How to implement custom LayoutManager

https://github.com/MoyuruAizawa/TimetableLayout

Transcript

1. -BZPVU.BOBHFSͷ࣮૷ํ๏ @MoyuruAizawa
2. MoyuruAizawa Moyuru Aizawa
 Software engineer of CATS Div. CyberAgent Inc. 
 Previously at Pairs Div. Eureka Inc.
3. .PZVSV"J[BXB5JNFUBCMF-BZPVU http://bit.ly/ttlayout
4. ‣ -BZPVU.BOBHFSͷ֓ཁ
   ‣ ؆қ-JOFBS-BZPVU.BOBHFSΛྫʹ࣮૷ํ๏ ࠓ೔࿩͢͜ͱ
5. ‣ 3FDZDMFS7JFXͷDIJME
   WJFXTͷϨΠΞ΢τΛ୲౰͢ΔϞδϡʔϧ
   ‣ -BZPVU.BOBHFSΛม͑Δ͜ͱͰ༷ʑͳϨΠΞ΢τΛ࣮ݱ͢Δࣄ͕Ͱ͖ Δ -BZPVU.BOBHFSͷ֓ཁ
6. ‣ ؔ਺ػೳ͕ଟ͍ͷͰ͔ͳΓେม
   ‣ ϨΠΞ΢τͷෳࡶ͞Λ૿͢ཁૉ
   ‣ 0SJFOUBUJPO
   7FSUJDBM
   -BZPVU
   
   )PSJ[POUBM
   -BZPVU
   ‣ 3FWFSTF-BZPVU
   ‣ -5335- -BZPVU.BOBHFSͷ࣮૷͸େม
7. ‣ PO-BZPVU$IJMESFO
   ‣ TDSPMM7FSUJDBMMZ#Z
   
   TDSPMM)PSJ[POUBMMZ#Z
   ‣ TDSPMM5P
   ‣ TNPPUI4DSPMM5P
   ‣ DPNQVUF7FSUJDBM4DSPMM&YUFOU
   
   DPNQVUF)PSJ[POUBM4DSPMM&YUFOU
   ‣ DPNQVUF7FSUJDBM4DSPMM0GGTFU
   
   DPNQVUF)PSJ[POUBM4DSPMM0GGTFU
   ‣ DPNQVUF7FSUJDBM4DSPMM3BOHF
   
   DPNQVUF)PSJ[POUBM4DSPMM3BOHF
   ‣ *UFN
   1SFGFUDI
   ‣ *UFN
   %FDPSBUJPOT
   ‣ *UFN
   "OJNBUPST
   ‣ 1SFEJDUJWF
   "OJNBUJPOT
   ‣ ʜ -BZPVU.BOBHFSͷؔ਺ػೳ
8. ‣ PO-BZPVU$IJMESFO
   ‣ TDSPMM7FSUJDBMMZ#Z
   
   TDSPMM)PSJ[POUBMMZ#Z
   ‣ TDSPMM5P
   ‣ TNPPUI4DSPMM5P
   ‣ DPNQVUF7FSUJDBM4DSPMM&YUFOU
   
   DPNQVUF)PSJ[POUBM4DSPMM&YUFOU
   ‣ DPNQVUF7FSUJDBM4DSPMM0GGTFU
   
   DPNQVUF)PSJ[POUBM4DSPMM0GGTFU
   ‣ DPNQVUF7FSUJDBM4DSPMM3BOHF
   
   DPNQVUF)PSJ[POUBM4DSPMM3BOHF
   ‣ *UFN
   1SFGFUDI
   ‣ *UFN
   %FDPSBUJPOT
   ‣ *UFN
   "OJNBUPST
   ‣ 1SFEJDUJWF
   "OJNBUJPOT
   ‣ ʜ -BZPVU.BOBHFSͷؔ਺ػೳ
9. ‣ PO-BZPVU$IJMESFO
   ‣ TDSPMM7FSUJDBMMZ#Z
   
