一：简介

在项目中免不了会遇到，实名认证上传身份证、绑定银行卡等功能。在实际操作中呢，会涉及到上传图片，在页面布局时，可能图片不是一张，考虑到布局的美观等因素，显示图片的位置变得很小，如果想查看上传的图片是否清晰，内容是否完整，可能就需要放大才能实现，下面就和大家分享一下我封装的一类，完美的实现了图片的缩放功能。

另外，这些博文都是来源于我日常开发中的技术总结，在时间允许的情况下，我会针对技术点分别分享iOS、Android两个版本，尽量附上demo以供大家参考，如果有其他技术点需要，可在文章后留言，我会尽全力帮助大家。

二：实现思路分析

给UIImageView添加手势

封装一个继承NSObject的FBYImageZoom类

写一个函数用来接收出入的UIImageView

根据传入的UIImageView重新绘制在Window中

添加放大后背景视图的颜色和透明度

使用动画放大展示ImageView

添加恢复ImageView原始尺寸的tap点击事件

完成之后将背景视图删掉

三：实现源码分析

根据实现思路分析，一步步进行编码实现：

1. 给UIImageView添加手势

self.myImageView = [[UIImageView alloc]initWithFrame:CGRectMake(50, 150, SCREEN_WIDTH-100, SCREEN_WIDTH-100)];self.myImageView.image = [UIImage imageNamed:@"bankcard"];//添加点击事件UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(scanBigImageClick:)];[_myImageView addGestureRecognizer:tapGestureRecognizer];[_myImageView setUserInteractionEnabled:YES];[self.view addSubview:_myImageView];

2. 封装一个继承NSObject的FBYImageZoom类

#import <Foundation/Foundation.h>#import <UIKit/UIKit.h>@interface FBYImageZoom : NSObject@end

3. 写一个函数用来接收出入的UIImageView

/** * @param contentImageview 图片所在的imageView */+(void)ImageZoomWithImageView:(UIImageView *)contentImageview;

4. 根据传入的UIImageView重新绘制在Window中

+(void)ImageZoomWithImageView:(UIImageView *)contentImageview{ UIWindow *window = [UIApplication sharedApplication].keyWindow; [self scanBigImageWithImage:contentImageview.image frame:[contentImageview convertRect:contentImageview.bounds toView:window]];}

5. 添加放大后背景视图的颜色和透明度

//当前视图 UIWindow *window = [UIApplication sharedApplication].keyWindow; //背景 UIView *backgroundView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height)]; [backgroundView setBackgroundColor:[UIColor colorWithRed:107/255.0 green:107/255.0 blue:99/255.0 alpha:0.6]];

6. 使用动画放大展示ImageView

//动画放大所展示的ImageView [UIView animateWithDuration:0.4 animations:^{ CGFloat y,width,height; y = ([UIScreen mainScreen].bounds.size.height - image.size.height * [UIScreen mainScreen].bounds.size.width / image.size.width) * 0.5; //宽度为屏幕宽度 width = [UIScreen mainScreen].bounds.size.width; //高度 根据图片宽高比设置 height = image.size.height * [UIScreen mainScreen].bounds.size.width / image.size.width; [imageView setFrame:CGRectMake(0, y, width, height)]; //重要！ 将视图显示出来 [backgroundView setAlpha:1]; } completion:^(BOOL finished) { }];

7. 添加恢复ImageView原始尺寸的tap点击事件

//添加点击事件同样是类方法 -> 作用是再次点击回到初始大小UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(hideImageView:)];[backgroundView addGestureRecognizer:tapGestureRecognizer];/** * 恢复imageView原始尺寸 */+(void)hideImageView:(UITapGestureRecognizer *)tap{ UIView *backgroundView = tap.view; //原始imageview UIImageView *imageView = [tap.view viewWithTag:1024]; //恢复 [UIView animateWithDuration:0.4 animations:^{ [imageView setFrame:oldframe]; [backgroundView setAlpha:0]; } completion:^(BOOL finished) { [backgroundView removeFromSuperview]; }];}

8. 完成之后将背景视图删掉

//完成后操作->将背景视图删掉[backgroundView removeFromSuperview];

四：项目实际使用

1. 引入封装类FBYImageZoom

#import "FBYImageZoom.h"

2. 给UIImageView添加手势

//添加点击事件UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(scanBigImageClick:)];

3. 调用封装类函数

//浏览大图点击事件-(void)scanBigImageClick:(UITapGestureRecognizer *)tap{ NSLog(@"点击图片"); UIImageView *clickedImageView = (UIImageView *)tap.view; [FBYImageZoom ImageZoomWithImageView:clickedImageView];}

好了，到这里点击图片放大到全屏就完成了

4. 长按保存图片

另外就是实现长按保存图片的功能，这个功能很简单

首先增加长按手势

//创建长按手势 UILongPressGestureRecognizer *longTap = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(imglongTapClick:)]; //添加手势 [_myImageView addGestureRecognizer:longTap];

然后长按手势弹出警告视图确认

-(void)imglongTapClick:(UILongPressGestureRecognizer*)gesture{ if(gesture.state==UIGestureRecognizerStateBegan) { UIAlertController *alertControl = [UIAlertController alertControllerWithTitle:@"保存图片" message:nil preferredStyle:UIAlertControllerStyleAlert]; UIAlertAction *cancel = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) { NSLog(@"取消保存图片"); }]; UIAlertAction *confirm = [UIAlertAction actionWithTitle:@"确认" style:UIAlertActionStyleDestructive handler:^(UIAlertAction * _Nonnull action) { NSLog(@"确认保存图片"); // 保存图片到相册 UIImageWriteToSavedPhotosAlbum(self.myImageView.image,self,@selector(imageSavedToPhotosAlbum:didFinishSavingWithError:contextInfo:),nil); }]; [alertControl addAction:cancel]; [alertControl addAction:confirm]; [self presentViewController:alertControl animated:YES completion:nil]; } }

最后保存图片后的回调

- (void)imageSavedToPhotosAlbum:(UIImage*)image didFinishSavingWithError: (NSError*)error contextInfo:(id)contextInfo{ NSString *message; if(!error) { message =@"成功保存到相册"; UIAlertController *alertControl = [UIAlertController alertControllerWithTitle:@"提示" message:message preferredStyle:UIAlertControllerStyleAlert]; UIAlertAction *action = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDestructive handler:^(UIAlertAction * _Nonnull action) { }]; [alertControl addAction:action]; [self presentViewController:alertControl animated:YES completion:nil]; }else { message = [error description]; UIAlertController *alertControl = [UIAlertController alertControllerWithTitle:@"提示" message:message preferredStyle:UIAlertControllerStyleAlert]; UIAlertAction *action = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) { }]; [alertControl addAction:action]; [self presentViewController:alertControl animated:YES completion:nil]; } }

到这里实现点击图片放大和长按保存图片功能就都是实现了，demo源码已经放在github上。

五：项目展示

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。