iphone - how to make an ImageView zoomable with or without ScrollView.? -

i have uimageview in ib , added map image on uimageview. want make image pinch zoomable.

here code:

- (void)viewdidload {    [super viewdidload];     self.title = @"map";     self.mapimageview.contentmode = uiviewcontentmodescaleaspectfit;    [self.mapscrollview addsubview:self.mapimageview];    [self.mapscrollview setcontentsize:cgsizemake(self.mapimageview.frame.size.width, self.mapimageview.frame.size.height)];    [self.mapscrollview setminimumzoomscale:1.0];    [self.mapscrollview setmaximumzoomscale:4.0]; }  - (uiview *)viewforzoominginscrollview:(uiscrollview *)scrollview {    return self.mapimageview; } 

but doesn't help, can see uiscrollview coming nothing happen image.
in advance.

try this

    //at viewdidload (or whare create mapimageview)    uipinchgesturerecognizer *pinchrecognizer = [[uipinchgesturerecognizer alloc] initwithtarget:self action:@selector(scale:)];    [pinchrecognizer setdelegate:self];    [mapimageview addgesturerecognizer:pinchrecognizer];     mapimageview.userinteractionenabled=yes;        -(void)scale:(id)sender {        [yourview bringsubviewtofront:[(uipinchgesturerecognizer*)sender view]];         if([(uipinchgesturerecognizer*)sender state] == uigesturerecognizerstateended) {            lastscale = 1.0;  //global float variable.            return;        }         cgfloat scale = 1.0 - (lastscale - [(uipinchgesturerecognizer*)sender scale]);         cgaffinetransform currenttransform = [(uipinchgesturerecognizer*)sender view].transform;        cgaffinetransform newtransform = cgaffinetransformscale(currenttransform, scale, scale);         [[(uipinchgesturerecognizer*)sender view] settransform:newtransform];    }