Button b =newButton();

b.setOnTouchListener(newView.OnTouchListener() {

intlastX,lastY;

@Override

public booleanonTouch(View v,MotionEvent event) {

//TODO Auto-generated method stub

intea = event.getAction();

Log.i("TAG","Touch:"+ ea);

switch(ea) {

caseMotionEvent.ACTION_DOWN:

lastX= (int) event.getRawX();

lastY= (int) event.getRawY();

break;

/**

* layout(l,t,r,b)

* l  Left position, relative to parent

t  Top position, relative to parent

r  Right position, relative to parent

b  Bottom position, relative to parent

* */

caseMotionEvent.ACTION_MOVE:

intdx = (int) event.getRawX() -lastX;

intdy = (int) event.getRawY() -lastY;

intleft = v.getLeft() + dx;

inttop = v.getTop() + dy;

intright = v.getRight() + dx;

intbottom = v.getBottom() + dy;

if(left <0) {

left =0;

right = left + v.getWidth();

}

if(right > screenWidth) {

right = screenWidth;

left = right - v.getWidth();

}

if(top <0) {

top =0;

bottom = top + v.getHeight();

}

if(bottom > screenHeight) {

bottom = screenHeight;

top = bottom - v.getHeight();

}

v.layout(left,top,right,bottom);

Log.i("","position："+ left +", "+ top +", "+ right +", "+ bottom);

lastX= (int) event.getRawX();

lastY= (int) event.getRawY();

break;

caseMotionEvent.ACTION_UP:

break;

}

return false;

}