   TDSPMM)PSJ[POUBMMZ#Z
   ‣ TDSPMM5P
   ‣ TNPPUI4DSPMM5P
   ‣ DPNQVUF7FSUJDBM4DSPMM&YUFOU
   
   DPNQVUF)PSJ[POUBM4DSPMM&YUFOU
   ‣ DPNQVUF7FSUJDBM4DSPMM0GGTFU
   
   DPNQVUF)PSJ[POUBM4DSPMM0GGTFU
   ‣ DPNQVUF7FSUJDBM4DSPMM3BOHF
   
   DPNQVUF)PSJ[POUBM4DSPMM3BOHF
   ‣ *UFN
   1SFGFUDI
   ‣ *UFN
   %FDPSBUJPOT
   ‣ *UFN
   "OJNBUPST
   ‣ 1SFEJDUJWF
   "OJNBUJPOT
   ‣ ʜ -BZPVU.BOBHFSͷؔ਺ػೳ
10. ‣ PO-BZPVU$IJMESFO
    ‣ TDSPMM7FSUJDBMMZ#Z
    
    TDSPMM)PSJ[POUBMMZ#Z
    ‣ TDSPMM5P
    ‣ TNPPUI4DSPMM5P
    ‣ DPNQVUF7FSUJDBM4DSPMM&YUFOU
    
    DPNQVUF)PSJ[POUBM4DSPMM&YUFOU
    ‣ DPNQVUF7FSUJDBM4DSPMM0GGTFU
    
    DPNQVUF)PSJ[POUBM4DSPMM0GGTFU
    ‣ DPNQVUF7FSUJDBM4DSPMM3BOHF
    
    DPNQVUF)PSJ[POUBM4DSPMM3BOHF
    ‣ *UFN
    1SFGFUDI
    ‣ *UFN
    %FDPSBUJPOT
    ‣ *UFN
    "OJNBUPST
    ‣ 1SFEJDUJWF
    "OJNBUJPOT
    ‣ ʜ -BZPVU.BOBHFSͷؔ਺ػೳ
11. ‣ PO-BZPVU$IJMESFO
    ‣ TDSPMM7FSUJDBMMZ#Z
    
    TDSPMM)PSJ[POUBMMZ#Z
    ‣ TDSPMM5P
    ‣ TNPPUI4DSPMM5P
    ‣ DPNQVUF7FSUJDBM4DSPMM&YUFOU
    
    DPNQVUF)PSJ[POUBM4DSPMM&YUFOU
    ‣ DPNQVUF7FSUJDBM4DSPMM0GGTFU
    
    DPNQVUF)PSJ[POUBM4DSPMM0GGTFU
    ‣ DPNQVUF7FSUJDBM4DSPMM3BOHF
    
    DPNQVUF)PSJ[POUBM4DSPMM3BOHF
    ‣ *UFN
    1SFGFUDI
    ‣ *UFN
    %FDPSBUJPOT
    ‣ *UFN
    "OJNBUPST
    ‣ 1SFEJDUJWF
    "OJNBUJPOT
    ‣ ʜ -BZPVU.BOBHFSͷؔ਺ػೳ
12. ‣ PO-BZPVU$IJMESFO
    ‣ TDSPMM7FSUJDBMMZ#Z
    
    TDSPMM)PSJ[POUBMMZ#Z
    ‣ TDSPMM5P
    ‣ TNPPUI4DSPMM5P
    ‣ DPNQVUF7FSUJDBM4DSPMM&YUFOU
    
    DPNQVUF)PSJ[POUBM4DSPMM&YUFOU
    ‣ DPNQVUF7FSUJDBM4DSPMM0GGTFU
    
    DPNQVUF)PSJ[POUBM4DSPMM0GGTFU
    ‣ DPNQVUF7FSUJDBM4DSPMM3BOHF
    
    DPNQVUF)PSJ[POUBM4DSPMM3BOHF
    ‣ *UFN
    1SFGFUDI
    ‣ *UFN
    %FDPSBUJPOT
    ‣ *UFN
    "OJNBUPST
    ‣ 1SFEJDUJWF
    "OJNBUJPOT
    ‣ ʜ -BZPVU.BOBHFSͷؔ਺ػೳ
13. ‣ PO-BZPVU$IJMESFO
    ‣ TDSPMM7FSUJDBMMZ#Z
    
