我正在尝试使用启用了分页的UIScrollView。我将各种UIView添加到UISCrollView作为子视图。我希望那些子视图小于滚动视图的大小,所以我相应地修改了我的约束。现在,当我实际上向左/向右滑动它们时,不要碰巧在中心。我期待它显示上一页/下一页的视图从侧面偷看,当前页面位于中心。
下面是我的代码scrollview实现
//
// ViewController.m
// Paging
//
#import "ViewController.h"
@interface ViewController ()
@property (nonatomic, strong) UIScrollView *pagingScrollView;
@end
@implementation ViewController
- (UIScrollView *)pagingScrollView {
if (!_pagingScrollView) {
_pagingScrollView = [[UIScrollView alloc] initWithFrame:CGRectZero];
_pagingScrollView.translatesAutoresizingMaskIntoConstraints = NO;
_pagingScrollView.backgroundColor = [UIColor orangeColor];
_pagingScrollView.showsHorizontalScrollIndicator = NO;
_pagingScrollView.showsVerticalScrollIndicator = NO;
_pagingScrollView.contentInset = UIEdgeInsetsZero;
_pagingScrollView.pagingEnabled = YES;
_pagingScrollView.clipsToBounds = NO;
_pagingScrollView.bounces = NO;
}
return _pagingScrollView;
}
- (void)viewDidLoad {
[super viewDidLoad];
[self scrollViewSetUp];
NSDictionary *views = NSDictionaryOfVariableBindings(_pagingScrollView);
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[_pagingScrollView]|"
options:0
metrics:nil
views:views]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[_pagingScrollView]|"
options:0
metrics:nil
views:views]];
}
- (void)scrollViewSetUp {
[self.view addSubview:self.pagingScrollView];
UIView *lastView = nil;
NSInteger arrayCount = 5;
for(NSInteger index = 0; index < arrayCount; index++)
{
UIView *view = [[UIView alloc] initWithFrame:CGRectZero];
view.translatesAutoresizingMaskIntoConstraints = NO;
view.backgroundColor = [UIColor yellowColor];
[self.pagingScrollView addSubview:view];
[self.pagingScrollView addConstraint:[NSLayoutConstraint constraintWithItem:view
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:self.pagingScrollView
attribute:NSLayoutAttributeTop
multiplier:1
constant:40]];
[self.pagingScrollView addConstraint:[NSLayoutConstraint constraintWithItem:view
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:self.pagingScrollView
attribute:NSLayoutAttributeHeight
multiplier:0.80
constant:0]];
[self.pagingScrollView addConstraint:[NSLayoutConstraint constraintWithItem:view
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:self.pagingScrollView
attribute:NSLayoutAttributeWidth
multiplier:0.80
constant:0]];
if (lastView == nil && index == 0){
[self.pagingScrollView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-20-[view(==_pagingScrollView)]"
options:0
metrics:nil
views:@{@"view":view, @"_pagingScrollView":_pagingScrollView}]];
} else {
[self.pagingScrollView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:[lastView]-20-[view]"
options:0
metrics:nil
views:@{@"lastView":lastView, @"view":view, @"_pagingScrollView":_pagingScrollView}]];
}
if(index == arrayCount-1) {
[self.pagingScrollView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:[view]-20-|"
options:0
metrics:nil
views:@{@"view":view}]];
}
lastView = view;
}
}
@end
任何指针/评论/反馈都非常感谢。感谢。
答案 0 :(得分:1)
//
// ViewController.h
// Test
//
// Created by Lee on 7/8/16.
// Copyright © 2016 Lee. All rights reserved.
//
#import <UIKit/UIKit.h>
@interface ViewController : UIViewController
@property (nonatomic, strong) UIScrollView *pagingScrollView;
@end
//
// ViewController.m
// Test
//
// Created by Lee on 7/8/16.
// Copyright © 2016 Lee. All rights reserved.
