固定UIScrollView滑动的方向

一般而言,我们通过这两个参数CGRectMake以及contentSize就可以自动的让UIScrollView只往一个方向滚动.但我遇到过非常奇葩的情况,那就是即使设置的CGRectMake以及contentSize没有一点点问题,这个UIScrollView也能够上下左右滚动-_-!!.

为了不依赖于CGRectMake以及contentSize,我们可以通过在代理方法scrollViewDidScroll:中进行限制即可.

没有限制之前的效果:

源码:

//
//  RootViewController.m
//  BUG
//
//  Copyright (c) 2014年 Y.X. All rights reserved.
//

#import "RootViewController.h"

@interface RootViewController ()<UIScrollViewDelegate>

{
    UIScrollView    *_showView;
}

@end

@implementation RootViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    UIImageView *showImageView =         [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"长图.jpg"]];

    _showView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 50, 320, 100)];
    _showView.delegate = self;
    [_showView addSubview:showImageView];
    _showView.contentSize = showImageView.frame.size;
    [self.view addSubview:_showView];
}

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    CGPoint point = scrollView.contentOffset;
//    point.y = 0.f;
    scrollView.contentOffset = point;
}

@end

限制后效果:

//
//  RootViewController.m
//  BUG
//
//  Copyright (c) 2014年 Y.X. All rights reserved.
//

#import "RootViewController.h"

@interface RootViewController ()<UIScrollViewDelegate>

{
    UIScrollView    *_showView;
}

@end

@implementation RootViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    UIImageView *showImageView =         [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"长图.jpg"]];

    _showView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 50, 320, 100)];
    _showView.delegate = self;
    [_showView addSubview:showImageView];
    _showView.contentSize = showImageView.frame.size;
    [self.view addSubview:_showView];
}

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    CGPoint point = scrollView.contentOffset;

    // 限制y轴不动
    point.y = 0.f;

    scrollView.contentOffset = point;
}

@end

核心代码:

固定UIScrollView滑动的方向