iOS 實現點選圖片放大&長按儲存圖片
阿新 • • 發佈：2019-01-14
一：簡介
在專案中免不了會遇到，實名認證上傳身份證、繫結銀行卡等功能。在實際操作中呢，會涉及到上傳圖片，在頁面佈局時，可能圖片不是一張，考慮到佈局的美觀等因素，顯示圖片的位置變得很小，如果想檢視上傳的圖片是否清晰，內容是否完整，可能就需要放大才能實現，下面就和大家分享一下我封裝的一類，完美的實現了圖片的縮放功能。
另外，這些博文都是來源於我日常開發中的技術總結，在時間允許的情況下，我會針對技術點分別分享iOS、Android兩個版本，儘量附上demo以供大家參考，如果有其他技術點需要，可在文章後留言，我會盡全力幫助大家。
二：實現思路分析
-
給UIImageView新增手勢
-
封裝一個繼承NSObject的FBYImageZoom類
-
寫一個函式用來接收出入的UIImageView
-
根據傳入的UIImageView重新繪製在Window中
-
新增放大後背景檢視的顏色和透明度
-
使用動畫放大展示ImageView
-
新增恢復ImageView原始尺寸的tap點選事件
-
完成之後將背景檢視刪掉
三：實現原始碼分析
根據實現思路分析，一步步進行編碼實現：
1. 給UIImageView新增手勢
self.myImageView = [[UIImageView alloc]initWithFrame:CGRectMake(50, 150, SCREEN_WIDTH-100, SCREEN_WIDTH-100)]; self.myImageView.image = [UIImage imageNamed:@"bankcard"]; //新增點選事件 UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(scanBigImageClick:)]; [_myImageView addGestureRecognizer:tapGestureRecognizer]; [_myImageView setUserInteractionEnabled:YES]; [self.view addSubview:_myImageView];
2. 封裝一個繼承NSObject的FBYImageZoom類
#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
@interface FBYImageZoom : NSObject
@end-
3. 寫一個函式用來接收出入的UIImageView
-
/** * @param contentImageview 圖片所在的imageView */ +(void)ImageZoomWithImageView:(UIImageView *)contentImageview;4. 根據傳入的UIImageView重新繪製在Window中
+(void)ImageZoomWithImageView:(UIImageView *)contentImageview{ UIWindow *window = [UIApplication sharedApplication].keyWindow; [self scanBigImageWithImage:contentImageview.image frame:[contentImageview convertRect:contentImageview.bounds toView:window]]; }5. 新增放大後背景檢視的顏色和透明度
//當前檢視 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. 使用動畫放大展示ImageView
-
//動畫放大所展示的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; //寬度為螢幕寬度 width = [UIScreen mainScreen].bounds.size.width; //高度 根據圖片寬高比設定 height = image.size.height * [UIScreen mainScreen].bounds.size.width / image.size.width; [imageView setFrame:CGRectMake(0, y, width, height)]; //重要！ 將檢視顯示出來 [backgroundView setAlpha:1]; } completion:^(BOOL finished) { }];7. 新增恢復ImageView原始尺寸的tap點選事件
-
//新增點選事件同樣是類方法 -> 作用是再次點選回到初始大小 UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(hideImageView:)]; [backgroundView addGestureRecognizer:tapGestureRecognizer]; /** * 恢復imageView原始尺寸 */ +(void)hideImageView:(UITapGestureRecognizer *)tap{ UIView *backgroundView = tap.view; //原始imageview UIImageView *imageView = [tap.view viewWithTag:1024]; //恢復 [UIView animateWithDuration:0.4 animations:^{ [imageView setFrame:oldframe]; [backgroundView setAlpha:0]; } completion:^(BOOL finished) { [backgroundView removeFromSuperview]; }]; }8. 完成之後將背景檢視刪掉
-
//完成後操作->將背景檢視刪掉 [backgroundView removeFromSuperview];四：專案實際使用
1. 引入封裝類FBYImageZoom
-
#import "FBYImageZoom.h"2. 給UIImageView新增手勢
//新增點選事件 UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(scanBigImageClick:)];3. 呼叫封裝類函式
//瀏覽大圖點選事件 -(void)scanBigImageClick:(UITapGestureRecognizer *)tap{ NSLog(@"點選圖片"); UIImageView *clickedImageView = (UIImageView *)tap.view; [FBYImageZoom ImageZoomWithImageView:clickedImageView]; }好了，到這裡點選圖片放大到全屏就完成了
4. 長按儲存圖片
另外就是實現長按儲存圖片的功能，這個功能很簡單
- 首先增加長按手勢
-
//建立長按手勢 UILongPressGestureRecognizer *longTap = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(imglongTapClick:)]; //新增手勢 [_myImageView addGestureRecognizer:longTap]; 然後長按手勢彈出警告檢視確認 -(void)imglongTapClick:(UILongPressGestureRecognizer*)gesture { if(gesture.state==UIGestureRecognizerStateBegan) { UIAlertController *alertControl = [UIAlertController alertControllerWithTitle:@"儲存圖片" message:nil preferredStyle:UIAlertControllerStyleAlert]; UIAlertAction *cancel = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) { NSLog(@"取消儲存圖片"); }]; UIAlertAction *confirm = [UIAlertAction actionWithTitle:@"確認" style:UIAlertActionStyleDestructive handler:^(UIAlertAction * _Nonnull action) { NSLog(@"確認儲存圖片"); // 儲存圖片到相簿 UIImageWriteToSavedPhotosAlbum(self.myImageView.image,self,@selector(imageSavedToPhotosAlbum:didFinishSavingWithError:contextInfo:),nil); }]; [alertControl addAction:cancel]; [alertControl addAction:confirm]; [self presentViewController:alertControl animated:YES completion:nil]; } } - 最後儲存圖片後的回撥
- (void)imageSavedToPhotosAlbum:(UIImage*)image didFinishSavingWithError: (NSError*)error contextInfo:(id)contextInfo
{
NSString *message;
if(!error) {
message [email protected]"成功儲存到相簿";
UIAlertController *alertControl = [UIAlertController alertControllerWithTitle:@"提示" message:message preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction *action = [UIAlertAction actionWithTitle:@"確定" 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:@"確定" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
}];
[alertControl addAction:action];
[self presentViewController:alertControl animated:YES completion:nil];
}
}-
到這裡實現點選圖片放大和長按儲存圖片功能就都是實現了，demo原始碼已經放在github上。
五：專案展示
-