android中封锁返回键

android中关闭返回键
public boolean onKeyDown(int keyCode,KeyEvent event){
switch(keyCode){
case KeyEvent.KEYCODE_HOME:return true;
case KeyEvent.KEYCODE_BACK:return true;
case KeyEvent.KEYCODE_CALL:return true;
case KeyEvent.KEYCODE_SYM: return true;
case HTTP/1.1 404 Not FoundX-Runtime: 7Vary: Accept-EncodingContent-Type: text/html; charset=utf-8Cache-Control: no-cacheContent-Length: 1335Set-Cookie: _javaeye_cookie_id_=1413596337404617; domain=iteye.com; path=/; expires=Wed, 18-Oct-2017 01:38:57 GMTSet-Cookie: _javaeye3_session_=BAh7BjoPc2Vzc2lvbl9pZCIlNWYxZGRhZGUxNWI3OGExNjE3NzlkZDE5NWFhMDQ4ZDY%3D--f2a2f5520ce2ed67e5afbd103b07b5d164a55b3c; domain=.iteye.com; path=/; HttpOnlyDate: Sat, 18 Oct 2014 01:38:57 GMTServer: ITeye SERVER HTTP/1.1 200 OKCache-Control: private, max-age=0, must-revalidateSet-Cookie: _javaeye_cookie_id_=1413596337504958; domain=iteye.com; path=/; expires=Wed, 18-Oct-2017 01:38:57 GMTSet-Cookie: _javaeye3_session_=BAh7BjoPc2Vzc2lvbl9pZCIlM2RjYjMxOTg4NTMyZjAyNjUyZjk4MTE2OWM3YWM3Nzg%3D--cca00c87c2f9773199ccaa469844c3707a96c742; domain=.iteye.com; path=/; HttpOnlyContent-Type: text/html; charset=utf-8Vary: Accept-EncodingX-Runtime: 54ETag: "e7de821dc44f56a2c909a831a3427265"Content-Length: 19810Date: Sat, 18 Oct 2014 01:38:57 GMTServer: ITeye SERVER