iOS-UIScrollView puede desplazarse pero no puede hacer zoom

objective-c

Question

Quiero acercar / alejar UIScrollView que contiene un UIImageView . Con mi código a continuación, solo puedo desplazar el contenido de la vista de desplazamiento pero no puedo acercarlo.

La jerarquía de mi vista se ve así:

- (UIView *) containerView
-- (UIView *) contentView
--- (UIScrollView *) scrollView
---- (UIImageView *) self.imageView

Código:

UIView *previousContentView = nil;
for (NSInteger i = 0; i < 2; i++) {
contentView = [self addRandomColoredView];
[containerView addSubview:contentView];
[containerView.topAnchor constraintEqualToAnchor:contentView.topAnchor].active = true;
[containerView.bottomAnchor constraintEqualToAnchor:contentView.bottomAnchor].active = true;
scrollView = [self addRandomScrollView];
[contentView addSubview:scrollView];
self.imageView = [[UIImageView alloc] init];
[self.imageView setImage:[imagesArray objectAtIndex:i]];
[self.imageView setTranslatesAutoresizingMaskIntoConstraints:false];
[scrollView addSubview:self.imageView];
if (previousContentView) {
[VerticalSeparatorView addSeparatorBetweenView:previousContentView secondView:contentView];
NSLayoutConstraint *width = [contentView.widthAnchor constraintEqualToAnchor:previousContentView.widthAnchor];
width.priority = 250;
width.active = true;
} else {
[containerView.leadingAnchor constraintEqualToAnchor:contentView.leadingAnchor].active = true;
}
[contentView.topAnchor constraintEqualToAnchor:scrollView.topAnchor].active = true;
[contentView.bottomAnchor constraintEqualToAnchor:scrollView.bottomAnchor].active = true;
[contentView.leadingAnchor constraintEqualToAnchor:scrollView.leadingAnchor].active = true;
[contentView.trailingAnchor constraintEqualToAnchor:scrollView.trailingAnchor].active = true;
[scrollView.topAnchor constraintEqualToAnchor:self.imageView.topAnchor].active = true;
[scrollView.bottomAnchor constraintEqualToAnchor:self.imageView.bottomAnchor].active = true;
[scrollView.leadingAnchor constraintEqualToAnchor:self.imageView.leadingAnchor].active = true;
[scrollView.trailingAnchor constraintEqualToAnchor:self.imageView.trailingAnchor].active = true;
previousContentView = contentView;
}
[containerView.trailingAnchor constraintEqualToAnchor:previousContentView.trailingAnchor].active = true;
- (UIView *)addRandomColoredView
{
UIView *someView = [[UIView alloc] init];
someView.translatesAutoresizingMaskIntoConstraints = false;
[someView setBackgroundColor:[UIColor blackColor]];
return someView;
}
-(UIScrollView *)addRandomScrollView
{
UIScrollView *scrollView = [[UIScrollView alloc] init];
[scrollView setDelegate:self];
[scrollView setTranslatesAutoresizingMaskIntoConstraints:false];
[scrollView setBackgroundColor:[UIColor colorWithRed:arc4random_uniform(256)/255.0 green:arc4random_uniform(256)/255.0 blue:arc4random_uniform(256)/255.0 alpha:1.0]];
[scrollView setMaximumZoomScale:2.5f];
[scrollView setMinimumZoomScale:0.5f];
[scrollView setZoomScale:scrollView.minimumZoomScale];
return scrollView;
}
#pragma mark - UIScrollViewDelegate
-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
return self.imageView;
}

Creo que scrollView obtiene su tamaño de contentSize porque muestra la imagen y puedo desplazarme. ¿Por qué no puedo acercar o alejar?

Answer 1

Pruebe MWPhotoBrowser. Ha incorporado funciones de desplazamiento y zoom. Obtendrás más de lo que necesitas Buena suerte.

Answer 2

viewForZoomingInScrollView especificar un delegado para su vista de desplazamiento, y luego implementar viewForZoomingInScrollView para decirle que viewForZoomingInScrollView la vista de la imagen:

- (UIView *)addScrollViewWithImageView {
UIScrollView *scrollView = [[UIScrollView alloc] init];
scrollView.translatesAutoresizingMaskIntoConstraints = false;
scrollView.maximumZoomScale = 200.0;
scrollView.minimumZoomScale = 0.1;
scrollView.delegate = self;
UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"test.png"]];
imageView.translatesAutoresizingMaskIntoConstraints = false;
[self.view addSubview:scrollView];
[scrollView addSubview:imageView];
[NSLayoutConstraint activateConstraints:@[
[imageView.topAnchor constraintEqualToAnchor:scrollView.topAnchor],
[imageView.leftAnchor constraintEqualToAnchor:scrollView.leftAnchor],
[imageView.rightAnchor constraintEqualToAnchor:scrollView.rightAnchor],
[imageView.bottomAnchor constraintEqualToAnchor:scrollView.bottomAnchor]
]];
return scrollView;
}
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
return scrollView.subviews.firstObject;
}

Y luego para poblar estas vistas de desplazamiento con zoom con vistas de imagen, su viewDidLoad podría verse así:

- (void)viewDidLoad {
[super viewDidLoad];
UIView *previousContentView = nil;
for (NSInteger i = 0; i < 3; i++) {
UIView *contentView = [self addScrollViewWithImageView];
[self.view.leadingAnchor constraintEqualToAnchor:contentView.leadingAnchor].active = true;
[self.view.trailingAnchor constraintEqualToAnchor:contentView.trailingAnchor].active = true;
if (previousContentView) {
[HorizontalSeparatorView addSeparatorBetweenView:previousContentView secondView:contentView];
NSLayoutConstraint *height = [contentView.heightAnchor constraintEqualToAnchor:previousContentView.heightAnchor];
height.priority = 250;
height.active = true;
} else {
[self.view.topAnchor constraintEqualToAnchor:contentView.topAnchor].active = true;
}
previousContentView = contentView;
}
[self.view.bottomAnchor constraintEqualToAnchor:previousContentView.bottomAnchor].active = true;
}