ios 调用系统照片库/拍照/录像

在iOS中要拍照和录制视频最简单的方法就是使用UIImagePickerController。UIImagePickerController继承于UINavigationController，我们可以用它来选取照片,还可以用来拍照和录制视频。

要用UIImagePickerController来拍照或者录制视频通常可以分为如下步骤：

1. 创建UIImagePickerController对象。
2. 指定拾取源，平时选择照片时使用的拾取源是照片库或者相簿，此刻需要指定为摄像头类型。
3. 指定摄像头，前置摄像头或者后置摄像头。
4. 设置媒体类型mediaType，注意如果是录像必须设置，如果是拍照此步骤可以省略，因为mediaType默认包含kUTTypeImage（注意媒体类型定义在MobileCoreServices.framework中）
5. 指定捕获模式，拍照或者录制视频。（视频录制时必须先设置媒体类型再设置捕获模式）
6. 展示UIImagePickerController(通常以模态窗口形式打开）。
7. 拍照和录制视频结束后在代理方法中展示/保存照片或视频。

当然这个过程中有很多细节可以设置，例如是否显示拍照控制面板，拍照后是否允许编辑等等，通过上面的属性/方法列表相信并不难理解。

下面用代码来展示下UIImagePickerController的使用:

MyViewController

.h

#import "GetFilePath.h"

@interface MyViewController () <UINavigationControllerDelegate, UIImagePickerControllerDelegate>
@end

@implementation MyViewController
//触发事件：拍照
- (void)addCamera
{
    UIImagePickerController *picker = [[UIImagePickerController alloc] init];
    picker.delegate = self;
    picker.allowsEditing = YES; //可编辑
    //判断是否可以打开照相机
    if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
        //摄像头
        //UIImagePickerControllerSourceTypeSavedPhotosAlbum:相机胶卷
        picker.sourceType = UIImagePickerControllerSourceTypeCamera;
    } else { //否则打开照片库
        picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    }
    [self presentViewController:picker animated:YES completion:nil];
}

//触发事件：录像
- (void)addVideo
{
    UIImagePickerController *picker = [[UIImagePickerController alloc] init];
    picker.delegate = self;
    picker.allowsEditing = YES;
    if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
        picker.sourceType = UIImagePickerControllerSourceTypeCamera;
        picker.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];
        picker.videoQuality = UIImagePickerControllerQualityTypeMedium; //录像质量
        picker.videoMaximumDuration = 600.0f; //录像最长时间
        picker.mediaTypes = [NSArray arrayWithObjects:@"public.movie", nil];
    } else {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"温馨提示" message:@"当前设备不支持录像功能" delegate:self cancelButtonTitle:@"确定" otherButtonTitles:nil];
        [alert show];
    }
    //跳转到拍摄页面
    [self presentViewController:picker animated:YES completion:nil];
}

#pragma mark - UIImagePickerControllerDelegate

 //拍摄完成后要执行的代理方法
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
    BOOL success;
    NSFileManager *fileManager = [NSFileManager defaultManager];
    if ([mediaType isEqualToString:@"public.image"]) {
        //得到照片
        UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
        if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
            //图片存入相册
            UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
        }
        
        NSString *imagePath = [GetFilePath getSavePathWithFileSuffix:@"png"];
        success = [fileManager fileExistsAtPath:imagePath];
        if (success) {
            [fileManager removeItemAtPath:imagePath error:nil];
        }
        
        NSData *imageData = UIImagePNGRepresentation(image);
        [imageData writeToFile:imagePath atomically:YES]; //写入本地
        success = [fileManager fileExistsAtPath:imagePath];
        if (success) {
             NSLog(@"图片写入成功,image路径:%@",imagePath);
        }
    } else if ([mediaType isEqualToString:@"public.movie"]) {
        NSString *videoPath = [GetFilePath getSavePathWithFileSuffix:@"mov"];
        success = [fileManager fileExistsAtPath:videoPath];
        if (success) {
            [fileManager removeItemAtPath:videoPath error:nil];
        }
        
        NSURL *videoURL = [info objectForKey:UIImagePickerControllerMediaURL];
        NSData *videlData = [NSData dataWithContentsOfURL:videoURL];
        [videlData writeToFile:videoPath atomically:YES]; //写入本地
        //存储数据
        success = [fileManager fileExistsAtPath:videoPath];
        if (success) {
            NSLog(@"media 写入成功,video路径:%@",videoPath);
        }
    }
    [self dismissViewControllerAnimated:YES completion:nil];
}

//进入拍摄页面点击取消按钮
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
    [self dismissViewControllerAnimated:YES completion:nil];
}

GetFilePath

.h

#import <Foundation/Foundation.h>

@interface GetFilePath : NSObject

//获取要保存的本地文件路径
+ (NSString *)getSavePathWithFileSuffix:(NSString *)suffix;
//获取录像的缩略图
+ (UIImage *)getVideoThumbnailWithFilePath:(NSString *)filePath;
+ (UIImage *)getImage:(NSString *)filePath;


@end

.m

#import "GetFilePath.h"
#import <MediaPlayer/MediaPlayer.h>
#import <AVFoundation/AVFoundation.h>

@implementation GetFilePath

+ (NSString *)getSavePathWithFileSuffix:(NSString *)suffix
{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentPath = [paths objectAtIndex:0];
    
    NSDate *date = [NSDate date];
    //获取当前时间
    NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
    [dateFormat setDateFormat:@"yyyyMMddHHmmss"];
    NSString *curretDateAndTime = [dateFormat stringFromDate:date];
    //获取用户userID
    NSDictionary *userDic= [[NSUserDefaults standardUserDefaults] objectForKey:UserInformation];
    //命名文件
    NSString *fileName = [NSString stringWithFormat:@"%@%@.%@",userDic[@"UserID"],curretDateAndTime,suffix];
    //指定文件存储路径
    NSString *filePath = [documentPath stringByAppendingPathComponent:fileName];
    
    return filePath;
}

+ (UIImage *)getVideoThumbnailWithFilePath:(NSString *)filePath
{
    MPMoviePlayerController *moviePlayer = [[MPMoviePlayerController alloc] initWithContentURL:[NSURL fileURLWithPath:filePath]];
    moviePlayer.shouldAutoplay = NO;
    UIImage *image = [moviePlayer thumbnailImageAtTime:1.0 timeOption:MPMovieTimeOptionNearestKeyFrame];
    return image;
}

+ (UIImage *)getImage:(NSString *)filePath
{
    NSDictionary *options = [NSDictionary dictionaryWithObject:[NSNumber numberWithBool:NO] forKey:AVURLAssetPreferPreciseDurationAndTimingKey];
    NSURL *url = [NSURL fileURLWithPath:filePath];
    AVURLAsset *urlAsset = [[AVURLAsset alloc] initWithURL:url options:options];
    AVAssetImageGenerator *generator = [AVAssetImageGenerator assetImageGeneratorWithAsset:urlAsset];
    generator.appliesPreferredTrackTransform = YES;
    generator.maximumSize = CGSizeMake(60, 60);
    CGImageRef imageRef = [generator copyCGImageAtTime:CMTimeMake(10, 10) actualTime:NULL error:nil];
    UIImage *image = [UIImage imageWithCGImage:imageRef];
    return image;
}