    TDSPMM)PSJ[POUBMMZ#Z
    ‣ TDSPMM5P
    ‣ TNPPUI4DSPMM5P
    ‣ DPNQVUF7FSUJDBM4DSPMM&YUFOU
    
    DPNQVUF)PSJ[POUBM4DSPMM&YUFOU
    ‣ DPNQVUF7FSUJDBM4DSPMM0GGTFU
    
    DPNQVUF)PSJ[POUBM4DSPMM0GGTFU
    ‣ DPNQVUF7FSUJDBM4DSPMM3BOHF
    
    DPNQVUF)PSJ[POUBM4DSPMM3BOHF
    ‣ *UFN
    1SFGFUDI
    ‣ *UFN
    %FDPSBUJPOT
    ‣ *UFN
    "OJNBUPST
    ‣ 1SFEJDUJWF
    "OJNBUJPOT
    ‣ ʜ -BZPVU.BOBHFSͷؔ਺ػೳ
14. ‣ ϨΠΞ΢τͷॳظԽ
    ‣ BEBQUFS
    DIBOHF
    ‣ SFRVFTU-BZPVU
    ‣ ্͔Βॱ൪ʹϨΠΞ΢τ͍ͯ͘͠ PO-BZPVU$IJMESFO
15. private fun addRow(position: Int, offsetY: Int, isAppend: Boolean, recycler: Recycler): Int { val view = recycler.getViewForPosition(position) addView(view, if (isAppend) -1 else 0) measureChildWithMargins(view, 0, 0) val height = getDecoratedMeasuredHeight(view) val width = getDecoratedMeasuredWidth(view) val top = if (isAppend) offsetY else offsetY - height val bottom = top + height layoutDecoratedWithMargins( view, parentLeft, top, parentLeft + width, bottom) return height } PO-BZPVU$IJMESFO
16. private fun addRow(position: Int, offsetY: Int, isAppend: Boolean, recycler: Recycler): Int { val view = recycler.getViewForPosition(position) addView(view, if (isAppend) -1 else 0) measureChildWithMargins(view, 0, 0) val height = getDecoratedMeasuredHeight(view) val width = getDecoratedMeasuredWidth(view) val top = if (isAppend) offsetY else offsetY - height val bottom = top + height layoutDecoratedWithMargins( view, parentLeft, top, parentLeft + width, bottom) return height } PO-BZPVU$IJMESFO
17. private fun addRow(position: Int, offsetY: Int, isAppend: Boolean, recycler: Recycler): Int { val view = recycler.getViewForPosition(position) addView(view, if (isAppend) -1 else 0) measureChildWithMargins(view, 0, 0) val height = getDecoratedMeasuredHeight(view) val width = getDecoratedMeasuredWidth(view) val top = if (isAppend) offsetY else offsetY - height val bottom = top + height layoutDecoratedWithMargins( view, parentLeft, top, parentLeft + width, bottom) return height } PO-BZPVU$IJMESFO
18. private fun addRow(position: Int, offsetY: Int, isAppend: Boolean, recycler: Recycler): Int { val view = recycler.getViewForPosition(position) addView(view, if (isAppend) -1 else 0) measureChildWithMargins(view, 0, 0) val height = getDecoratedMeasuredHeight(view) val width = getDecoratedMeasuredWidth(view) val top = if (isAppend) offsetY else offsetY - height val bottom = top + height layoutDecoratedWithMargins( view, parentLeft, top, parentLeft + width, bottom) return height } PO-BZPVU$IJMESFO
19. private fun addRow(position: Int, offsetY: Int, isAppend: Boolean, recycler: Recycler): Int { val view = recycler.getViewForPosition(position) addView(view, if (isAppend) -1 else 0) measureChildWithMargins(view, 0, 0) val height = getDecoratedMeasuredHeight(view) val width = getDecoratedMeasuredWidth(view) val top = if (isAppend) offsetY else offsetY - height val bottom = top + height layoutDecoratedWithMargins( view, parentLeft, top, parentLeft + width, bottom) return height } PO-BZPVU$IJMESFO
