提到從攝像頭/相冊獲取圖片是面向終端用戶的，由用戶去瀏覽并選擇圖片為程序使用。在這里，我們需要過UIImagePickerController類來和用戶交互。
使用UIImagePickerController和用戶交互，我們需要實現2個協議<UIImagePickerControllerDelegate,UINavigationControllerDelegate>。
View Code
代碼如下復制代碼
pragma mark 從用戶相冊獲取活動圖片

(void)pickImageFromAlbum

{

imagePicker = [[UIImagePickerController alloc] init];

imagePicker.delegate =self;

imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

imagePicker.modalTransitionStyle = UIModalTransitionStyleCoverVertical;

imagePicker.allowsEditing =YES;



[self presentModalViewController:imagePicker animated:YES];


}
我們來看看上面的從相冊獲取圖片，我們首先要實例化UIImagePickerController對象，然后設置imagePicker對象為當前對象，設置imagePicker的圖片來源為UIImagePickerControllerSourceTypePhotoLibrary，表明當前圖片的來源為相冊，除此之外還可以設置用戶對圖片是否可編輯。
View Code
代碼如下復制代碼
pragma mark 從攝像頭獲取活動圖片

(void)pickImageFromCamera

{

imagePicker = [[UIImagePickerController alloc] init];

imagePicker.delegate =self;

imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;

imagePicker.modalTransitionStyle = UIModalTransitionStyleCoverVertical;

imagePicker.allowsEditing =YES;



[self presentModalViewController:imagePicker animated:YES];


}
//打開相機

(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;//自定義照片樣式

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


}
以上是從攝像頭獲取圖片，和從相冊獲取圖片只是圖片來源的設置不一樣，攝像頭圖片的來源為UIImagePickerControllerSourceTypeCamera。
　　　　在和用戶交互之后，用戶選擇好圖片后，會回調選擇結束的方法。
-(void)imagePickerController:(UIImagePickerController)picker didFinishPickingMediaWithInfo:(NSDictionary)info
{

//初始化imageNew為從相機中獲得的--

UIImage *imageNew = [info objectForKey:@"UIImagePickerControllerOriginalImage"];

//設置image的尺寸

CGSize imagesize = imageNew.size;

imagesize.height =626;

imagesize.width =413;

//對圖片大小進行壓縮--

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];


}
//對圖片尺寸進行壓縮--
-(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;
}
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