如何检测用户何时点击“录制” UIImagePickerController 中的按钮？

Question

我想在用户点击 UIImagePicker 控制器中的记录按钮时显示倒计时，但没有委托方法告诉我们他们何时点击记录。我可以设置最长持续时间，但我想给出 1 分钟警告或类似效果，但我不知道如何执行该

videoPickerCtrl = [[UIImagePickerController alloc] init];
videoPickerCtrl.delegate = self;
videoPickerCtrl.sourceType =      UIImagePickerControllerSourceTypeCamera;
videoPickerCtrl.mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:videoPickerCtrl.sourceType];   
videoPickerCtrl.allowsEditing = NO;
videoPickerCtrl.videoMaximumDuration = 170;
videoPickerCtrl.mediaTypes = [NSArray arrayWithObject:(NSString *)kUTTypeMovie];

操作编辑：

我找不到解决方案，所以我做了自己的自定义视频选择器控制器。希望其他人能发现它有用： https://github.com/saliksyed/CustomVideoCapture

Answer 1

在一个完美的世界中，你会希望苹果只提供几个代表来做这件事。例如：

• (void)imagePickerControllerDidStartVideoCapturing:(UIImagePickerController *)picker
• (void)imagePickerControllerDidStopVideoCapturing:(UIImagePickerController *)picker

然而现实（根据苹果文档）是：

• UIImagePickerController 的协议太基础了，无法做到这一点
• 这个类旨在使用按原样并且不支持子类化
• 此类的视图层次结构是私有的，不得修改

文档还指出：“您可以将自定义视图分配给cameraOverlayView属性并使用该视图来呈现附加信息或管理相机接口和您的代码”。

在我的应用程序中，我需要呈现“UIProgressView”来指示视频可以录制多长时间。为了实现这一点，我需要能够检测视频捕捉开始的时刻。

我不想禁用本机相机控件，因为它们很酷，而且我很懒，所以我不想花太多时间重新发明轮子。我所需要的只是捕获一个大的红色按钮被点击以开始或停止录制的事实。

我的解决方案是用自定义视图“覆盖”原始的开始/停止录制按钮，并为该视图启用用户交互，如下所示：

overlayView = [[UIView alloc] initWithFrame:self.view.frame];

// Start/ Stop fake button
UIView *ssView = [[UIView alloc] initWithFrame:CGRectMake(self.view.frame.size.width / 2 - 35, self.view.frame.size.height - 71, 70, 70)];
[ssView setUserInteractionEnabled:YES];

// Background color below is only there to make sure my pseudo-button overlaps native Start/Stop button. Comment out the line below to leave it transparent
[ssView setBackgroundColor:[UIColor colorWithRed:0 green:1 blue:0 alpha:0.5f]];

UITapGestureRecognizer *t = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapped:)];
[ssView addGestureRecognizer:t];

[overlayView addSubview:ssView];  

// My own progress bar
UIProgressView *p = [[UIProgressView alloc] initWithProgressViewStyle:UIProgressViewStyleDefault];
[p setTintColor:[UIColor redColor]];
[p setCenter:CGPointMake(30, 130)];
[p setTransform:CGAffineTransformMakeRotation( M_PI / 2 )];
[p setProgress:0];

[overlayView addSubview:p];

pickerController.cameraOverlayView = overlayView;

然后我为点击定义了事件处理程序，如下所示：

-(void)tapped:(id)sender {

    if (isRecording) {
        [pickerController stopVideoCapture];
        NSLog(@"Video capturing stopped...");
        // add your business logic here ie stop updating progress bar etc...
        [pickerController.cameraOverlayView setHidden:YES];
        isRecording = NO;
        return;
    }

    if ([pickerController startVideoCapture]) {
        NSLog(@"Video capturing started...");
        // add your business logic here ie start updating progress bar etc...
        isRecording = YES;
    }

}

接口文件的完整代码：

#import <UIKit/UIKit.h>
#import <MobileCoreServices/MobileCoreServices.h>

@interface ViewController : UIViewController <UIImagePickerControllerDelegate>
- (IBAction)openCamera:(id)sender;

