Android Touch Event派发分析

早前画了touch事件派发草图，重新整理了下

Touch Event: Down

Down事件，无论 clickable 与否都会各层级传递

Touch Event: Move

Hierarchy	clickable/longClickable
Parent	false
Child	false

Hierarchy	clickable/longClickable
Parent	false/true
Child	true

Hierarchy	clickable/longClickable
Parent	true
Child	false

Touch Event: Up

Hierarchy	clickable/longClickable
Parent	false
Child	false

Hierarchy	clickable/longClickable
Parent	true/false
Child	true

Hierarchy	clickable/longClickable
Parent	true
Child	false

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