ios--摄像头使用--UIImagePickerController

忘是亡心i 2022-08-10 16:51 198阅读 0赞

IOS有两种拍照与拍摄视频的方式

1.  直接使用[UIImagePickerController][], 这可以提供一个简单便捷的拍照与选择图库里图片的功能.

2.另一种方式就是通过[AV Foundation framework][],来完全自定义拍照的界面与选择图库的界面.

这里介绍第一种, 如何使用[UIImagePickerController][].

一.拍照

步骤

1. 定义[UIImagePickerController][], 启动拍照界面

(1)首先摄像头对于你的应用是必须的,那你应该在项目的Info.plist的Required device capabilities里添加自己要的设备.[这里][Link 1]有相关的设备描述.

(2) 要确保你的设备可用,所以在代码中最好先用UIImagePickerController的[isSourceTypeAvailable:][isSourceTypeAvailable]方面来判断一下,否则如果直接写逻辑,那在设备不可用时,程序会抛异常.

(3)  在拍摄完后,想要能够关掉拍摄界面,那就必须要实现[UIImagePickerControllerDelegate][]

[UIImagePickerController][] 里有几个比较重要的属性.

Source type:  这个参数是用来确定是调用摄像头还是调用图片库.如果是 UIImagePickerControllerSourceTypeCamera 就是调用摄像头,如果是UIImagePickerControllerSourceTypePhotoLibrary 就是调用图片库,如果是UIImagePickerControllerSourceTypeSavedPhotosAlbum 则调用iOS设备中的胶卷相机的图片.

Media types:在拍照时,用来指定是拍静态的图片还是录像.`kUTTypeImage` 表示静态图片, `kUTTypeMovie表示录像.`

Editing controls :用来指定是否可编辑.将`allowsEditing` 属性设置为YES表示可编辑,NO表示不可编辑.

示例代码:(来源于apple官方文档)

[![复制代码][copycode.gif]][copycode.gif 1]

- (BOOL) startCameraControllerFromViewController: (UIViewController*) controller
                                       usingDelegate: (id <UIImagePickerControllerDelegate,
                                               UINavigationControllerDelegate>) delegate 
    {
    
        // here, check the device is available  or not
        if (([UIImagePickerController isSourceTypeAvailable:
                    UIImagePickerControllerSourceTypeCamera] == NO)
                || (delegate == nil)|| (controller == nil))
            return NO;
    
        UIImagePickerController *cameraUI = [[UIImagePickerController alloc] init];
    
        cameraUI.sourceType = UIImagePickerControllerSourceTypeCamera;
    
        // Displays a control that allows the user to choose picture or
        // movie capture, if both are available:
    
        cameraUI.mediaTypes = [UIImagePickerControlleravailableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];
    
        // Hides the controls for moving & scaling pictures, or for
        // trimming movies. To instead show the controls, use YES.
        cameraUI.allowsEditing = NO;
        cameraUI.delegate = delegate;
    
        [controller presentModalViewController: cameraUI animated: YES];
    
        returnYES;
    }

[![复制代码][copycode.gif]][copycode.gif 1]

如果只想让摄像头只能摄像,而不能拍照,那应该设置mediaTypes

cameraUI.mediaTypes = [[NSArray alloc] initWithObjects: (NSString *)  kUTTypeMovie  , nil];

kUTTypeImage 对应拍照

kUTTypeMovie  对应摄像

这要导入MobileCoreServices.framework,然后再

\#import <MobileCoreServices/UTCoreTypes.h>

然后就可以在一个触发事件中进行调用.

- (IBAction) showCameraUI {
        [self startCameraControllerFromViewController: self
                                        usingDelegate: self];
    }

2. 设置delegate

在拍摄完成后,要进行delegate的设置,这样才能够让程序互动起来.

[UIImagePickerControllerDelegate][]在方法主要有两个,

- (void) imagePickerControllerDidCancel: (UIImagePickerController *) picker ; 点击cancel后执行的方法

<table style="margin:0px; padding:0px 0px 4px; border-collapse:collapse; border-spacing:0px; border:1px solid rgb(199,207,213); width:978px; background-color:rgb(241,245,249); color:rgb(0,0,0); font-family:'Lucida Grande',Geneva,Helvetica,Arial,sans-serif; font-size:12px"> 
 <tbody style="margin:0px; padding:0px"> 
  <tr style="margin:0px; padding:0px; border-bottom-width:0px; border-bottom-style:solid; border-bottom-color:rgb(255,255,255)"> 
   <td style="margin:0px; padding:0.5em; border:1px solid rgb(192,192,192); border-collapse:collapse; word-break:normal!important"> <pre style="white-space:pre-wrap; word-wrap:break-word; margin-top:0px; margin-bottom:0px; padding:0px">- (void) imagePickerController: (UIImagePickerController *) picker</pre> </td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border-bottom-width:0px; border-bottom-style:solid; border-bottom-color:rgb(255,255,255)"> 
   <td style="margin:0px; padding:0.5em; border:1px solid rgb(192,192,192); border-collapse:collapse; word-break:normal!important"> <pre style="white-space:pre-wrap; word-wrap:break-word; margin-top:0px; margin-bottom:0px; padding:0px">            didFinishPickingMediaWithInfo: (NSDictionary *) info; 拍摄完成后要执行的方法</pre> </td> 
  </tr> 
 </tbody> 
</table>

code:

[![复制代码][copycode.gif]][copycode.gif 1]

// For responding to the user tapping Cancel.
    - (void) imagePickerControllerDidCancel: (UIImagePickerController *) picker {
     