20. private fun addRow(position: Int, offsetY: Int, isAppend: Boolean, recycler: Recycler): Int { val view = recycler.getViewForPosition(position) addView(view, if (isAppend) -1 else 0) measureChildWithMargins(view, 0, 0) val height = getDecoratedMeasuredHeight(view) val width = getDecoratedMeasuredWidth(view) val top = if (isAppend) offsetY else offsetY - height val bottom = top + height layoutDecoratedWithMargins( view, parentLeft, top, parentLeft + width, bottom) return height } PO-BZPVU$IJMESFO
21. private fun addRow(position: Int, offsetY: Int, isAppend: Boolean, recycler: Recycler): Int { val view = recycler.getViewForPosition(position) addView(view, if (isAppend) -1 else 0) measureChildWithMargins(view, 0, 0) val height = getDecoratedMeasuredHeight(view) val width = getDecoratedMeasuredWidth(view) val top = if (isAppend) offsetY else offsetY - height val bottom = top + height layoutDecoratedWithMargins( view, parentLeft, top, parentLeft + width, bottom) return height } PO-BZPVU$IJMESFO
22. private fun addRow(position: Int, offsetY: Int, isAppend: Boolean, recycler: Recycler): Int { val view = recycler.getViewForPosition(position) addView(view, if (isAppend) -1 else 0) measureChildWithMargins(view, 0, 0) val height = getDecoratedMeasuredHeight(view) val width = getDecoratedMeasuredWidth(view) val top = if (isAppend) offsetY else offsetY - height val bottom = top + height layoutDecoratedWithMargins( view, parentLeft, top, parentLeft + width, bottom) return height } PO-BZPVU$IJMESFO
23. private fun addRow(position: Int, offsetY: Int, isAppend: Boolean, recycler: Recycler): Int { val view = recycler.getViewForPosition(position) addView(view, if (isAppend) -1 else 0) measureChildWithMargins(view, 0, 0) val height = getDecoratedMeasuredHeight(view) val width = getDecoratedMeasuredWidth(view) val top = if (isAppend) offsetY else offsetY - height val bottom = top + height layoutDecoratedWithMargins( view, parentLeft, top, parentLeft + width, bottom) return height } PO-BZPVU$IJMESFO
24. private fun addRow(position: Int, offsetY: Int, isAppend: Boolean, recycler: Recycler): Int { val view = recycler.getViewForPosition(position) addView(view, if (isAppend) -1 else 0) measureChildWithMargins(view, 0, 0) val height = getDecoratedMeasuredHeight(view) val width = getDecoratedMeasuredWidth(view) val top = if (isAppend) offsetY else offsetY - height val bottom = top + height layoutDecoratedWithMargins( view, parentLeft, top, parentLeft + width, bottom) return height } PO-BZPVU$IJMESFO
25. private fun fillChunk(startPosition: Int, startY: Int, isAppend: Boolean, recycler: Recycler) { val remainingSpace = if (isAppend) parentBottom - startY else startY - parentTop var offsetY = startY val range = if (isAppend) startPosition until itemCount else startPosition downTo 0 for (position in range) { val height = addRow(position, offsetY, isAppend, recycler) offsetY += if (isAppend) height else -height val consumed = abs(offsetY - startY) if (consumed > remainingSpace) break } } PO-BZPVU$IJMESFO
