ios - tutorial - cómo acercar o alejar en uipageviewcontroller?

uiscrollview autolayout

Question

Tengo un controlador de vista de página y configuro un controlador de vista hijo en uipageviewcontroller nombrado como contentviewcontroller.

thePageViewController = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStylePageCurl navigationOrientation: UIPageViewControllerNavigationOrientationHorizontal options:nil];

    thePageViewController.delegate = self;
    thePageViewController.dataSource = self;

    thePageViewController.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;

    contentViewController = [[HBDocumentChildViewController alloc] initWithPDF:PDFDocument];
    contentViewController.page = [modelArray objectAtIndex:0];
    NSArray *viewControllers = [NSArray arrayWithObject:contentViewController];
    [thePageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil];

    [self addChildViewController:thePageViewController];
    [self.view addSubview:thePageViewController.view];
    thePageViewController.view.frame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height);
    [thePageViewController didMoveToParentViewController:self];
    self.view.gestureRecognizers = thePageViewController.gestureRecognizers;
    self.view.backgroundColor = [UIColor underPageBackgroundColor];

Había hecho para cargar archivos PDF en páginas en el controlador de vista de página con la ayuda de una clase de vista de desplazamiento (pdfScrollView). El followig es la clase de contenido de uipageviewcontroller y la inicialización de la clase uiscrollview.

#import "HBDocumentChildViewController.h"

@interface HBDocumentChildViewController ()<UIWebViewDelegate>
{
    int currentPage;
    NSString*localPath;
}

@end

@implementation HBDocumentChildViewController

#pragma mark - View lifecycle

- (void)viewDidLoad
{
    [super viewDidLoad];

    // Create our PDFScrollView and add it to the view controller.
    CGPDFPageRef PDFPage = CGPDFDocumentGetPage(thePDF, [_page intValue]);
    pdfScrollView = [[PDFScrollView alloc] initWithFrame:self.view.frame];
    [pdfScrollView setPDFPage:PDFPage];
    [self.view addSubview:pdfScrollView];
    self.view.backgroundColor = [UIColor whiteColor];
    self.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
    pdfScrollView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
}

La siguiente es la clase uiscrollview,

/*
     File: PDFScrollView.m
 Abstract: UIScrollView subclass that handles the user input to zoom the PDF page.  This class handles swapping the TiledPDFViews when the zoom level changes.
  Version: 2


 */

#import "PDFScrollView.h"
#import "TiledPDFView.h"
#import <QuartzCore/QuartzCore.h>


@interface PDFScrollView ()

// A low resolution image of the PDF page that is displayed until the TiledPDFView renders its content.
@property (nonatomic, weak) UIImageView *backgroundImageView;

// The TiledPDFView that is currently front most.
@property (nonatomic, weak) TiledPDFView *tiledPDFView;

// The old TiledPDFView that we draw on top of when the zooming stops.
@property (nonatomic, weak) TiledPDFView *oldTiledPDFView;

@end



@implementation PDFScrollView
{
    CGPDFPageRef _PDFPage;

    // Current PDF zoom scale.
    CGFloat _PDFScale;
    CGFloat _PDFScaleH;
}


@synthesize backgroundImageView=_backgroundImageView, tiledPDFView=_tiledPDFView, oldTiledPDFView=_oldTiledPDFView;


- (id)initWithCoder:(NSCoder *)coder
{
    self = [super initWithCoder:coder];
    if (self) {
        self.decelerationRate = UIScrollViewDecelerationRateFast;
        self.delegate = self;
    }
    return self;
}


- (void)setPDFPage:(CGPDFPageRef)PDFPage;
{
    CGPDFPageRetain(PDFPage);
    CGPDFPageRelease(_PDFPage);
    _PDFPage = PDFPage;

    // Determine the size of the PDF page.
    CGRect pageRect = CGPDFPageGetBoxRect(_PDFPage, kCGPDFMediaBox);
    float actualHeight = pageRect.size.height;
    float actualWidth = pageRect.size.width;
    float imgRatio = actualWidth/actualHeight;
    float maxRatio = 768.0/911.0;

    if(imgRatio!=maxRatio){
        if(imgRatio < maxRatio){
            imgRatio = 911.0 / actualHeight;
            actualWidth = imgRatio * actualWidth;
            actualHeight = 911.0;
        }
        else{
            imgRatio = 768.0 / actualWidth;
            actualHeight = imgRatio * actualHeight;
            actualWidth = 768.0;
        }
    }
    pageRect.size = CGSizeMake(actualWidth, actualHeight);
    UIGraphicsBeginImageContext(pageRect.size);