        [[picker parentViewController] dismissModalViewControllerAnimated: YES];
        [picker release];
    }
     
     
     
     
    // For responding to the user accepting a newly-captured picture or movie
    - (void) imagePickerController: (UIImagePickerController *) picker
                didFinishPickingMediaWithInfo: (NSDictionary *) info {
     
        NSString *mediaType = [info objectForKey: UIImagePickerControllerMediaType];
        UIImage *originalImage, *editedImage, *imageToSave;
     
        // Handle a still image capture
        if (CFStringCompare ((CFStringRef) mediaType, kUTTypeImage, 0)
                == kCFCompareEqualTo) {
     
            editedImage = (UIImage *) [info objectForKey:
                        UIImagePickerControllerEditedImage];
            originalImage = (UIImage *) [info objectForKey:
                        UIImagePickerControllerOriginalImage];
     
            if (editedImage) {
                imageToSave = editedImage;
            } else {
                imageToSave = originalImage;
            }
     
        // Save the new image (original or edited) to the Camera Roll
            UIImageWriteToSavedPhotosAlbum (imageToSave, nil, nil , nil);
        }
     
        // Handle a movie capture
        if (CFStringCompare ((CFStringRef) mediaType, kUTTypeMovie, 0)
                == kCFCompareEqualTo) {
     
            NSString *moviePath = [[info objectForKey:
                        UIImagePickerControllerMediaURL] path];
     
            if (UIVideoAtPathIsCompatibleWithSavedPhotosAlbum (moviePath)) {
                UISaveVideoAtPathToSavedPhotosAlbum (
                        moviePath, nil, nil, nil);
            }
        }
     
        [[picker parentViewController] dismissModalViewControllerAnimated: YES];
        [picker release];
    }

[![复制代码][copycode.gif]][copycode.gif 1]

二. 从图片库中选择图片

在选择图片中,ipad 与iphone 会有些不同, ipad展示图片展时,必须要以popover的形式展示,如果想打开一个页面,来modal展示的话,会抛出异常.

这里要设置的属性只要是将

source type改为 UIImagePickerControllerSourceTypePhotoLibrary 或UIImagePickerControllerSourceTypeSavedPhotosAlbum,这个是根据自己选择来定.

mediatype的设置与上面的拍照一样.

代码:

如果是iPhone,则代码与上面拍照的一样,只要改下source type就可以了.但如果是ipad,会有所不同,下面的代码就是ipad为例.

在interface中:

@property (strong,nonatomic) UIPopoverController \* popoverViewControl;

在implement中:

[![复制代码][copycode.gif]][copycode.gif 1]

- (IBAction)takeImage:(id)sender {
        if ([self.popoverViewControl isPopoverVisible])
        {
            [self.popoverViewControl dismissPopoverAnimated:YES];
        }else {
            if ([UIImagePickerController isSourceTypeAvailable:
                 UIImagePickerControllerSourceTypeSavedPhotosAlbum])
            {
                UIImagePickerController * picker = [[UIImagePickerController alloc] init];
                picker.delegate = self;
                picker.allowsEditing = NO;
                picker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
              //  picker.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypeSavedPhotosAlbum];
                picker.mediaTypes = [[NSArray alloc] initWithObjects:(NSString *)  kUTTypeMovie , nil];
                self.popoverViewControl = [[UIPopoverControlleralloc] initWithContentViewController:picker];
                self.popoverViewControl.delegate = self;
                
                CGRect popoverRect = [self.view convertRect:[sender frame] 
                                                   fromView:[sender superview]];  
                popoverRect.size.width = MIN(popoverRect.size.width, 100);
                [self.popoverViewControl presentPopoverFromRect:popoverRect inView:self.view             permittedArrowDirections:UIPopoverArrowDirectionAnyanimated:YES];
            }
         }
    }
     
    - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
    {
        self.imageView.image = [info objectForKey:UIImagePickerControllerOriginalImage];    //imageview是自己定义的一个image view 控件,用来显示选中的图片
        [self.popoverViewControldismissPopoverAnimated:YES];
    }

[![复制代码][copycode.gif]][copycode.gif 1]

以上就是[UIImagePickerController][]的大概用法,主要就是自己看了apple的官方文档,然后实践后,记录下来,留用,防止忘了.

[UIImagePickerController]: http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIImagePickerController_Class/UIImagePickerController/UIImagePickerController.html
[AV Foundation framework]: http://developer.apple.com/library/ios/documentation/AudioVideo/Conceptual/AVFoundationPG/Articles/00_Introduction.html#//apple_ref/doc/uid/TP40010188
[Link 1]: http://developer.apple.com/library/ios/documentation/General/Reference/InfoPlistKeyReference/Articles/iPhoneOSKeys.html#//apple_ref/doc/uid/TP40009252-SW3
[isSourceTypeAvailable]: http://developer.apple.com/library/ios/documentation/UIKit/Reference/UIImagePickerController_Class/UIImagePickerController/UIImagePickerController.html#//apple_ref/occ/clm/UIImagePickerController/isSourceTypeAvailable:
[UIImagePickerControllerDelegate]: http://developer.apple.com/library/ios/#DOCUMENTATION/UIKit/Reference/UIImagePickerControllerDelegate_Protocol/UIImagePickerControllerDelegate/UIImagePickerControllerDelegate.html
[copycode.gif]: http://common.cnblogs.com/images/copycode.gif
[copycode.gif 1]: /images/20220810/c2ef65e4ccb8490e88834521dafd000c.png