26. private fun fillChunk(startPosition: Int, startY: Int, isAppend: Boolean, recycler: Recycler) { val remainingSpace = if (isAppend) parentBottom - startY else startY - parentTop var offsetY = startY val range = if (isAppend) startPosition until itemCount else startPosition downTo 0 for (position in range) { val height = addRow(position, offsetY, isAppend, recycler) offsetY += if (isAppend) height else -height val consumed = abs(offsetY - startY) if (consumed > remainingSpace) break } } PO-BZPVU$IJMESFO
27. private fun fillChunk(startPosition: Int, startY: Int, isAppend: Boolean, recycler: Recycler) { val remainingSpace = if (isAppend) parentBottom - startY else startY - parentTop var offsetY = startY val range = if (isAppend) startPosition until itemCount else startPosition downTo 0 for (position in range) { val height = addRow(position, offsetY, isAppend, recycler) offsetY += if (isAppend) height else -height val consumed = abs(offsetY - startY) if (consumed > remainingSpace) break } } PO-BZPVU$IJMESFO
28. private fun fillChunk(startPosition: Int, startY: Int, isAppend: Boolean, recycler: Recycler) { val remainingSpace = if (isAppend) parentBottom - startY else startY - parentTop var offsetY = startY val range = if (isAppend) startPosition until itemCount else startPosition downTo 0 for (position in range) { val height = addRow(position, offsetY, isAppend, recycler) offsetY += if (isAppend) height else -height val consumed = abs(offsetY - startY) if (consumed > remainingSpace) break } } PO-BZPVU$IJMESFO
29. override fun onLayoutChildren(recycler: Recycler, state: State) { if (itemCount == 0) { detachAndScrapAttachedViews(recycler) return } val restoredFirstVisibleView = getChildAt(0) val restoredPosition = restoredFirstVisibleView?.adapterPosition val restoredTop = restoredFirstVisibleView?.let(this::getDecoratedTop) if (childCount > 0) detachAndScrapAttachedViews(recycler) fillChunk(restoredPosition ?: 0, restoredTop ?: parentTop, isAppend = true, recycler = recycler) } PO-BZPVU$IJMESFO
30. override fun onLayoutChildren(recycler: Recycler, state: State) { if (itemCount == 0) { detachAndScrapAttachedViews(recycler) return } val restoredFirstVisibleView = getChildAt(0) val restoredPosition = restoredFirstVisibleView?.adapterPosition val restoredTop = restoredFirstVisibleView?.let(this::getDecoratedTop) if (childCount > 0) detachAndScrapAttachedViews(recycler) fillChunk(restoredPosition ?: 0, restoredTop ?: parentTop, isAppend = true, recycler = recycler) } PO-BZPVU$IJMESFO
31. override fun onLayoutChildren(recycler: Recycler, state: State) { if (itemCount == 0) { detachAndScrapAttachedViews(recycler) return } val restoredFirstVisibleView = getChildAt(0) val restoredPosition = restoredFirstVisibleView?.adapterPosition val restoredTop = restoredFirstVisibleView?.let(this::getDecoratedTop) if (childCount > 0) detachAndScrapAttachedViews(recycler) fillChunk(restoredPosition ?: 0, restoredTop ?: parentTop, isAppend = true, recycler = recycler) } PO-BZPVU$IJMESFO
32. override fun onLayoutChildren(recycler: Recycler, state: State) { if (itemCount == 0) { detachAndScrapAttachedViews(recycler) return } val restoredFirstVisibleView = getChildAt(0) val restoredPosition = restoredFirstVisibleView?.adapterPosition val restoredTop = restoredFirstVisibleView?.let(this::getDecoratedTop) if (childCount > 0) detachAndScrapAttachedViews(recycler) fillChunk(restoredPosition ?: 0, restoredTop ?: parentTop, isAppend = true, recycler = recycler) } PO-BZPVU$IJMESFO
