iOS图片上传及处理

从摄像头或者是从相冊中读取图片。须要通过UIImagePickerController类来实现，在使用UIImagePickerController时，须要是实现以下两个协议

<UINavigationControllerDelegate,UIImagePickerControllerDelegate>

1、从相冊中读取图片
首先要实例化UIImagePickerController对象imagePicker。设置imagePicker的图片来源为UIImagePickerControllerSourceTypePhotoLibrary，表明当前图片的来源为用户的相冊。

以及设置图片是否可被编辑allowsEditing。

#pragma mark - 从用户相冊获取图片
- (void)pickImageFromAlbum
{
imagePicker = [[UIImagePickerController alloc] init];
imagePicker.delegate =self;
imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
imagePicker.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
imagePicker.allowsEditing =YES;

[self presentModalViewController:imagePicker animated:YES];
}

2、从相冊中读取图片

#pragma mark - 从摄像头获取图片
- (void)pickImageFromCamera
{
imagePicker = [[UIImagePickerController alloc] init];
imagePicker.delegate =self;
imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
imagePicker.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
imagePicker.allowsEditing =YES;

[self presentModalViewController:imagePicker animated:YES];
}
//打开相机
- (IBAction)touch_photo:(id)sender {
// for iphone
UIImagePickerController *pickerImage = [[UIImagePickerController alloc] init];
if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
pickerImage.sourceType = UIImagePickerControllerSourceTypeCamera;
pickerImage.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:pickerImage.sourceType];

}
pickerImage.delegate =self;
pickerImage.allowsEditing =YES;//自己定义照片样式
[self presentViewController:pickerImage animated:YES completion:nil];
}

在用户现则好图片后。会回调选择结束的方法

-(void)imagePickerController:(UIImagePickerController*)picker didFinishPickingMediaWithInfo:(NSDictionary*)info
{
//初始化imageNew为从相机中获得的--
UIImage *imageNew = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
//设置image的尺寸
CGSize imagesize = imageNew.size;
imageSize.height =626;
imageSize.width =413;
//对图片大小进行压缩--
imageNew = [self imageWithImage:imageNew scaledToSize:imageSize];
NSData *imageData = UIImageJPEGRepresentation(imageNew,0.00001);
if(m_selectImage==nil)
{
m_selectImage = [UIImage imageWithData:imageData];
NSLog(@"m_selectImage:%@",m_selectImage);
[self.takePhotoButton setImage:m_selectImage forState:UIControlStateNormal];
[picker dismissModalViewControllerAnimated:YES];
return ;
}
}

对图片进行压缩

-(UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize
{
// Create a graphics image context
UIGraphicsBeginImageContext(newSize);

// Tell the old image to draw in this new context, with the desired
// new size
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];

// Get the new image from the context
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();

// End the context
UIGraphicsEndImageContext();

// Return the new image.
return newImage;
}

将图片保存到Documents文件夹及PNG、JPEG格式相互转换

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary*)info {
NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
if ([mediaType isEqualToString:@"public.image"]){
image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
NSData *data;
if (UIImagePNGRepresentation(image) == nil) {
data = UIImageJPEGRepresentation(image, 1);
} else {
data = UIImagePNGRepresentation(image);
}

NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *filePath = [NSString stringWithString:[self getPath:@"image1"]];         //将图片存储到本地documents
[fileManager createDirectoryAtPath:filePath withIntermediateDirectories:YES attributes:nil error:nil];
[fileManager createFileAtPath:[filePath stringByAppendingString:@"/image.png"] contents:dataAttributes:nil];

UIImage *editedImage = [[UIImage alloc] init];
editedImage = image;
CGRect rect = CGRectMake(0, 0, 64, 96);
UIGraphicsBeginImageContext(rect.size);
[editedImage drawInRect:rect];
editedImage = UIGraphicsGetImageFromCurrentImageContext();

UIButton *imageButton = [UIButton buttonWithType:UIButtonTypeCustom];
imageButton.frame = CGRectMake(10, 10, 64, 96);
[imageButton setImage:editedImage forState:UIControlStateNormal];
[self.view addSubview:imageButton];
[imageButton addTarget:self action:@selector(imageAction:)forControlEvents:UIControlEventTouchUpInside];
[self dismissModalViewControllerAnimated:YES];
} else {
NSLog(@"Media");
}

在上面的方法中不能得到图片的名称及格式。所以须要将其转换成NSData二进制存储

image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
NSData *data;
if (UIImagePNGRepresentation(image) == nil) {
data = UIImageJPEGRepresentation(image, 1);
} else {
data = UIImagePNGRepresentation(image);
}

[fileManager createFileAtPath:[filePath stringByAppendingString:@"/image.png"] contents:data attributes:nil];  //将图片保存为PNG格式
[fileManager createFileAtPath:[filePath stringByAppendingString:@"/image.jpg"] contents:data attributes:nil]; //将图片保存为JPEG格式

【參考资料：http://www.open-open.com/】