iOS实现点击图片放大和长按保存图片的示例

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

1. 给uiimageview添加手势
2. 封装一个继承nsobject的fbyimagezoom类
3. 写一个函数用来接收出入的uiimageview
4. 根据传入的uiimageview重新绘制在window中
5. 添加放大后背景视图的颜色和透明度
6. 使用动画放大展示imageview
7. 添加恢复imageview原始尺寸的tap点击事件
8. 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。