iOS学习：调用相机，选择图片上传，带预览功能

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二、拖控件，创建映射

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三、在.h中加入delegate

1. @interface ViewController : UIViewController

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四、实现按钮事件

1. -(IBAction)chooseImage:(id)sender {
2. UIActionSheet *sheet;
3. // 判断是否支持相机
4. if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
5. {
6. sheet  = [[UIActionSheet alloc] initWithTitle:@"选择" delegate:self cancelButtonTitle:nil destructiveButtonTitle:@"取消" otherButtonTitles:@"拍照",@"从相册选择", nil];
7. }
8. else {
9. sheet = [[UIActionSheet alloc] initWithTitle:@"选择" delegate:self cancelButtonTitle:nil destructiveButtonTitle:@"取消" otherButtonTitles:@"从相册选择", nil];
10. }
11. sheet.tag = 255;
12. [sheet showInView:self.view];
13. }

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五、实现actionSheet delegate事件

1. -(void) actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
2. {
3. if (actionSheet.tag == 255) {
4. NSUInteger sourceType = 0;
5. // 判断是否支持相机
6. if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
7. switch (buttonIndex) {
8. case 0:
9. // 取消
10. return;
11. case 1:
12. // 相机
13. sourceType = UIImagePickerControllerSourceTypeCamera;
14. break;
15. case 2:
16. // 相册
17. sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
18. break;
19. }
20. }
21. else {
22. if (buttonIndex == 0) {
23. return;
24. } else {
25. sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
26. }
27. }
28. // 跳转到相机或相册页面
29. UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];
30. imagePickerController.delegate = self;
31. imagePickerController.allowsEditing = YES;
32. imagePickerController.sourceType = sourceType;
33. [self presentViewController:imagePickerController animated:YES completion:^{}];
34. [imagePickerController release];
35. }
36. }

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六、实现ImagePicker delegate 事件

1. #pragma mark - image picker delegte
2. - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
3. {
4. [picker dismissViewControllerAnimated:YES completion:^{}];
5. UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
6. /* 此处info 有六个值
7. * UIImagePickerControllerMediaType; // an NSString UTTypeImage)
8. * UIImagePickerControllerOriginalImage;  // a UIImage 原始图片
9. * UIImagePickerControllerEditedImage;    // a UIImage 裁剪后图片
10. * UIImagePickerControllerCropRect;       // an NSValue (CGRect)
11. * UIImagePickerControllerMediaURL;       // an NSURL
12. * UIImagePickerControllerReferenceURL    // an NSURL that references an asset in the AssetsLibrary framework
13. * UIImagePickerControllerMediaMetadata    // an NSDictionary containing metadata from a captured photo
14. */
15. // 保存图片至本地，方法见下文
16. [self saveImage:image withName:@"currentImage.png"];
17. NSString *fullPath = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"] stringByAppendingPathComponent:@"currentImage.png"];
18. UIImage *savedImage = [[UIImage alloc] initWithContentsOfFile:fullPath];
19. isFullScreen = NO;
20. [self.imageView setImage:savedImage];
21. self.imageView.tag = 100;
22. }
23. - (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
24. {
25. [self dismissViewControllerAnimated:YES completion:^{}];
26. }

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七、保存图片
高保真压缩图片方法

1. NSData * UIImageJPEGRepresentation ( UIImage *image, CGFloat compressionQuality
2. )

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此方法可将图片压缩，但是图片质量基本不变，第二个参数即图片质量参数。

1. #pragma mark - 保存图片至沙盒
2. - (void) saveImage:(UIImage *)currentImage withName:(NSString *)imageName
3. {
4. NSData *imageData = UIImageJPEGRepresentation(currentImage, 0.5);
5. // 获取沙盒目录
6. NSString *fullPath = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"] stringByAppendingPathComponent:imageName];
7. // 将图片写入文件
8. [imageData writeToFile:fullPath atomically:NO];
9. }

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八、实现点击图片预览功能，滑动放大缩小，带动画

1. -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
2. {
3. isFullScreen = !isFullScreen;
4. UITouch *touch = [touches anyObject];
5. CGPoint touchPoint = [touch locationInView:self.view];
6. CGPoint imagePoint = self.imageView.frame.origin;
7. //touchPoint.x ，touchPoint.y 就是触点的坐标
8. // 触点在imageView内，点击imageView时 放大,再次点击时缩小
9. if(imagePoint.x <= touchPoint.x && imagePoint.x +self.imageView.frame.size.width >=touchPoint.x && imagePoint.y <=  touchPoint.y && imagePoint.y+self.imageView.frame.size.height >= touchPoint.y)
10. {
11. // 设置图片放大动画
12. [UIView beginAnimations:nil context:nil];
13. // 动画时间
14. [UIView setAnimationDuration:1];
15. if (isFullScreen) {
16. // 放大尺寸
17. self.imageView.frame = CGRectMake(0, 0, 320, 480);
18. }
19. else {
20. // 缩小尺寸
21. self.imageView.frame = CGRectMake(50, 65, 90, 115);
22. }
23. // commit动画
24. [UIView commitAnimations];
25. }
26. }

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九、上传图片，使用ASIhttpRequest类库实现，由于本文重点不是网络请求，故不对ASIHttpRequest详细讲述，只贴出部分代码

1. ASIFormDataRequest *requestReport  = [[ASIFormDataRequest alloc] initWithURL:服务器地址];
2. NSString *Path = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"] stringByAppendingPathComponent:@"currentImage.png"];
3. [requestReport setFile:Path forKey:@"picturepath"];
4. [requestReport buildPostBody];
5. requestReport.delegate = self;
6. [requestReport startAsynchronous];

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效果图如下：

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