    /*
     Create a low resolution image representation of the PDF page to display before the TiledPDFView renders its content.
     */
    UIGraphicsBeginImageContext(pageRect.size);

    CGContextRef context = UIGraphicsGetCurrentContext();

    // First fill the background with white.
    CGContextSetRGBFillColor(context, 1.0,1.0,1.0,1.0);
    CGContextFillRect(context,pageRect);

    CGContextSaveGState(context);
    // Flip the context so that the PDF page is rendered right side up.
    CGContextTranslateCTM(context, 0.0, pageRect.size.height);
    CGContextScaleCTM(context, 1.0, -1.0);

    // Scale the context so that the PDF page is rendered at the correct size for the zoom level.
    CGContextScaleCTM(context, imgRatio,imgRatio);
    CGContextDrawPDFPage(context, _PDFPage);
    CGContextRestoreGState(context);

    UIImage *backgroundImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();


    if (self.backgroundImageView != nil) {
        [self.backgroundImageView removeFromSuperview];
    }

    UIImageView *backgroundImageView = [[UIImageView alloc] initWithImage:backgroundImage];
    backgroundImageView.frame = pageRect;
    backgroundImageView.contentMode = UIViewContentModeScaleAspectFit;
    [self addSubview:backgroundImageView];
    [self sendSubviewToBack:backgroundImageView];
    self.backgroundImageView = backgroundImageView;

    // Create the TiledPDFView based on the size of the PDF page and scale it to fit the view.
    TiledPDFView *tiledPDFView = [[TiledPDFView alloc] initWithFrame:pageRect scale:imgRatio];
    [tiledPDFView setPage:_PDFPage];

    [self addSubview:tiledPDFView];
    self.tiledPDFView = tiledPDFView;
}


- (void)dealloc
{
    // Clean up.
    CGPDFPageRelease(_PDFPage);
}


#pragma mark -
#pragma mark Override layoutSubviews to center content

// Use layoutSubviews to center the PDF page in the view.
- (void)layoutSubviews 
{
    [super layoutSubviews];

    // Center the image as it becomes smaller than the size of the screen.

    CGSize boundsSize = self.bounds.size;
    CGRect frameToCenter = self.tiledPDFView.frame;

    // Center horizontally.

    if (frameToCenter.size.width < boundsSize.width)
        frameToCenter.origin.x = (boundsSize.width - frameToCenter.size.width) / 2;
    else
        frameToCenter.origin.x = 0;

    // Center vertically.

    if (frameToCenter.size.height < boundsSize.height)
        frameToCenter.origin.y = (boundsSize.height - frameToCenter.size.height) / 2;
    else
        frameToCenter.origin.y = 0;

    self.tiledPDFView.frame = frameToCenter;
    self.backgroundImageView.frame = frameToCenter;

    /*
     To handle the interaction between CATiledLayer and high resolution screens, set the tiling view''s contentScaleFactor to 1.0.
     If this step were omitted, the content scale factor would be 2.0 on high resolution screens, which would cause the CATiledLayer to ask for tiles of the wrong scale.
     */
    self.tiledPDFView.contentScaleFactor = 1.0;
}


#pragma mark -
#pragma mark UIScrollView delegate methods

/*
 A UIScrollView delegate callback, called when the user starts zooming.
 Return the current TiledPDFView.
 */
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
    return self.tiledPDFView;
}

/*
 A UIScrollView delegate callback, called when the user begins zooming.
 When the user begins zooming, remove the old TiledPDFView and set the current TiledPDFView to be the old view so we can create a new TiledPDFView when the zooming ends.
 */
- (void)scrollViewWillBeginZooming:(UIScrollView *)scrollView withView:(UIView *)view
{
    // Remove back tiled view.
    [self.oldTiledPDFView removeFromSuperview];

    // Set the current TiledPDFView to be the old view.
    self.oldTiledPDFView = self.tiledPDFView;
    [self addSubview:self.oldTiledPDFView];
}