33. override fun onSaveInstanceState(): Parcelable? { val firstVisibleItem = getChildAt(0) ?: return null return SavedState(firstVisibleItem.adapterPosition, getDecoratedTop(firstVisibleItem)) } override fun onRestoreInstanceState(state: Parcelable?) { savedState = state as? SavedState } PO-BZPVU$IJMESFO
34. val restoredFirstVisibleView = getChildAt(0) val restoredPosition = savedState?.firstVisibleItemPosition ?: restoredFirstVisibleView?.adapterPosition val restoredTop = savedState?.firstVisibleItemTop ?: restoredFirstVisibleView?.let(this::getDecoratedTop) if (childCount > 0) detachAndScrapAttachedViews(recycler) if (restoredPosition != null && restoredTop != null && restoredPosition < itemCount) fillChunk(restoredPosition, restoredTop, isAppend = true, recycler = recycler) else fillChunk(0, parentTop, isAppend = true, recycler = recycler) PO-BZPVU$IJMESFO
35. override fun onLayoutCompleted(state: State?) { savedState = null } PO-BZPVU$PNQMFUFE
36. ‣ DIJME
    WJFXTͷεϥΠυ
    ‣ ը໘͔Βग़ͨDIJME
    WJFXTͷSFNPWF
    ‣ ۭ͖εϖʔεʹDIJME
    WJFXTͷBEE TDSPMM7FSUJDBMMZ#Z
37. ‣ DIJME
    WJFXTͷεϥΠυ
    ‣ ը໘͔Βग़ͨDIJME
    WJFXTͷSFNPWF
    ‣ ۭ͖εϖʔεʹDIJME
    WJFXTͷBEE TDSPMM7FSUJDBMMZ#Z
38. ‣ DIJME
    WJFXTͷεϥΠυ
    ‣ ը໘͔Βग़ͨDIJME
    WJFXTͷSFNPWF
    ‣ ۭ͖εϖʔεʹDIJME
    WJFXTͷBEE TDSPMM7FSUJDBMMZ#Z
39. ‣ DIJME
    WJFXTͷεϥΠυ
    ‣ ը໘͔Βग़ͨDIJME
    WJFXTͷSFNPWF
    ‣ ۭ͖εϖʔεʹDIJME
    WJFXTͷBEE TDSPMM7FSUJDBMMZ#Z
40. private fun calculateActualDy(dy: Int): Int { if (dy == 0) return 0 return if (dy > 0) { // up swipe val lastView = getChildAt(childCount - 1) ?: return 0 val bottom = getDecoratedBottom(lastView) if (lastView.adapterPosition == itemCount - 1) if (bottom == parentBottom) 0 else min(bottom - parentBottom, dy) else dy } else { val firstView = getChildAt(0) ?: return 0 val top = getDecoratedTop(firstView) if (firstView.adapterPosition == 0) if (top == parentTop) 0 else max(top - parentTop, dy) else dy } } TDSPMM7FSUJDBMMZ#Z
41. private fun calculateActualDy(dy: Int): Int { if (dy == 0) return 0 return if (dy > 0) { // up swipe val lastView = getChildAt(childCount - 1) ?: return 0 val bottom = getDecoratedBottom(lastView) if (lastView.adapterPosition == itemCount - 1) if (bottom == parentBottom) 0 else min(bottom - parentBottom, dy) else dy } else { val firstView = getChildAt(0) ?: return 0 val top = getDecoratedTop(firstView) if (firstView.adapterPosition == 0) if (top == parentTop) 0 else max(top - parentTop, dy) else dy } } TDSPMM7FSUJDBMMZ#Z
42. private fun calculateActualDy(dy: Int): Int { if (dy == 0) return 0 return if (dy > 0) { // up swipe val lastView = getChildAt(childCount - 1) ?: return 0 val bottom = getDecoratedBottom(lastView) if (lastView.adapterPosition == itemCount - 1) if (bottom == parentBottom) 0 else min(bottom - parentBottom, dy) else dy } else { val firstView = getChildAt(0) ?: return 0 val top = getDecoratedTop(firstView) if (firstView.adapterPosition == 0) if (top == parentTop) 0 else max(top - parentTop, dy) else dy } } TDSPMM7FSUJDBMMZ#Z
