//

//  ZQRViewController.m

//  04-图片轮播器

//

//  Created by apple on 17-08-24.

//  Copyright (c) 2017年 zzqqrr. All rights reserved.

//

#define ZQRImageCount 5

#import "ZQRViewController.h"

@interface ZQRViewController () <UIScrollViewDelegate>

@property (weak, nonatomic) IBOutlet UIScrollView *scrollView;

@property (weak, nonatomic) IBOutlet UIPageControl *pageControl;

/**

 *  定时器

 */

@property (nonatomic, strong) NSTimer *timer;

@end

@implementation ZQRViewController

- (void)viewDidLoad

{

    [super viewDidLoad];

    self.scrollView.delegate=self;

    // 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 = ;

    // 1.添加5张图片到scrollView中

    for (int i = ; 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 + ];

        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, );

    // 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 = ;

    if (self.pageControl.currentPage == MJImageCount - ) {

        page = ;

    } else {

        page = self.pageControl.currentPage + ;

    }

    // 2.计算scrollView滚动的位置

    CGFloat offsetX = page * self.scrollView.frame.size.width;

    CGPoint offset = CGPointMake(offsetX, );

    [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