实现IOS 7放大、缩小过渡

Question

我想在我的 ios 应用主屏幕中实现放大缩小过渡，就像 ios7 应用启动器中的过渡一样。

我不确定我是否走在正确的道路上，但我在主屏幕中创建了UIScrollView，并在滚动视图中创建了按钮。我将其中一个按钮的矩形框传递给zoomToRect，但没有进行缩放。

我的计划是切换到我的应用程序的另一个视图，以及填充屏幕的按钮上的放大动画。

我在使用UIScrollView 和zoomToRect 时遗漏了什么，或者我在主屏幕上使用滚动视图时完全错误。我可以通过使用UIView 作为我的应用程序的主屏幕，然后使用CGAffineTransformMakeScale 转换来实现放大效果。

Answer 1

1.在您的故事板上，将 uiscrollView 放在视图控制器上。 2.将uiimageView放在uiscrollView上 3.确保您的故事板不在自动布局上。 4.在你的显示尺寸检查器上，确保你的滚动视图和图像视图的高度和高度是相同的。 5.确保Autosize引脚都被点击。

转到分配给您正在处理的 ViewController 的 UIViewContoller 类。

在头文件中添加以下属性：

         #import <UIKit/UIKit.h>

        @interface ViewController : UIViewController <UIScrollViewDelegate>


        @property (nonatomic, strong) UIImageView* imageViewPointer;
//Make sure scrollView is linked to the ui element on your storyboard
        @property (strong, nonatomic) IBOutlet UIScrollView *scrollView;
//Make sure imageView is linked to the ui element on your storyboard
        @property (strong, nonatomic) IBOutlet UIImageView *imageView;

        // These properties are new
        @property (nonatomic, strong) NSMutableArray* imageViewConstraints;
        @property (nonatomic) BOOL imageViewConstraintsNeedUpdating;
        @property (nonatomic, strong) UIScrollView* scrollViewPointer;

    //Then in the implementation file this the following code to implement

    @interface ViewController ()

    @end

    @implementation ViewController

    @synthesize scrollView,imageView;

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



    - (void)scrollViewWillBeginZooming:(UIScrollView *)scrollView withView:(UIView *)view
    {
        if(_imageViewConstraintsNeedUpdating)
        {
            // Remove the previous image view constraints
            [self.view removeConstraints:_imageViewConstraints];

            // Replace them with new ones, this time constraining against the width & height of the scroll view's content, not the scroll view itself
            NSDictionary *viewsDictionary = NSDictionaryOfVariableBindings(_scrollViewPointer, _imageViewPointer);
            [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[_imageViewPointer(width)]|" options:0 metrics:@{@"width" : @(_scrollViewPointer.contentSize.width)} views:viewsDictionary]];
            [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[_imageViewPointer(height)]|" options:0 metrics:@{@"height" : @(_scrollViewPointer.contentSize.height)} views:viewsDictionary]];

            self.imageViewConstraintsNeedUpdating = NO;
        }
    }



    - (void)viewDidLoad
    {
        [super viewDidLoad];
        // Do any additional setup after loading the view.


        [imageView setImage:[UIImage imageNamed:@"Your Image"]];

        imageView.contentMode = UIViewContentModeScaleAspectFit;

       scrollView.contentInset = UIEdgeInsetsZero;

        self.imageViewPointer = imageView;

        // New
        self.scrollViewPointer = scrollView;
        scrollView.maximumZoomScale = 5;
        scrollView.minimumZoomScale = 1.0;
        scrollView.delegate = self;

        NSDictionary *viewsDictionary = NSDictionaryOfVariableBindings(scrollView, imageView);
        NSLog(@"Current views dictionary: %@", viewsDictionary);
        [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[scrollView]|" options:0 metrics: 0 views:viewsDictionary]];
        [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[scrollView]|" options:0 metrics: 0 views:viewsDictionary]];

        // Saving the image view width & height constraints
        self.imageViewConstraints = [[NSMutableArray alloc] init];
        // Constrain the image view to be the same width & height of the scroll view
        [_imageViewConstraints addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[imageView(scrollView)]|" options:0 metrics: 0 views:viewsDictionary]];
        [_imageViewConstraints addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[imageView(scrollView)]|" options:0 metrics: 0 views:viewsDictionary]];

        // Add the image view constraints to the VIEW, not the scroll view
        [self.view addConstraints:_imageViewConstraints];

        // Flag
        self.imageViewConstraintsNeedUpdating = YES;


    }

    @end