iOS 使用UIImagePickerController 拍照

    在項目開發的過程當中，咱們常常會使用的iPhone 或者 iPad 的拍照功能，好比給用戶設置頭像，通常都會用到拍照功能。咱們能夠使用UIImagePickerController 類來調用iPhone的攝像頭進行拍照或者錄視頻。iOS 已經爲咱們封裝好了UIImagePickerController ,使用很簡單，讓咱們不用花費不少時間就能夠調用拍照功能。使用UIImagePickerController時，須要實現UIImagePickerController協議。

     在xib中添加一個按鈕，綁定按鈕的響應事件，在響應事件中添加以下代碼：

UIImagePickerControllerSourceType sourceType = UIImagePickerControllerSourceTypeCamera; 
   //判斷是否有攝像頭
   if(![UIImagePickerController isSourceTypeAvailable:sourceType])
    {
        sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    }
    
    UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];
    imagePickerController.delegate = self;   // 設置委託
    imagePickerController.sourceType = sourceType;
    imagePickerController.allowsEditing = YES;
    [self presentViewController:imagePickerController animated:YES completion:nil];  //須要以模態的形式展現
    [imagePickerController release];

    記得要實現UIImagePickerControllerDelegate 中 的- ( void )imagePickerController:( UIImagePickerController *)picker didFinishPickingMediaWithInfo:( NSDictionary *)info 和  

-(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker 兩個方法，分別時拍照完成的時候調用 和 取消拍照的時候調用。代碼以下：

#pragma mark -
#pragma mark UIImagePickerController Method
//完成拍照
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    [picker dismissViewControllerAnimated:YES completion:^{}];
    UIImage *image = [info objectForKey:UIImagePickerControllerEditedImage];
    if (image == nil)
        image = [info objectForKey:UIImagePickerControllerOriginalImage];
    
    [self performSelector:@selector(saveImage:) withObject:image];
    
}
//用戶取消拍照
-(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
    [picker dismissViewControllerAnimated:YES completion:nil];
}

//將照片保存到disk上
-(void)saveImage:(UIImage *)image
{

    NSData *imageData = UIImagePNGRepresentation(image);
    if(imageData == nil)
    {
        imageData = UIImageJPEGRepresentation(image, 1.0);
    }
    
    NSDate *date = [NSDate date];
    
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setDateFormat:@"yyyyMMddHHmmss"];
    _fileName = [[[formatter stringFromDate:date] stringByAppendingPathExtension:@"png"] retain];
    
    
    NSURL *saveURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:_fileName];
    
    [imageData writeToURL:saveURL atomically:YES];
    
    
}