43. private fun calculateActualDy(dy: Int): Int { if (dy == 0) return 0 return if (dy > 0) { // up swipe val lastView = getChildAt(childCount - 1) ?: return 0 val bottom = getDecoratedBottom(lastView) if (lastView.adapterPosition == itemCount - 1) if (bottom == parentBottom) 0 else min(bottom - parentBottom, dy) else dy } else { val firstView = getChildAt(0) ?: return 0 val top = getDecoratedTop(firstView) if (firstView.adapterPosition == 0) if (top == parentTop) 0 else max(top - parentTop, dy) else dy } } TDSPMM7FSUJDBMMZ#Z
44. private fun recycleTop(recycler: Recycler) { children.forEach { if (getDecoratedBottom(it) < parentTop) removeAndRecycleView(it, recycler) else return } } TDSPMM7FSUJDBMMZ#Z
45. private fun recycleTop(recycler: Recycler) { children.forEach { if (getDecoratedBottom(it) < parentTop) removeAndRecycleView(it, recycler) else return } } TDSPMM7FSUJDBMMZ#Z
46. private fun recycleTop(recycler: Recycler) { children.forEach { if (getDecoratedBottom(it) < parentTop) removeAndRecycleView(it, recycler) else return } } TDSPMM7FSUJDBMMZ#Z
47. override fun scrollVerticallyBy(dy: Int, recycler: Recycler, state: State): Int { val actualDy = calculateActualDy(dy) if (actualDy == 0) return 0 offsetChildrenVertical(-actualDy) if (actualDy > 0) { recycleTop(recycler) val lastView = getChildAt(childCount - 1) ?: return 0 val bottom = getDecoratedBottom(lastView) if (bottom < parentBottom) fillChunk(lastView.adapterPosition + 1, bottom, true, recycler) } else { … } return actualDy } TDSPMM7FSUJDBMMZ#Z
48. override fun scrollVerticallyBy(dy: Int, recycler: Recycler, state: State): Int { val actualDy = calculateActualDy(dy) if (actualDy == 0) return 0 offsetChildrenVertical(-actualDy) if (actualDy > 0) { recycleTop(recycler) val lastView = getChildAt(childCount - 1) ?: return 0 val bottom = getDecoratedBottom(lastView) if (bottom < parentBottom) fillChunk(lastView.adapterPosition + 1, bottom, true, recycler) } else { … } return actualDy } TDSPMM7FSUJDBMMZ#Z
49. override fun scrollVerticallyBy(dy: Int, recycler: Recycler, state: State): Int { val actualDy = calculateActualDy(dy) if (actualDy == 0) return 0 offsetChildrenVertical(-actualDy) if (actualDy > 0) { recycleTop(recycler) val lastView = getChildAt(childCount - 1) ?: return 0 val bottom = getDecoratedBottom(lastView) if (bottom < parentBottom) fillChunk(lastView.adapterPosition + 1, bottom, true, recycler) } else { … } return actualDy } TDSPMM7FSUJDBMMZ#Z
50. override fun scrollVerticallyBy(dy: Int, recycler: Recycler, state: State): Int { val actualDy = calculateActualDy(dy) if (actualDy == 0) return 0 offsetChildrenVertical(-actualDy) if (actualDy > 0) { recycleTop(recycler) val lastView = getChildAt(childCount - 1) ?: return 0 val bottom = getDecoratedBottom(lastView) if (bottom < parentBottom) fillChunk(lastView.adapterPosition + 1, bottom, true, recycler) } else { … } return actualDy } TDSPMM7FSUJDBMMZ#Z
