IOS中实现图片全屏预览的功能

//// ViewController.m// XWZoomImageView//// Created by xiao on 15/11/13.// Copyright © 2015年 xiao. All rights reserved.//#import "ViewController.h"@interface ViewController ()<UIScrollViewDelegate>@property (weak, nonatomic) IBOutlet UIImageView *picView;@property (weak, nonatomic) UIScrollView *scrollView;@property (weak, nonatomic) UIImageView *lastImageView;@property (nonatomic, assign)CGRect originalFrame;@property (nonatomic, assign)BOOL isDoubleTap;@end@implementation ViewController- (void)viewDidLoad { [super viewDidLoad];  self.picView.userInteractionEnabled = YES; //添加单击手势 UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(showZoomImageView:)]; [self.picView addGestureRecognizer:tap]; }-(void)showZoomImageView:(UITapGestureRecognizer *)tap{ if (![(UIImageView *)tap.view image]) {  return; } //scrollView作为背景 UIScrollView *bgView = [[UIScrollView alloc] init]; bgView.frame = [UIScreen mainScreen].bounds; bgView.backgroundColor = [UIColor blackColor]; UITapGestureRecognizer *tapBg = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapBgView:)]; [bgView addGestureRecognizer:tapBg];  UIImageView *picView = (UIImageView *)tap.view;  UIImageView *imageView = [[UIImageView alloc] init]; imageView.image = picView.image; imageView.frame = [bgView convertRect:picView.frame fromView:self.view]; [bgView addSubview:imageView];  [[[UIApplication sharedApplication] keyWindow] addSubview:bgView];  self.lastImageView = imageView; self.originalFrame = imageView.frame; self.scrollView = bgView; //最大放大比例 self.scrollView.maximumZoomScale = 1.5; self.scrollView.delegate = self;  [UIView animateWithDuration:0.5 animations:^{  CGRect frame = imageView.frame;  frame.size.width = bgView.frame.size.width;  frame.size.height = frame.size.width * (imageView.image.size.height / imageView.image.size.width);  frame.origin.x = 0;  frame.origin.y = (bgView.frame.size.height - frame.size.height) * 0.5;  imageView.frame = frame; }];}-(void)tapBgView:(UITapGestureRecognizer *)tapBgRecognizer{ self.scrollView.contentOffset = CGPointZero; [UIView animateWithDuration:0.5 animations:^{  self.lastImageView.frame = self.originalFrame;  tapBgRecognizer.view.backgroundColor = [UIColor clearColor]; } completion:^(BOOL finished) {  [tapBgRecognizer.view removeFromSuperview];  self.scrollView = nil;  self.lastImageView = nil; }];}//返回可缩放的视图-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{ return self.lastImageView;}

.h文件-----------------------------------------------------------------#import@interface ZoomImage : NSObject/** *@brief点击图片放大,再次点击缩小 * *@param oldImageView 头像所在的imageView */+(void)showImage:(UIImageView*)avatarImageView;@end.m文件-----------------------------------------------------------------#import "ZoomImage.h"static CGRect oldframe;@implementation ZoomImage+(void)showImage:(UIImageView*)avatarImageView{ UIImage *image =avatarImageView.image; // 获得根窗口 UIWindow *window =[UIApplication sharedApplication].keyWindow; UIView *backgroundView =[[UIView alloc]initWithFrame:CGRectMake(0, 0, WIDTH, HEIGHT)]; oldframe =[avatarImageView convertRect:avatarImageView.bounds toView:window]; backgroundView.backgroundColor =[UIColor blackColor]; backgroundView.alpha =0.5; UIImageView *imageView =[[UIImageView alloc]initWithFrame:oldframe]; imageView.image =image; imageView.tag =1; [backgroundView addSubview:imageView]; [window addSubview:backgroundView]; //点击图片缩小的手势 UITapGestureRecognizer *tap =[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(hideImage:)]; [backgroundView addGestureRecognizer:tap]; [UIView animateWithDuration:0.3 animations:^{  imageView.frame =CGRectMake(0,([UIScreen mainScreen].bounds.size.height-image.size.height*[UIScreen mainScreen].bounds.size.width/image.size.width)/2, [UIScreen mainScreen].bounds.size.width, image.size.height*[UIScreen mainScreen].bounds.size.width/image.size.width);  backgroundView.alpha =1; }];}+(void)hideImage:(UITapGestureRecognizer *)tap{ UIView *backgroundView =tap.view; UIImageView *imageView =(UIImageView *)[tap.view viewWithTag:1]; [UIView animateWithDuration:0.3 animations:^{  imageView.frame =oldframe;  backgroundView.alpha =0;   } completion:^(BOOL finished) {  [backgroundView removeFromSuperview]; }];}