iOS开发UI篇—用纯代码写实现图片轮播

一、实现效果

实现图片的自动轮播

二、实现代码

//  手写图片轮播器
//
//  Created by 鑫 on 14-10-9.
//  Copyright (c) 2014年 梁镋鑫. All rights reserved.
//
#define TXImageCount 5

#import "TXViewController.h"


@interface TXViewController ()<UIScrollViewDelegate>
{
    UIScrollView *_scrollView;
    UIPageControl *_pageControl;
}
@property(nonatomic ,strong)NSTimer *timer;

@end

@implementation TXViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    
    _scrollView = [[UIScrollView alloc]initWithFrame:CGRectMake(10, 85, 300, 130)];
    
    //一些固定参数
    CGFloat imageW = _scrollView.frame.size.width;
    CGFloat imageH = _scrollView.frame.size.height;
    CGFloat imageY = 0;
    _scrollView.backgroundColor = [UIColor blackColor];
    [self.view addSubview:_scrollView];
    
    _scrollView.delegate = self;
    //添加五张图片到scrollview中
    for (int i = 0; i<TXImageCount; i++) {
        UIImageView *imageView = [[UIImageView alloc] init];
        
        // 设置frame
        CGFloat imageX = i * imageW;
        imageView.frame = CGRectMake(imageX, imageY, imageW, imageH);
        
        // 设置图片
       NSString *name = [NSString stringWithFormat:@"img_0%d", i + 1];
        imageView.image = [UIImage imageNamed:name];
        [_scrollView addSubview:imageView];
        
        
        //添加定时器
        
        [self addTimer];
        
    
    
    }
    //添加分页点
    _pageControl = [[UIPageControl alloc]initWithFrame:CGRectMake(107, 128, 106, 37)];
    _pageControl.backgroundColor=[UIColor orangeColor];
    
    //设置pageControl的总页数
    
    _pageControl.numberOfPages = TXImageCount;
    
    [_pageControl addTarget:self action:@selector(changPage) forControlEvents:UIControlEventValueChanged];
    [self.view addSubview:_pageControl];
    //设置内容尺寸
    CGFloat contentW =TXImageCount *imageW;
    _scrollView.contentSize = CGSizeMake(contentW, 0);
    
    //隐藏水平滚动条
    _scrollView.showsHorizontalScrollIndicator =NO;
    
    //分页
    _scrollView.pagingEnabled = YES;
    
    
}
/**
 *  点击pageControl改变scrollView的页面
 */
-(void)changPage
{
    CGPoint offest=CGPointMake(_pageControl.currentPage*_scrollView.frame.size.width, 0);
    [_scrollView setContentOffset:offest animated:YES];
}
/**
 *  添加定时器
 */
-(void)addTimer
{
     self.timer = [NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(nextImage) userInfo:nil repeats:YES];
    //提高优先级
    [[NSRunLoop currentRunLoop ] addTimer:self.timer forMode:NSRunLoopCommonModes];
}
/**
 *  移除定时器
 */
-(void)removeTimer
{
    [self.timer invalidate];
    self.timer =nil;
}
-(void)nextImage
{
    //1.增加pageControl的页码
    int page = 0;
    if (_pageControl.currentPage ==TXImageCount-1) {
        page = 0;
    }
    else
    {
        page = _pageControl.currentPage +1;
    }
    //计算scrolview滚动的位置
    CGFloat offsetX = page *_scrollView.frame.size.width;
    CGPoint offset = CGPointMake(offsetX, 0);
    [_scrollView setContentOffset:offset animated:YES];
    
}
#pragma mark  --代理方法

-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    //根据scrollview的滚动位置决定pageControl显示第几页
    CGFloat scrollW = _scrollView.frame.size.width;
    
    int page = (_scrollView.contentOffset.x+scrollW *0.5)/scrollW;
    _pageControl.currentPage =page;
}
- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
/**
 *  停止拖拽时调用
 
 */
-(void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
    // 停止定时器(一旦定时器停止了,就不能再使用)
    [self addTimer];
}

/**
 *  开始拖拽的时候调用
 */
-(void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView
{
    // 停止定时器(一旦定时器停止了,就不能再使用)
    [self removeTimer];
}



@end