@end

实现文件：

#import "ViewController.h"

@interface ViewController () {
    UIImagePickerController *pickerController;
    UIView* overlayView;
    BOOL isRecording;
}

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    isRecording = NO;

    pickerController = [[UIImagePickerController alloc] init];
    pickerController.delegate = self;
    pickerController.allowsEditing = NO;
    pickerController.videoMaximumDuration = 30.0f;
    pickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
    pickerController.mediaTypes = [[NSArray alloc] initWithObjects: (NSString *) kUTTypeMovie, nil];

    // I want default controls be available here...
    pickerController.showsCameraControls = YES;

    overlayView = [[UIView alloc] initWithFrame:self.view.frame];

    // Start/ Stop fake button
    UIView *ssView = [[UIView alloc] initWithFrame:CGRectMake(self.view.frame.size.width / 2 - 35, self.view.frame.size.height - 71, 70, 70)];
    [ssView setUserInteractionEnabled:YES];
    // Background color below is only there to make sure myt pseudo-button overlaps native Start/Stop button
    [ssView setBackgroundColor:[UIColor colorWithRed:0 green:1 blue:0 alpha:0.5f]];

   UITapGestureRecognizer *t = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapped:)];
   [ssView addGestureRecognizer:t];

   [overlayView addSubview:ssView];

   // My own progress bar
   UIProgressView *p = [[UIProgressView alloc] initWithProgressViewStyle:UIProgressViewStyleDefault];
   [p setTintColor:[UIColor redColor]];
   [p setCenter:CGPointMake(30, 130)];
   [p setTransform:CGAffineTransformMakeRotation( M_PI / 2 )];
   [p setProgress:0];

   [overlayView addSubview:p];

   pickerController.cameraOverlayView = overlayView;

}

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {
    // Cancel button tapped
    [picker dismissViewControllerAnimated:YES completion:nil];
}

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

    NSLog(@"Got image : %@", info);
    [picker dismissViewControllerAnimated:YES completion:nil];

    // Do something with video captured
}

-(void)tapped:(id)sender {

    if (isRecording) {
        [pickerController stopVideoCapture];
        NSLog(@"Video capturing stopped...");
        // add your business logic here ie stop updating progress bar etc...
        [pickerController.cameraOverlayView setHidden:YES];
        isRecording = NO;
        return;
    }

    if ([pickerController startVideoCapture]) {
        NSLog(@"Video capturing started...");
        // add your business logic here ie start updating progress bar etc...
        isRecording = YES;
    }

}

- (IBAction)openCamera:(id)sender {
    [pickerController.cameraOverlayView setHidden:NO];
    [self presentViewController:pickerController animated:YES completion:nil];    
}
@end

您可能我注意到一旦视频捕捉停止我就会隐藏cameraOverlayView。

[pickerController.cameraOverlayView setHidden:YES];

这是为了允许“重新拍摄/播放和使用”本机控件在录制视频后正常工作。

Answer 2

当用户点击按钮时，您不会收到通知，但您可以提供自己的记录按钮：将图像选择器设置为隐藏其标准控件 (showsCameraControls) 并提供自定义叠加视图 (cameraOverlayView）。在该叠加视图中，放置一个连接到目标/操作的自定义按钮，并在操作方法中调用 -startVideoCapture。

Answer 3

好的。所以我很确定我想要实现的目标是不可能的。我将使用 AVFoundation 作为后端为视频重新创建标准 UIImagePickerController 接口。希望一旦完成我会将其发布到 github 或其他地方。

Answer 4

我通过使用自定义叠加视图创建了您正在寻找的相同效果。

您需要使用 UIVideoEditorController 实例创建一个模式窗口，其 videoPath 属性是 userInfo 中的 UIImagePickerControllerMediaURL 键您应该处理的 imagePickerController:didFinishPickingMediaWithInfo: 方法。

华泰

Answer 5

对于其他人来说，如果您在 UIImagePickerController 上使用自定义叠加视图，则可以完成此操作。只需将所需的所有控件添加到视图中，然后将该父视图设置为属性 cameraOverlayView 即可。