How to prevent UIView from being resized to fit Sc

2019-02-14 03:08发布

问题:

I'm writing a PDF reader using vfr-reader library. To display two pages in landscape i'm rendering each page into its own view, then add these two views to a container view, then add container view to a scroll view. Each view's autoresizingMask is set to UIViewAutoresizingNone, contentMode is UIViewContentModeRedraw, autoresizingSubviews is set to 'NO' for all views.

But still somehow container view is autoresized to fit scroll view's height, and I don't know where is this happening. I care about this because, when autoresizing container view, it's width becomes larger than screen width, and I cannot scroll to the next two pages with a single swipe (two swipes are needed), which sucks. What am I missing?

EDIT gonna add some come if it helps. In the ViewController I create a Scroll View with following options:

theScrollView = [[ReaderScrollView alloc] initWithFrame:viewRect];
theScrollView.scrollsToTop = NO;
theScrollView.pagingEnabled = YES;
theScrollView.delaysContentTouches = NO;
theScrollView.showsVerticalScrollIndicator = NO;
theScrollView.showsHorizontalScrollIndicator = NO;
theScrollView.contentMode = UIViewContentModeRedraw;
theScrollView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
theScrollView.backgroundColor = [UIColor clearColor];
theScrollView.userInteractionEnabled = YES;
theScrollView.autoresizesSubviews = NO;
theScrollView.delegate = self;
[self.view addSubview:theScrollView];

When I'm drawing pages I'm adding an UIView to the Scroll View, which is being initiated this way:

if ((self = [super initWithFrame:frame]))
{
    self.autoresizesSubviews = YES;
    self.userInteractionEnabled = YES;
    self.contentMode = UIViewContentModeRedraw;
    self.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;       
    self.backgroundColor = [UIColor clearColor];

    theScrollView = [[ReaderScrollView alloc] initWithFrame:self.bounds]; // Not sure about this part - why is the 2nd scroll view added?
// this is the way its done in vfr reader

    theScrollView.scrollsToTop = NO;
    theScrollView.delaysContentTouches = NO;
    theScrollView.showsVerticalScrollIndicator = NO;
    theScrollView.showsHorizontalScrollIndicator = NO;
    theScrollView.contentMode = UIViewContentModeRedraw;
    theScrollView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
    theScrollView.backgroundColor = [UIColor clearColor];
    theScrollView.userInteractionEnabled = YES;
    theScrollView.autoresizesSubviews = NO;
    theScrollView.bouncesZoom = YES;
    theScrollView.delegate = self;

    theContentView = [[ReaderContentPage alloc] initWithURL:fileURL page:page password:phrase landscape:(BOOL)isLandscape position:FALSE];
    CGRect viewRect = CGRectZero;
    viewRect.size.width = theContentView.bounds.size.width;
    viewRect.size.height = theContentView.bounds.size.height;    


    if( isLandscape){
        NSLog(@"Landscape detected in content view");
        if (theContentView == NULL)
        {
            theContentView = [[ReaderContentPage alloc] initWithURL:fileURL page:(page+1) password:phrase landscape:(BOOL)isLandscape position:FALSE];
            theContentView2 = NULL;
            viewRect.size.width = theContentView.bounds.size.width;
            viewRect.size.height = theContentView.bounds.size.height;    
        } else {
            if (page == 1)
                theContentView2 = NULL;
            else
                theContentView2 = [[ReaderContentPage alloc] initWithURL:fileURL page:(page+1) password:phrase landscape:(BOOL)isLandscape position:TRUE];
            if (theContentView2 != NULL)
               viewRect.size.width = theContentView.bounds.size.width*2;
        }            

    }       
    if (theContentView != nil) // Must have a valid and initialized content view
    {

        theContainerView = [[UIView alloc] initWithFrame:viewRect];


        theContainerView.autoresizesSubviews = NO;
        theContainerView.userInteractionEnabled = NO;
        theContainerView.contentMode = UIViewContentModeRedraw;            
        theContainerView.autoresizingMask = UIViewAutoresizingNone;
        theContainerView.backgroundColor = [UIColor whiteColor];


        theScrollView.contentSize = theContentView.bounds.size; // Content size same as view size


        theScrollView.contentOffset = CGPointMake((0.0f - CONTENT_INSET), (0.0f - CONTENT_INSET));
        theScrollView.contentInset = UIEdgeInsetsMake(CONTENT_INSET, CONTENT_INSET, CONTENT_INSET, CONTENT_INSET);

        theThumbView = [[ReaderContentThumb alloc] initWithFrame:theContentView.bounds]; // Page thumb view           

        [theContainerView addSubview:theThumbView]; // Add the thumb view to the container view

        [theContainerView addSubview:theContentView]; // Add the content view to the container view

        if(( isLandscape) && (theContentView2 != NULL)){            
             [theContainerView addSubview:theContentView2]; // Add the content view to the container view

        }           



        [theScrollView addSubview:theContainerView]; // Add the container view to the scroll view

        [self updateMinimumMaximumZoom]; // Update the minimum and maximum zoom scales

        theScrollView.zoomScale = theScrollView.minimumZoomScale; // Zoom to fit
    }

    [self addSubview:theScrollView]; // Add the scroll view to the parent container view   

    [theScrollView addObserver:self forKeyPath:@"frame" options:NSKeyValueObservingOptionNew context:NULL];

    self.tag = page; // Tag the view with the page number
}

return self;

And ReaderContentPage is created this way:

if ((self = [super initWithFrame:frame]))
    {
        self.autoresizesSubviews = NO;

        self.userInteractionEnabled = NO;
        self.clearsContextBeforeDrawing = NO;
        self.contentMode = UIViewContentModeRedraw;     
        self.autoresizingMask = UIViewAutoresizingNone;
        self.backgroundColor = [UIColor clearColor];

        view = self; // Return self
    }

回答1:

In the function updateMinimumMaximumZoom in the class ReaderContentView:

The calculation of the zoomscale to fit the screen is done with single view, but in landscape it should be calculated form theContainerView.

Try replacing this code

CGFloat zoomScale = ZoomScaleThatFits(targetRect.size, theContentView.bounds.size);

with

CGFloat zoomScale = ZoomScaleThatFits(targetRect.size, theContainerView.bounds.size);



回答2:

There is a contentMode property in UIScrollView, change it to UIViewContentModeCenter or something else to prevent resizing.



标签: ios xcode uiview