提到从摄像头/相册获取图片是面向终端用户的，由用户去浏览并选择图片为程序使用。在这里，我们需要过UIImagePickerController类来和用户交互。

使用UIImagePickerController和用户交互，我们需要实现2个协议<UIImagePickerControllerDelegate,UINavigationControllerDelegate>。

View Code

代码如下复制代码

#pragma mark 从用户相册获取活动图片

- (void)pickImageFromAlbum

{

imagePicker = [[UIImagePickerController alloc] init];

imagePicker.delegate =self;

imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

imagePicker.modalTransitionStyle = UIModalTransitionStyleCoverVertical;

imagePicker.allowsEditing =YES;

[self presentModalViewController:imagePicker animated:YES];

}

我们来看看上面的从相册获取图片，我们首先要实例化UIImagePickerController对象，然后设置imagePicker对象为当前对象，设置imagePicker的图片来源为UIImagePickerControllerSourceTypePhotoLibrary，表明当前图片的来源为相册，除此之外还可以设置用户对图片是否可编辑。

View Code

代码如下复制代码

#pragma mark 从摄像头获取活动图片

- (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;//自定义照片样式

[self presentViewController:pickerImage animated:YES completion:nil];

}

以上是从摄像头获取图片，和从相册获取图片只是图片来源的设置不一样，摄像头图片的来源为UIImagePickerControllerSourceTypeCamera。

在和用户交互之后，用户选择好图片后，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.TakePhotoBtn setImage:m_selectImage forState:UIControlStateNormal];

[picker dismissModalViewControllerAnimated:YES];

return ;

}

[picker release];

}

//对图片尺寸进行压缩--

-(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;

}

图片保存到本地document里面--以及图片格式的转换