Android Custom Touch Handling

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Transcript

1. Android Touch Handling Tin Tran Siclo-mobile
2. WHY? ScrollView LiNEARLAYOUT SCROLLVIEW
3. Built-in Touch FrameWork
4. Activity ImageView dispatchTouchEvent() dispatchTouchEvent() onTouchEvent() View.OnTouchListener.onTouch() onTouchEvent()
5. Activity delivers touch events to the view root;
6. Activity Button dispatchTouchEvent() dispatchTouchEvent() onTouchEvent() View.OnTouchListener.onTouch() onTouchEvent()
7. Activity ViewGroup dispatchTouchEvent() dispatchTouchEvent() onTouchEvent() VieW dispatchTouchEvent() onTouchEvent() OnTouchListener.onTouch() OnTouchListener.onTouch() onTouchEvent()
8. ViewGroup delivers TouchEvents to child views;
9. public boolean dispatchTouchEvent(MotionEvent ev) { for(View child : childrenViews) { if(child.dispatchTouchEvent(ev)) { return true; } } return super.dispatchTouchEvent(ev); } ViewGroup - dispatchTouchEvent
10. View.java - dispatchTouchEvent if (!result && onTouchEvent(event)) { result = true; } if (mOnTouchListener != null && mOnTouchListener.onTouch(this, event)) { result = true; } public boolean dispatchTouchEvent(MotionEvent event) { result = false; return result; }
11. ViewGroup dispatchTouchEvent() OnTouchListener.onTouch() VieW onTouchEvent() dispatchTouchEvent() OnTouchListener.onTouch() onTouchEvent() onInterceptTouchEvent() False True
12. return super.dispatchTouchEvent(ev); } ViewGroup - dispatchTouchEvent - with intercept public boolean dispatchTouchEvent(MotionEvent ev) { for(View child : children){
 if(child.dispatchTouchEvent(ev)) return true; } if(!onInterceptTouchEvent()){ }
13. What is A Touch Event? ACTION_DOWN ACTION_MOVE ACTION_UP ACTION_CANCEL int masked = ev.getActionMasked(ev)
14. What is A Touch Event? motionEvent.getX() motionEvent.getY() motionEvent.getRawX() motionEvent.getRawY() motionEvent.getHistoricalX() motionEvent.getHistoricalY()
15. public static void main(String[] args){ for( int i = 0; i >= 0; i++){ System.out.println(“Demos"); } }