iOS如何实现点击图片放大和长按保存图片
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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。
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#import @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
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