目前，将视频捕获集成到你的应用中的最简单的方法是使用 UIImagePickerController。这是一个封装了完整视频捕获管线和相机 UI 的 view controller。用UIImagePickerController可以自定义系统提供的界面来拍摄并保存视频和照片。
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.
UIImagePickerControllerSourceTypeCamera: 提供调用摄像头的界面来拍摄照片视频。
UIImagePickerControllerSourceTypePhotoLibrary调用图片库作为UIImagePickerController数据源。
UIImagePickerControllerSourceTypeSavedPhotosAlbumiOS设备中的胶卷相机的图片.作为UIImagePickerController数据源Mediatypes:
NSArray数组。拍摄时：这个属性决定UIImagePickerController界面模式是拍照还是录像.查看已保存多媒体数据，可决定展示的是照片还是视频。
kUTTypeImage表示静态图片,kUTTypeMovie表示录像.把空数组传给这个属性会报异常。在设置此属性前，需要用availableMediaTypesForSourceType:类方法判断这种多媒体类型是否被支持。**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.delegate
id <UINavigationControllerDelegate, UIImagePickerControllerDelegate> delegate:
使用 UIImagePickerController，必须提供遵守UIImagePickerControllerDelegate和UINavigationControllerDelegate协议
的delegate对象.UIImagePickerControllerDelegate提供了两个方法来在照相完成后，与UIImagePickerController对象界面进行交互。
imagePickerController:didFinishPickingMediaWithInfo:delegate使用拍摄的照片或者视频的处理逻辑.
imagePickerControllerDidCancel(_:)取消picker view。
步骤
1.首先要检查设备是否支持相机录制, 否则设备不支持相机时，会crash 。
if ([UIImagePickerController
isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera] == NO) return;
UIImagePickerController *camera = [[UIImagePickerController alloc] init];
camera.sourceType = UIImagePickerControllerSourceTypeCamera;
2.检查在 source type中支持的多媒体类型,并设置mediatypes
camera.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];
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>
3.设置delegate，定义拍摄完成后的交互事件处理
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info
{
NSString *mediaType = [info objectForKey: UIImagePickerControllerMediaType];
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"选择视频" message:nil delegate:self cancelButtonTitle:@"好" otherButtonTitles:nil, nil];
[alertView show];
NSLog(@"didFinishPickingMediaWithInfo info=%@;type = %@", info, mediaType);
}
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
NSLog(@"imagePickerControllerDidCancel");
[picker dismissViewControllerAnimated:YES completion:nil];
}
完整代码：
ViewController.m
#import <MobileCoreServices/UTCoreTypes.h>
#import <MediaPlayer/MediaPlayer.h>
#import <AVFoundation/AVFoundation.h>
#import "ViewController.h"
@interface ViewController () <UINavigationControllerDelegate, UIImagePickerControllerDelegate, UIAlertViewDelegate>
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
UIBarButtonItem *rightItem = [[UIBarButtonItem alloc] initWithTitle:@"拍摄" style:UIBarButtonItemStylePlain target:self action:@selector(startCameraControllerFromViewController:)];
self.navigationItem.rightBarButtonItem = rightItem;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info
{
NSString *mediaType = [info objectForKey: UIImagePickerControllerMediaType];
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"选择视频" message:nil delegate:self cancelButtonTitle:@"好" otherButtonTitles:nil, nil];
[alertView show];
NSLog(@"didFinishPickingMediaWithInfo info=%@;type = %@", info, mediaType);
}
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
NSLog(@"imagePickerControllerDidCancel");
[picker dismissViewControllerAnimated:YES completion:nil];
}
// 设备是否被授权访问相机
-(BOOL)isCameraAuthorized
{
AVAuthorizationStatus auth = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];
return (auth == AVAuthorizationStatusAuthorized);
}
// 请访问求相机授权
- (void)requestCameraAuthorization
{
NSString *title = @"请在\设置-隐私-相机\"选项中，允许访问你的相机。";
AVAuthorizationStatus auth = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];
if (auth == AVAuthorizationStatusNotDetermined) {
[AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted) {
dispatch_async(dispatch_get_main_queue(), ^{
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:title message:nil delegate:self cancelButtonTitle:@"好" otherButtonTitles:nil];
[alertView show];
});
}];
}
else {
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:title message:nil delegate:self cancelButtonTitle:@"好" otherButtonTitles:nil];
[alertView show];
}
}
- (void)startCameraControllerFromViewController: (UIViewController*)controller
{
if (![self isCameraAuthorized]) {
[self requestCameraAuthorization];
}
if ([UIImagePickerController
isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera] == NO) return;
UIImagePickerController *camera = [[UIImagePickerController alloc] init];
camera.sourceType = UIImagePickerControllerSourceTypeCamera;
camera.delegate = self;
camera.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];
[self presentViewController:camera animated:YES completion:nil];
}
@end
AppDelegate.m
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Override point for customization after application launch.
