UIPageControl

最新推荐文章于 2020-07-13 07:42:37 发布

原创最新推荐文章于 2020-07-13 07:42:37 发布 · 341 阅读

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本文介绍如何在 iOS 应用中实现带有分页指示器的图片轮播功能，并展示了如何通过 UIScrollView 控制图片缩放及页面切换。

准备工作不赘述

MainViewController.m

#import "MainViewController.h"
#import "LTView.h"
#define WIDTH self.view.frame.size.width
#define HEIGHT self.view.frame.size.height
@interface MainViewController ()<UIScrollViewDelegate>
@property(nonatomic,retain)UIScrollView *scrollView;
@end

@implementation MainViewController
-(void)dealloc
{
    [_scrollView release];
    [super dealloc];
}
- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    self.scrollView=[[UIScrollView alloc]initWithFrame:CGRectMake(0, 0, WIDTH, HEIGHT)];
    self.scrollView.backgroundColor=[UIColor yellowColor];
    [self.view addSubview:self.scrollView];
    [self.scrollView release];

    // 设置让scrollView滚动
    self.scrollView.contentSize=CGSizeMake(WIDTH * 4, HEIGHT);

    self.scrollView.pagingEnabled=YES;
    self.scrollView.bounces=NO;

    for (NSInteger i=1; i<5; i++) {
        NSString *picName=[NSString stringWithFormat:@"%ld.jpg",i];
        UIImageView *imageView=[[UIImageView alloc]initWithImage:[UIImage imageNamed:picName]];
        imageView.frame=CGRectMake(WIDTH * (i-1), 0, WIDTH, HEIGHT - 100);
        // 把imageView放到scrollView中
        [self.scrollView addSubview:imageView];
        [imageView release];

    }

    // scrollView的缩放
    // 缩放的比例
    // 最大
    self.scrollView.maximumZoomScale=2;    
    // 最小
    self.scrollView.minimumZoomScale=0.5;    
    // 原始的缩放比例
    self.scrollView.zoomScale=1;    

    self.scrollView.delegate=self;
     UIPageControl *pageControl=[[UIPageControl alloc]initWithFrame:CGRectMake(90, 600, 200, 40)];
    pageControl.backgroundColor=[UIColor redColor];
    [self.view addSubview:pageControl];
    [pageControl release];

    // 图片个数和点的个数相同
    pageControl.numberOfPages=4;
    // 点的背景颜色
    pageControl.pageIndicatorTintColor=[UIColor blueColor];
    // 被选中的点的颜色
    pageControl.currentPageIndicatorTintColor=[UIColor blackColor];

    // 给它添加一个点击方法
    [pageControl addTarget:self action:@selector(pageAction:) forControlEvents:UIControlEventValueChanged];

    pageControl.tag=1;

    LTView *view=[[LTView alloc]initWithFrame:CGRectMake(0, 100, 375, 30)];
    [self.view addSubview:view];
    view.label.text=@"用户名";
    view.textField.placeholder=@"请输入用户名";
    view.textField.keyboardType=UIReturnKeyDefault;
    [view release];      
}

#pragma mark  专门用来缩放的协议方法
-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
    return [scrollView.subviews firstObject];
}


-(void)pageAction:(UIPageControl *)pageControl
{
    NSLog(@"%ld",pageControl.currentPage);
    // 触发事件,进行图片的切换
    [self.scrollView setContentOffset:CGPointMake(pageControl.currentPage * WIDTH, 0)animated:YES];
}

-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    // 滑动图片,让圆点跟着一起动
    UIPageControl *pageControl=(UIPageControl *)[self.view viewWithTag:1];
    pageControl.currentPage=self.scrollView.contentOffset.x/WIDTH;

}