双击以使用UIScrollView进行缩放

Question

我正在使用Apple的源代码。我确信只有一个我搞砸了的片段。我有一个以编程方式制作的表单。当我双击识别器触发并通过动作但我实际上不会变焦。有什么建议？谢谢你的帮助

imageScrollView.delegate=self;

CGRect fullScreenRect=[[UIScreen mainScreen] applicationFrame];
imageScrollView=[[UIScrollView alloc]initWithFrame:fullScreenRect];
imageScrollView.contentSize=CGSizeMake(750,1250);
imageScrollView.minimumZoomScale=1.0;
imageScrollView.maximumZoomScale=5.0;
[imageScrollView setZoomScale:imageScrollView.minimumZoomScale];
self.view=imageScrollView;
[imageScrollView release];

在scrollview中添加了一堆UItextfields / labels。     aircraftType = [[UITextField alloc] initWithFrame：CGRectMake（170,32,150,15）];     aircraftType.font = [UIFont systemFontOfSize：10];     aircraftType.borderStyle = UITextBorderStyleRoundedRect;     aircraftType.placeholder = @“Aicraft Type”;     aircraftType.delegate = self;     [self.view addSubview：aircraftType];

#pragma mark UIScrollViewDelegate methods
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
    return [imageScrollView viewWithTag:ZOOM_VIEW_TAG];
}

#pragma mark TapDetectingImageViewDelegate methods
- (void)handleDoubleTap:(UIGestureRecognizer *)gestureRecognizer {
    // double tap zooms in

    float newScale = [imageScrollView zoomScale] * ZOOM_STEP;
    CGRect zoomRect = [self zoomRectForScale:newScale withCenter:[gestureRecognizer locationInView:gestureRecognizer.view]];
    [imageScrollView zoomToRect:zoomRect animated:YES];

}


#pragma mark Utility methods
- (CGRect)zoomRectForScale:(float)scale withCenter:(CGPoint)center {

    CGRect zoomRect;

    // the zoom rect is in the content view's coordinates.
    //    At a zoom scale of 1.0, it would be the size of the imageScrollView's bounds.
    //    As the zoom scale decreases, so more content is visible, the size of the rect grows.
    zoomRect.size.height = [imageScrollView frame].size.height / scale;
    zoomRect.size.width  = [imageScrollView frame].size.width  / scale;

    // choose an origin so as to get the right center.
    zoomRect.origin.x    = center.x - (zoomRect.size.width  / 2.0);
    zoomRect.origin.y    = center.y - (zoomRect.size.height / 2.0);



    return zoomRect;
}