"Как я перестал бояться и полюбил кастомные View" —...

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ViewGroups

! FrameLayout

! LinearLayout

! RelativeLayout

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View positioning

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View positioning

! onMeasure

! onLayout

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onMeasure

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MeasureSpec

!  Mode

–  EXACTLY –  AT_MOST –  UNSPECIFIED !  Size

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MeasureSpec modes

!  EXACTLY

–  layout_width=“200dip” –  layout_height=“match_parent” –  layout_weight=“1”

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MeasureSpec modes

!  AT_MOST

–  layout_width=“wrap_content”

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MeasureSpec modes

!  UNSPECIFIED

–  ScrollView, ListView

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onMeasure

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onLayout

! getMeasuredWidth()

! getMeasuredHeight()

!  сhild.layout(left, top, right, bottom);

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–  How?

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–  How?

–  LayoutParams!

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attrs.xml

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main.xml

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LayoutParams

! ViewGroup.LayoutParams

! LinearLayout.LayoutParams

! RelativeLayout.LayoutParams

!  …

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LayoutParams

! checkLayoutParams(ViewGroup.LayoutParams p)

! generateDefaultLayoutParams()

! generateLayoutParams(ViewGroup.LayoutParams p);

! generateLayoutParams(AttributeSet attrs)

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PavementLayout.LayoutParams

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onMeasure

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View interactions

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Yandex.Maps search card

Motion directions !  Up !  Left & right !  Down

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Yandex.Maps search card heirarchy

CardSlidingDrawer

ViewPager

Card

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Touch events

1.  dispatchTouchEvent

2.  onInterceptTouchEvent

3.  children.dispatchTouchEvent

4.  onTouchEvent

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Touch events sample #1

CardSlidingDrawer

TextView

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Touch events sample #1

1.  dispatchTouchEvent CardSlidingDrawer

TextView

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Touch events sample #1

1.  dispatchTouchEvent

2.  onInterceptTouchEvent

CardSlidingDrawer

TextView

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Touch events sample #1

1.  dispatchTouchEvent

2.  onInterceptTouchEvent

3.  dispatchTouchEvent

CardSlidingDrawer

TextView

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Touch events sample #1

1.  dispatchTouchEvent

2.  onInterceptTouchEvent

3.  dispatchTouchEvent

4.  onTouchEvent

CardSlidingDrawer

TextView

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Touch events sample #1

1.  dispatchTouchEvent

2.  onInterceptTouchEvent

3.  dispatchTouchEvent

4.  onTouchEvent

CardSlidingDrawer

TextView

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Touch events sample #1

1.  dispatchTouchEvent

2.  onInterceptTouchEvent

3.  dispatchTouchEvent

4.  onTouchEvent

CardSlidingDrawer

TextView

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Touch events sample #2

1.  dispatchTouchEvent CardSlidingDrawer

Clickable TextView

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Touch events sample #2

1.  dispatchTouchEvent

2.  onInterceptTouchEvent

CardSlidingDrawer

Clickable TextView

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Touch events sample #2

1.  dispatchTouchEvent

2.  onInterceptTouchEvent

3.  dispatchTouchEvent

CardSlidingDrawer

Clickable TextView

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Touch events sample #2

1.  dispatchTouchEvent

2.  onInterceptTouchEvent

3.  dispatchTouchEvent

CardSlidingDrawer

Clickable TextView

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Touch events sample #2

1.  dispatchTouchEvent

2.  onInterceptTouchEvent

3.  dispatchTouchEvent

CardSlidingDrawer

Clickable TextView

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Touch events sample #2

1.  dispatchTouchEvent

2.  onInterceptTouchEvent

3.  dispatchTouchEvent

CardSlidingDrawer

Clickable TextView

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Touch events sample #2

1.  dispatchTouchEvent

2.  onInterceptTouchEvent

3.  dispatchTouchEvent

CardSlidingDrawer

Clickable TextView

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Touch events sample #2

1.  dispatchTouchEvent

2.  onInterceptTouchEvent

3.  dispatchTouchEvent

CardSlidingDrawer

Clickable TextView

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Touch events sample #2

1.  dispatchTouchEvent

2.  onInterceptTouchEvent

3.  dispatchTouchEvent

4.  onTouchEvent

CardSlidingDrawer

Clickable TextView

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Touch events sample #2

1.  dispatchTouchEvent

2.  onInterceptTouchEvent

3.  dispatchTouchEvent

4.  onTouchEvent

CardSlidingDrawer

Clickable TextView

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Touch events sample #2

1.  dispatchTouchEvent

2.  onInterceptTouchEvent

3.  dispatchTouchEvent

4.  onTouchEvent

CardSlidingDrawer

Clickable TextView

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TouchSlop

! deltaY = Math.abs( event.getY() – startY );

! ViewConfiguration.getScaledTouchSlop();

! view.scrollTo(x,y);

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VelocityTracker

! VelocityTracker.obtain();

! VelocityTracker.addMovement( event );

! VelocityTracker.computeCurrentVelocity(units);

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Scroller

!  void fling(…);

!  void View.computeScroll();

! boolean computeScrollOffset();

! int getCurrY();

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Scroller

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Wrap-up

! onMeasure & onLayout

! onIntercept & onTouchEvent

! GestureDetector & DragHelper

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Samples

https://github.com/ArikonUA/yac13

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Спасибо за внимание

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Поляков Алексей Разработчик

alexpolyakov@yandex-team.ru

!   @arikon