Nested scrollview in Android

Original article:

Scrollview nested scrollview
Http://www.eoeandroid.com/thread-240709-1-1.html

 

As we all know, two scrollviews in the same direction in Android cannot be nested. What if there is such a requirement? (This requirement is generally raised by people who do not understand Android)

Is it true that it cannot be nested? Of course you can. As long as you write another scrollview and set the foot in it, it supports nesting.

Currently, only two scrollviews can be nested, and more than two views need to be improved. This can meet many requirements. In addition, we only support the vertical scrollview, I am not eager to do this horizontally.

Effect:

First go to the coreCodeRight. I added comments in the code for your convenience.

 Package  Com. Sun. Shine. Study. innerscrollview. view;  Import  Android. content. context;  Import  Android. util. attributeset; Import  Android. View. motionevent;  Import  Android. View. view;  Import  Android. widget. scrollview;  Public   Class Innerscrollview Extends  Scrollview {  /**       */      Public  Scrollview parentscrollview;  Public Innerscrollview (context, attributeset attrs ){  Super  (Context, attrs );}  Private   Int Lastscrolldelta = 0 ;  Public   Void  Resume () {overscrollby ( 0,-lastscrolldelta, 0, getscrolly (), 0, getscrollrange (), 0, 0, True  ); Lastscrolldelta = 0 ;}  Int MTop = 10 ;  /**  * Roll targetview to the top  */      Public   Void  Scrollto (view targetview ){  Int Oldscrolly = Getscrolly ();  Int Top = targetview. gettop ()- MTop;  Int Delaty = Top- Oldscrolly; lastscrolldelta =Delaty; overscrollby ( 0, delaty, 0, getscrolly (), 0, getscrollrange (), 0, 0, True  );}  Private   Int  Getscrollrange (){  Int Scrollrange = 0 ;  If (Getchildcount ()> 0 ) {View child = Getchildat (0 ); Scrollrange = Math. Max (0, child. getheight ()-(Getheight ()));}  Return  Scrollrange ;}  Int  Currenty; @ override  Public   Boolean  Onintercepttouchevent (motionevent eV ){  If (Parentscrollview = Null  ){  Return   Super  . Onintercepttouchevent (EV );} Else  {  If (EV. getaction () = Motionevent. action_down ){  //  Blocks the rolling event of the parent scrollview Currenty = ( Int  ) EV. Gety (); setparentscrollable (  False  );  Return   Super  . Onintercepttouchevent (EV );} Else   If (EV. getaction () = Motionevent. action_up ){  //  Restore the rolling event to the parent scrollview Setparentscrollable ( True  );}  Else   If (EV. getaction () = Motionevent. action_move ){}}  Return   Super  . Onintercepttouchevent (EV) ;}@ override Public   Boolean  Ontouchevent (motionevent eV) {view child = Getchildat (0 );  If (Parentscrollview! = Null  ){  If (EV. getaction () = Motionevent. action_move ){  Int Height = Child. getmeasuredheight (); Height = Height- Getmeasuredheight (); //  System. Out. println ("Height =" + height );                  Int Scrolly = Getscrolly ();  //  System. Out. println ("scrolly" + scrolly );                  Int Y = ( Int  ) EV. Gety ();  //  Slide your finger down                  If (Currenty < Y ){  If (Scrolly <= 0 ){  //  If you scroll down to the header, the scroll is handed over to the parent scrollview. Setparentscrollable ( True  );  Return   False  ;}  Else  {Setparentscrollable (  False  );}}  Else  If (Currenty> Y ){  If (Scrolly> = Height ){  //  If you slide upwards to the header, the scroll is handed over to the parent scrollview. Setparentscrollable ( True  );  Return   False  ;}  Else  {Setparentscrollable ( False  ) ;}} Currenty = Y ;}}  Return   Super  . Ontouchevent (EV );}  /**  * Whether to give the rolling event to the parent scrollview **  @ Param  Flag  */      Private   Void Setparentscrollable ( Boolean Flag) {parentscrollview. requestdisallowintercepttouchevent ( ! Flag );}}