IOS SDK详解之拍照/相册（默认＋自定义拍照界面）

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blog.csdn.net/hello_hwc

前言：
本来要更新NSURLSession的UploadTask的，结果写那个Demo的时候想要写成拍照上传，然后就想到先写一个关于拍照的Demo吧。本文会先介绍下如何使用系统提供的界面拍照和选择相册，然后自定义拍照界面。注意，本文使用的是UIImagePickerController,所以不能完全的自定义，如果想要彻底的自定义拍照，建议选择AV Foundation这个框架来做

Demo效果
进入系统的拍照界面

进入自定义拍照界面

自定义前置摄像头和后置摄像头切换动画－翻页

一 使用系统提供的界面拍照和相册选择

第一步
保存一个UIImagePickerController的实例，然后适当的时候初始化始化。Demo选择在viewDidLoad初始化。让当前类实现UIImagePickerControllerDelegate,UINavigationControllerDelegate两个代理

@property (strong,nonatomic)UIImagePickerController * imagePikerViewController;
//初始化
self.imagePikerViewController = [[UIImagePickerController alloc] init];
self.imagePikerViewController.delegate = self;//通过代理来传递拍照的图片
self.imagePikerViewController.allowsEditing = YES;//允许编辑

第二步，通过ActionSheet来让用户选择是拍照还是到相册选择，然后模态的显示

[self presentViewController:self.imagePikerViewController animated:YES completion:NULL];

注意，要先判断相机是否可用，然后在进入相机（有可能相机坏了，或者在虚拟机上运行的）

UIAlertController * alertController = [UIAlertController alertControllerWithTitle: nil
                                                                              message: nil
                                                                       preferredStyle:UIAlertControllerStyleActionSheet];

    [alertController addAction: [UIAlertAction actionWithTitle: @"Take Photo" style: UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
        if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]){
            self.imagePikerViewController.sourceType = UIImagePickerControllerSourceTypeCamera;
            [self presentViewController:self.imagePikerViewController animated:YES completion:NULL];
        }else{
            [self showAlertWithMessage:@"Camera is not available in this device or simulator"];
        }
    }]];
    [alertController addAction: [UIAlertAction actionWithTitle: @"Choose Existing Photo" style: UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
        if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]){
            self.imagePikerViewController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
            [self presentViewController:self.imagePikerViewController animated:YES completion:NULL];
        }
    }]];
    [alertController addAction: [UIAlertAction actionWithTitle: @"Cancel" style: UIAlertActionStyleCancel handler:nil]];
    [self presentViewController: alertController animated: YES completion: nil];

第三部，代理函数处理拍照或者cancel事件

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{
    UIImage * image = info[UIImagePickerControllerEditedImage];
    if (!image) {
        image = info[UIImagePickerControllerOriginalImage];
    }
    self.imageview.image = image;
    [self dismissViewControllerAnimated:YES completion:NULL];
}
-(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{
    [self dismissViewControllerAnimated:YES completion:NULL];
}

二 自定义拍照界面

UIImagePickerController的自定义界面比较简单，通过设置cameraOverlayView这个属性为自定义的View就能自定义。
第一步 创建一个View
创建xib文件

拖拽控件，进行autoLayout，最终效果如图

把fileOwner设置成CustomTakePhotoViewController

第二步 在显示拍照界面之前，把UI设置成自己想要的，注意，把属性
showsCameraControls设置为NO，不让默认的界面出现。

self.imagePikerViewController.sourceType = UIImagePickerControllerSourceTypeCamera;
self.imagePikerViewController.showsCameraControls = NO;
[[NSBundle mainBundle] loadNibNamed:@"CustomOverLayview" owner:self options:nil];
self.takePictureButton.layer.cornerRadius = 20;
self.takePictureButton.clipsToBounds = YES;
self.overlayView.frame = self.imagePikerViewController.cameraOverlayView.frame;
self.overlayView.backgroundColor = [UIColor clearColor];
self.imagePikerViewController.cameraOverlayView = self.overlayView;
self.overlayView = nil;
[self presentViewController:self.imagePikerViewController animated:YES completion:NULL];

第三步，为view上的控件添加动作
Segment Control负责切换前置摄像头和后置摄像头，为了流畅，在切换的时候显示动画。

- (IBAction)cameraSelect:(UISegmentedControl *)sender{
    NSInteger index = sender.selectedSegmentIndex;

    if (index == 0) {
        [UIView transitionWithView:self.imagePikerViewController.view duration:1.0 options:UIViewAnimationOptionAllowAnimatedContent | UIViewAnimationOptionTransitionCurlDown animations:^{
            self.imagePikerViewController.cameraDevice = UIImagePickerControllerCameraDeviceFront;
        } completion:NULL];
    }else{
        [UIView transitionWithView:self.imagePikerViewController.view duration:1.0 options:UIViewAnimationOptionAllowAnimatedContent | UIViewAnimationOptionTransitionCurlUp animations:^{
            [self.imagePikerViewController setCameraDevice:UIImagePickerControllerCameraDeviceRear];
        } completion:NULL];
    }
}

拍照的Button

- (IBAction)takePicture:(id)sender {
    [self.imagePikerViewController takePicture];
}

取消的Button

- (IBAction)cancelTakePicture:(id)sender {
    [self dismissViewControllerAnimated:YES completion:NULL];
}

第四步 在代理中处理图片

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{
    UIImage * image = info[UIImagePickerControllerEditedImage];
    if (!image) {
        image = info[UIImagePickerControllerOriginalImage];
    }
    self.imageview.image = image;
    [self dismissViewControllerAnimated:YES completion:NULL];
}

注意，如果log输出

Snapshotting a view that has not been rendered results in an empty snapshot. Ensure your view has been rendered at least once before snapshotting or snapshot after screen updates.

直接忽略就是了，没有任何影响，貌似是IOS 8的一个bug

下载链接
http://download.csdn.net/detail/hello_hwc/8553539