self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
self.viewController = [[ViewController alloc] init];
self.navigationController = [[UINavigationController alloc] init];
[self.navigationController pushViewController:self.viewController animated:YES];
self.window.rootViewController = self.navigationController;
return YES;
}
bug：
横向拍摄视频，完成拍摄后点击“使用视频”，摄像头被打开，背景出现摄像流。
设备和系统：
iPhone6Plus 9.1 ，上述情况
iPhone5s 8.3 , 上述情况
iPhone4s 7.1.1, 上述情况，但是显示是已拍摄视频的最后一帧。
问题原因：
调用系统摄像机录像时,UIImagePickerController视图有两个关键子view，CMKVideoPreviewView和PLAVPlayerView。
PLAVPlayerView 用来播放已录制的视频。
CMKVideoPreviewView 负责展示摄像头实时拍摄的视频流。 PreviewView在不同系统版本有不同的名字：
- 9.1系统的类名是CMKVideoPreviewView;
- 8.3系统是CAMVideoPreviewView;
- 7.1系统是 PLVideoPreviewView）
视图层次结构：CMKVideoPreviewView在下，PLAVPlayerView 在上。横屏拍摄视频，完成拍摄后，由于UIImagePickerController官方只支持竖屏模式，系统自动转为竖屏模式并更新PLVideoPosterFrameView的UIImageView（已录制视频的快照）的frame为 (0, 212,75, 414, 310,5),所以原本被遮挡的CMKVideoPreviewView就显示出来了。
解决方案：
思路：在点击“使用视频”之后，弹出“压缩”toast提示之前，获取CMKVideoPreviewView对象的指针，并讲该对象的hidden属性设为YES.由于CMKVideoPreviewView是private frameworks中的类，无法直接获取对象，但可通过public api : view.subviews ,在子view中递归查找目标对象，安全地获取到该对象。此方法可以通过appstore的审查。 如何安全使用私有库类
- (void)setVideoPreviewHidden:(BOOL)hidden inPicker:(UIImagePickerController *)picker
{
UIView *view = nil;
float systemVersion = UIDevice.currentDevice.systemVersion.floatValue;
if (systemVersion>= 10.0) {
return;
}
else if (systemVersion>= 9.0) {
view = UIViewFindSubview(picker.view, [NSClassFromString(@"CMKVideoPreviewView") class]);
}
else if (systemVersion >= 8.0) {
view = UIViewFindSubview(picker.view, [NSClassFromString(@"CAMVideoPreviewView") class]);
}
else if (systemVersion >= 7.0) {
view = UIViewFindSubview(picker.view, [NSClassFromString(@"PLVideoPreviewView") class]);
}
view.hidden = hidden;
}
NS_INLINE UIView *UIViewFindSubview(UIView *view, Class viewClass)
{
for (UIView *subview in view.subviews) {
if ([subview isKindOfClass:viewClass]) {
return subview;
} else {
UIView *ret = UIViewFindSubview(subview, viewClass);
if (ret) return ret;
}
}
return nil;
}
