本文实例为大家分享了iOS实现图片自动切换的具体代码，供大家参考，具体内容如下
#import "ViewController.h"
#define ImageViewCount 5
@interface ViewController ()<UIScrollViewDelegate>
@property (weak, nonatomic) IBOutlet UIScrollView *imageScrollView;
@property (weak, nonatomic) IBOutlet UIPageControl *imageViewPageControl;
@property (strong, nonatomic) NSTimer *timer;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
[self addImageView2ScrollView];
self.imageScrollView.contentSize = CGSizeMake(self.imageScrollView.frame.size.width * ImageViewCount, 0);
self.imageScrollView.delegate = self;
self.imageScrollView.pagingEnabled = YES;//UIScrollView支持拖动分页
self.imageViewPageControl.numberOfPages = ImageViewCount;
[self addScrollTimer];
}
- (void)rotatePic{
int currentPageIndex = self.imageViewPageControl.currentPage;
if(++currentPageIndex == 5){
currentPageIndex = 0;
}
CGFloat offsetX = currentPageIndex * self.imageScrollView.frame.size.width;
[UIView animateWithDuration:1 animations:^{
self.imageScrollView.contentOffset = CGPointMake(offsetX, 0);
}];
}
- (void)addImageView2ScrollView{
CGFloat imageWidth = self.imageScrollView.frame.size.width;
CGFloat imageHeight = self.imageScrollView.frame.size.height;
for(int i = 0;i <= ImageViewCount;i++){
UIImageView *imageInScroll = [[UIImageView alloc] init];
imageInScroll.frame = CGRectMake(i * imageWidth, 0, imageWidth, imageHeight);
imageInScroll.image = [UIImage imageNamed:[NSString stringWithFormat:@"img_%02d",i + 1]];
[self.imageScrollView addSubview:imageInScroll];
}
}
// 正滚动时执行
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
CGFloat offX = self.imageScrollView.contentOffset.x;//（0，0）距离content内部左上顶点的x轴长度
NSLog(@"~~~~~~~%f ^^^^^^%f", offX, self.imageScrollView.frame.size.width);
int currentPageIndex = (offX + .5f * self.imageScrollView.frame.size.width) / self.imageScrollView.frame.size.width;
self.imageViewPageControl.currentPage = currentPageIndex;
}
- (void)addScrollTimer{
self.timer = [NSTimer timerWithTimeInterval:2 target:self selector:@selector(rotatePic) userInfo:nil repeats:YES];
[[NSRunLoop mainRunLoop] addTimer:self.timer forMode:NSRunLoopCommonModes];
}
- (void)removeScrollTimer{
[self.timer invalidate];//释放定时器
self.timer = nil;
}
// 开始准备滚动时执行 移除定时滚动操作
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
NSLog(@"~~~scrollViewWillBeginDragging");
[self removeScrollTimer];
}
// 结束滚动后执行 添加定时滚动操作
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{
NSLog(@"~~~scrollViewDidEndDragging");
[self addScrollTimer];
}
@end对UIScrollView的运用，以上代码中有详细注释，需注意2点：
注意设置contentSize属性。其中contentSize表示scroll内容尺寸大小
注意设置代理UIScrollViewDelegate，才可调用其中的方法
对于定时器NSTimer的运用需注意
在线程的loop中添加定时器
注意使用完成回收NSTimer
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持编程网。
