問題描述

我的 IB 中有一個(gè) UImageView，并在該 UImageView 上添加了一個(gè)地圖圖像.我想讓該圖像可以縮放.

I have an UImageView in my IB and added a map image on that UImageView. I want to make that image pinch zoomable.

這是我的代碼:

- (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;
}

但這無濟(jì)于事，我可以看到 UIScrollView 來了，但我的圖像沒有任何反應(yīng).
提前致謝.

but this doesn't help, I can see a UIScrollView Coming but nothing happen to my image.
Thanks in advance.

推薦答案

在你的 ViewController.h 文件中添加 UIScrollViewDelegate

Add UIScrollViewDelegate in your ViewController.h file

然后將以下代碼添加到您的 ViewController.m 文件中

then add following code to your ViewController.m file

如果您使用此代碼，則無需添加 UIPinchGestureRecognizer

No need to add UIPinchGestureRecognizer if your using this code

    - (void)scrollViewDidZoom:(UIScrollView *)scrollView
    {

    UIView* zoomView = [scrollView.delegate viewForZoomingInScrollView:scrollView];

    CGRect zoomViewFrame = zoomView.frame;

    if(zoomViewFrame.size.width < scrollView.bounds.size.width)

    {

    zoomViewFrame.origin.x = (scrollView.bounds.size.width - zoomViewFrame.size.width) / 2.0;

    }

    else

    {
    zoomViewFrame.origin.x = 0.0;
    }

    if(zoomViewFrame.size.height < scrollView.bounds.size.height)

     {      zoomViewFrame.origin.y = (scrollView.bounds.size.height - zoomViewFrame.size.height) / 2.0;

    }
    else

    {
    zoomViewFrame.origin.y = 0.0;
    }
    zoomView.frame = zoomViewFrame;
    }

修改viewDidLoad如下

- (void)viewDidLoad
 {
     [super viewDidLoad];
    self.mapScrollView.delegate = self;
    self.mapScrollView.minimumZoomScale = 1.0;
    self.mapScrollView.maximumZoomScale = 4.0;
    UIImage * myImage= [UIImage imageNamed:@"Background.png"]; //add your image here
    [self.mapImageView setImage:myImage];
    [self.mapImageView sizeToFit];
    self.mapScrollView.contentSize = myImage.size;

}

在此處指定要放大的imageView

Specify the imageView to zoom here

- (UIView*)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
    return self.mapImageView;
}

要避免 UIScrollView 在 zoomimg 上的奇怪行為，請(qǐng)使用此方法

To avoid the strange behaviour of UIScrollView on zoomimg use this method

- (void)view:(UIView*)view setCenter:(CGPoint)centerPoint
{
    CGRect viewFrame = view.frame;
        CGPoint contentOffset = self.mapScrollView.contentOffset;

        CGFloat x = centerPoint.x - viewFrame .size.width / 2.0;
        CGFloat y = centerPoint.y - viewFrame .size.height / 2.0;

    if(x < 0)
    {
        contentOffset.x = -x;
        viewFrame .origin.x = 0.0;
    }
    else
    {
        viewFrame .origin.x = x;
    }
    if(y < 0)
    {
        contentOffset.y = -y;
        viewFrame .origin.y = 0.0;
    }
    else
    {
        viewFrame .origin.y = y;
    }

    view.frame = viewFrame ;
    self.mapScrollView.contentOffset = contentOffset;
}

然后在viewDidAppear上調(diào)用上面的方法

Then call the above method on viewDidAppear

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
    CGPoint centerPoint = CGPointMake(CGRectGetMidX(self.mapScrollView.bounds),
                                  CGRectGetMidY(self.mapScrollView.bounds));
    [self view:self.mapImageView setCenter:centerPoint];
}

看看這個(gè) 鏈接.我從那個(gè)鏈接學(xué)到了這項(xiàng)技術(shù).

have a look at this link if you need more clarification. I learned this technique from that link.

這篇關(guān)于如何使用或不使用 ScrollView 使 ImageView 可縮放?的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！