(pageView: PageView) : PageDelegate(pageView) {
         }
     }
 
+    override fun onDown(e: MotionEvent): Boolean {
+        mVelocity.clear()
+        return super.onDown(e)
+    }
+
     override fun onScroll(
         e1: MotionEvent,
         e2: MotionEvent,
@@ -94,4 +81,9 @@ class ScrollPageDelegate(pageView: PageView) : PageDelegate(pageView) {
         return isMoved
     }
 
+
+    override fun onDestroy() {
+        super.onDestroy()
+        mVelocity.recycle()
+    }
 }