51. override fun scrollVerticallyBy(dy: Int, recycler: Recycler, state: State): Int { val actualDy = calculateActualDy(dy) if (actualDy == 0) return 0 offsetChildrenVertical(-actualDy) if (actualDy > 0) { recycleTop(recycler) val lastView = getChildAt(childCount - 1) ?: return 0 val bottom = getDecoratedBottom(lastView) if (bottom < parentBottom) fillChunk(lastView.adapterPosition + 1, bottom, true, recycler) } else { … } return actualDy } TDSPMM7FSUJDBMMZ#Z
52. override fun scrollVerticallyBy(dy: Int, recycler: Recycler, state: State): Int { val actualDy = calculateActualDy(dy) if (actualDy == 0) return 0 offsetChildrenVertical(-actualDy) if (actualDy > 0) { recycleTop(recycler) val lastView = getChildAt(childCount - 1) ?: return 0 val bottom = getDecoratedBottom(lastView) if (bottom < parentBottom) fillChunk(lastView.adapterPosition + 1, bottom, true, recycler) } else { … } return actualDy } TDSPMM7FSUJDBMMZ#Z
53. ‣ ࢦఆϙδγϣϯͰMBZPVU͠௚͢ TDSPMM5P1PTJUJPO
54. override fun scrollToPosition(position: Int) { pendingScrollPosition = position requestLayout() } TDSPMM5P1PTJUJPO
55. override fun onLayoutChildren(recycler: Recycler, state: State) { … if (pendingScrollPosition != RecyclerView.NO_POSITION) { fillChunk(pendingScrollPosition, parentTop, true, recycler) val lastVisibleView = getChildAt(childCount - 1) ?: return val bottom = getDecoratedBottom(lastVisibleView) if (lastVisibleView.adapterPosition.isLast && bottom < parentBottom) fixLayoutGap() return } … } TDSPMM5P1PTJUJPO
56. override fun onLayoutChildren(recycler: Recycler, state: State) { … if (pendingScrollPosition != RecyclerView.NO_POSITION) { fillChunk(pendingScrollPosition, parentTop, true, recycler) val lastVisibleView = getChildAt(childCount - 1) ?: return val bottom = getDecoratedBottom(lastVisibleView) if (lastVisibleView.adapterPosition.isLast && bottom < parentBottom) fixLayoutGap() return } … } TDSPMM5P1PTJUJPO
57. override fun onLayoutChildren(recycler: Recycler, state: State) { … if (pendingScrollPosition != RecyclerView.NO_POSITION) { fillChunk(pendingScrollPosition, parentTop, true, recycler) val lastVisibleView = getChildAt(childCount - 1) ?: return val bottom = getDecoratedBottom(lastVisibleView) if (lastVisibleView.adapterPosition.isLast && bottom < parentBottom) fixLayoutGap() return } … } TDSPMM5P1PTJUJPO 99
58. override fun onLayoutChildren(recycler: Recycler, state: State) { … if (pendingScrollPosition != RecyclerView.NO_POSITION) { fillChunk(pendingScrollPosition, parentTop, true, recycler) val lastVisibleView = getChildAt(childCount - 1) ?: return val bottom = getDecoratedBottom(lastVisibleView) if (lastVisibleView.adapterPosition.isLast && bottom < parentBottom) fixLayoutGap() return } … } TDSPMM5P1PTJUJPO 99
59. override fun onLayoutChildren(recycler: Recycler, state: State) { … if (pendingScrollPosition != RecyclerView.NO_POSITION) { fillChunk(pendingScrollPosition, parentTop, true, recycler) val lastVisibleView = getChildAt(childCount - 1) ?: return val bottom = getDecoratedBottom(lastVisibleView) if (lastVisibleView.adapterPosition.isLast && bottom < parentBottom) fixLayoutGap() return } … } TDSPMM5P1PTJUJPO 99 98 97 96 95
60. ͻͨ͢ΒੵΈ໦Λ͍ͯ͘͠࡞ۀ Ͱ͢
61. 5IBOL
    ZPV