//
// MJViewController.m
// 04-图片轮播器
//
// Created by apple on 14-3-29.
// Copyright (c) 2014年 itcast. All rights reserved.
//
#define MJImageCount 5
#import "MJViewController.h"
@interface MJViewController () <UIScrollViewDelegate>
@property (weak, nonatomic) IBOutlet UIScrollView *scrollView;
@property (weak, nonatomic) IBOutlet UIPageControl *pageControl;
/**
* 定时器
*/
@property (nonatomic, strong) NSTimer *timer;
@end
@implementation MJViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// 0.一些固定的尺寸参数
CGFloat imageW = self.scrollView.frame.size.width;
CGFloat imageH = self.scrollView.frame.size.height;
CGFloat imageY = 0;
// 1.添加5张图片到scrollView中
for (int i = 0; i<MJImageCount; 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];
[self.scrollView addSubview:imageView];
}
// 2.设置内容尺寸
CGFloat contentW = MJImageCount * imageW;
self.scrollView.contentSize = CGSizeMake(contentW, 0);
// 3.隐藏水平滚动条
self.scrollView.showsHorizontalScrollIndicator = NO;
// 4.分页
self.scrollView.pagingEnabled = YES;
// self.scrollView.delegate = self;
// 5.设置pageControl的总页数
self.pageControl.numberOfPages = MJImageCount;
// 6.添加定时器(每隔2秒调用一次self 的nextImage方法)
[self addTimer];
}
/**
* 添加定时器
*/
- (void)addTimer
{
self.timer = [NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(nextImage) userInfo:nil repeats:YES];
[[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 (self.pageControl.currentPage == MJImageCount - 1) {
page = 0;
} else {
page = self.pageControl.currentPage + 1;
}
// 2.计算scrollView滚动的位置
CGFloat offsetX = page * self.scrollView.frame.size.width;
CGPoint offset = CGPointMake(offsetX, 0);
[self.scrollView setContentOffset:offset animated:YES];
}
#pragma mark - 代理方法
/**
* 当scrollView正在滚动就会调用
*/
- (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;
self.pageControl.currentPage = page;
}
/**
* 开始拖拽的时候调用
*/
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
// 停止定时器(一旦定时器停止了,就不能再使用)
[self removeTimer];
}
/**
* 停止拖拽的时候调用
*/
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
// 开启定时器
[self addTimer];
}
@end