/*
 A UIScrollView delegate callback, called when the user stops zooming.
 When the user stops zooming, create a new TiledPDFView based on the new zoom level and draw it on top of the old TiledPDFView.
 */
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale
{
    // Set the new scale factor for the TiledPDFView.
    _PDFScale *= scale;
    // Calculate the new frame for the new TiledPDFView.
    CGRect pageRect = CGPDFPageGetBoxRect(_PDFPage, kCGPDFMediaBox);
    pageRect.size = CGSizeMake(pageRect.size.width*_PDFScale, pageRect.size.height*_PDFScale);

    // Create a new TiledPDFView based on new frame and scaling.
    TiledPDFView *tiledPDFView = [[TiledPDFView alloc] initWithFrame:pageRect scale:_PDFScale];
    [tiledPDFView setPage:_PDFPage];

    // Add the new TiledPDFView to the PDFScrollView.
    [self addSubview:tiledPDFView];
    self.tiledPDFView = tiledPDFView;
}


@end

La representación de la página funciona correctamente, pero no obtuve el acercamiento / alejamiento en la vista que se muestra en la página. El método de delegado uiscrollview no funciona en el controlador de visualización de uipage. Por favor, ayúdame a encontrar la solución a este problema.

Answer 1

He realizado el desplazamiento y el zoom en el controlador de visualización de páginas. Cambié el método anterior UIPinchGestureRecognizer para acercar y alejar al tamaño actual de la página.

-(void)pinchDetected:(UIPinchGestureRecognizer *)pinchRecognizer

{   
    if([pinchRecognizer state] == UIGestureRecognizerStateBegan) {
        // Reset the last scale, necessary if there are multiple objects with different scales
        lastScale = [pinchRecognizer scale];
    }

    if ([pinchRecognizer state] == UIGestureRecognizerStateBegan ||[pinchRecognizer state] == UIGestureRecognizerStateChanged)
    {
        CGFloat currentScale = [[[pinchRecognizer view].layer valueForKeyPath:@"transform.scale"] floatValue];
        // Constants to adjust the max/min values of zoom
        const CGFloat maxScale = 1.5;
        const CGFloat minScale = 1.0;

        CGFloat newScale = 1 -  (lastScale - [pinchRecognizer scale]);
        newScale = MIN(newScale, maxScale / currentScale);
        newScale = MAX(newScale, minScale / currentScale);
        thePageViewController.view.transform = CGAffineTransformScale(thePageViewController.view.transform, newScale, newScale);
        lastScale = [pinchRecognizer scale];  // Store the previous scale factor for the next pinch gesture call
    }
}

Luego, agregué el código [pdfScrollView setScrollEnabled: YES];, [pdfScrollView setContentSize: CGSizeMake (768, 1100)]; en viewDidLoad del contenido viewcontroller (HBDocumentChildViewController) para desplazar la vista de contenido en la clase uipageviewcontroller.

 - (void)viewDidLoad
    {
        [super viewDidLoad];

        // Create our PDFScrollView and add it to the view controller.
        CGPDFPageRef PDFPage = CGPDFDocumentGetPage(thePDF, [_page intValue]);
        pdfScrollView = [[PDFScrollView alloc] initWithFrame:self.view.frame];
         pdfScrollView.bouncesZoom = YES;
        [pdfScrollView setScrollEnabled:YES];
        [pdfScrollView setContentSize:CGSizeMake(768, 1100)];
        [pdfScrollView setPDFPage:PDFPage];
        [self.view addSubview:pdfScrollView];
        self.view.backgroundColor = [UIColor whiteColor];
        self.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
        pdfScrollView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
        pdfScrollView.delegate = pdfScrollView;

    }

Pruebe este código para ampliar y reducir el tamaño de la página actual y desplazarse por el contenido del controlador de visualización de páginas.

Answer 2

Prueba esto

UIPinchGestureRecognizer *pinchRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchDetected:)];
[thePageViewController addGestureRecognizer:pinchRecognizer];
pinchRecognizer.delegate=self;

El método es

-(void)pinchDetected:(UIPinchGestureRecognizer *)pinchRecognizer
{
    CGFloat scale = pinchRecognizer.scale;
    thePageViewController.transform = CGAffineTransformScale(thePageViewController.transform, scale, scale);
    pinchRecognizer.scale = 1.0;
}