//
#import "ViewController.h"
@interface ViewController ()<UIScrollViewDelegate>
@property (nonatomic,strong)NSMutableArray *subviewsCenterArray;
@end
@implementation ViewController
- (UIScrollView *)pagingScrollView {
if (!_pagingScrollView) {
_pagingScrollView = [[UIScrollView alloc] initWithFrame:CGRectZero];
_pagingScrollView.translatesAutoresizingMaskIntoConstraints = NO;
_pagingScrollView.backgroundColor = [UIColor orangeColor];
_pagingScrollView.showsHorizontalScrollIndicator = NO;
_pagingScrollView.showsVerticalScrollIndicator = NO;
_pagingScrollView.contentInset = UIEdgeInsetsZero;
_pagingScrollView.pagingEnabled = NO;
_pagingScrollView.clipsToBounds = NO;
_pagingScrollView.bounces = NO;
_pagingScrollView.delegate = self;
}
return _pagingScrollView;
}
- (void)viewDidLoad {
[super viewDidLoad];
[self scrollViewSetUp];
NSDictionary *views = NSDictionaryOfVariableBindings(_pagingScrollView);
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[_pagingScrollView]|"
options:0
metrics:nil
views:views]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[_pagingScrollView]|"
options:0
metrics:nil
views:views]];
}
- (void)scrollViewSetUp {
[self.view addSubview:self.pagingScrollView];
UIView *lastView = nil;
NSInteger arrayCount = 5;
_subviewsCenterArray = [NSMutableArray array];
for(NSInteger index = 0; index < arrayCount; index++)
{
UIView *view = [[UIView alloc] initWithFrame:CGRectZero];
view.translatesAutoresizingMaskIntoConstraints = NO;
view.backgroundColor = [UIColor colorWithRed:arc4random()%255/255.0 green:arc4random()%255/255.0 blue:arc4random()%255/255.0 alpha:1];
view.tag = 9999;
view.layer.cornerRadius = 6;
[self.pagingScrollView addSubview:view];
[self.pagingScrollView addConstraint:[NSLayoutConstraint constraintWithItem:view
attribute:NSLayoutAttributeTop
relatedBy:NSLayoutRelationEqual
toItem:self.pagingScrollView
attribute:NSLayoutAttributeTop
multiplier:1
constant:40]];
[self.pagingScrollView addConstraint:[NSLayoutConstraint constraintWithItem:view
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:self.pagingScrollView
attribute:NSLayoutAttributeHeight
multiplier:0.80
constant:0]];
[self.pagingScrollView addConstraint:[NSLayoutConstraint constraintWithItem:view
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:self.pagingScrollView
attribute:NSLayoutAttributeWidth
multiplier:0.80
constant:0]];
if (lastView == nil && index == 0){
[self.pagingScrollView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-20-[view(==_pagingScrollView)]"
options:0
metrics:nil
views:@{@"view":view, @"_pagingScrollView":_pagingScrollView}]];
} else {
[self.pagingScrollView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:[lastView]-20-[view]"
options:0
metrics:nil
views:@{@"lastView":lastView, @"view":view, @"_pagingScrollView":_pagingScrollView}]];
}
if(index == arrayCount-1) {
[self.pagingScrollView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:[view]-20-|"
options:0
metrics:nil
views:@{@"view":view}]];
}
[self.view layoutIfNeeded];
lastView = view;
}
}
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{
[self changeTheCardStatus:scrollView];
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
[self changeTheCardStatus:scrollView];
}
-(void)changeTheCardStatus:(UIScrollView *)scrollView{
for (UIView *view in scrollView.subviews) {
if (view.tag == 9999) {
[_subviewsCenterArray addObject:@(view.center.x)];
}
}
CGFloat currentCenterOffsetX = scrollView.contentOffset.x + CGRectGetWidth(self.view.frame)/2.0;
NSMutableArray *absoluteValueArray = [NSMutableArray array];
NSMutableDictionary *absoluteValueDictionary = [NSMutableDictionary dictionary];
for (int i = 0; i < _subviewsCenterArray.count; i ++) {
float subviewsCenterPointX = [_subviewsCenterArray[i] floatValue];
double absolute = fabs(subviewsCenterPointX - currentCenterOffsetX);
[absoluteValueArray addObject:@(absolute)];
[absoluteValueDictionary setValue:@(subviewsCenterPointX) forKey:[NSString stringWithFormat:@"%f",absolute]];
}
[absoluteValueArray sortUsingComparator:^NSComparisonResult(id _Nonnull obj1, id _Nonnull obj2) {
double a = [obj1 doubleValue];
double b = [obj2 doubleValue];
if (a>b) {
return NSOrderedDescending;
}
else if (a<b){
return NSOrderedAscending;
}
else{
return NSOrderedSame;
}
}];
double shortValue = [absoluteValueArray.firstObject doubleValue];
double centerX = [[absoluteValueDictionary objectForKey:[NSString stringWithFormat:@"%f",shortValue]] doubleValue];
[UIView animateWithDuration:0.25 animations:^{
scrollView.contentOffset = CGPointMake(centerX - CGRectGetWidth(self.view.frame)/2.0, 0);
}];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end
答案 1 :(得分:0)
当然不是。 pagingScrollView的子视图没有正确的宽度!这些子视图也没有正确的水平边距。
首先您应该更正您的设置宽度代码,将乘数更改为1并将常量更改为-40。像这样:
alt+shift+R
然后修改子视图边距,将-20更改为-40,就像这样
[self.pagingScrollView addConstraint:[NSLayoutConstraint constraintWithItem:view
attribute:NSLayoutAttributeWidth
relatedBy:NSLayoutRelationEqual
toItem:self.pagingScrollView
attribute:NSLayoutAttributeWidth
multiplier:1
constant:-40]];