Flutter image_picker 选择视频

Question

我成功地使用 Flutter 插件 Image_picker 选择图像，以便我可以将它们用于上传、显示等......我想知道是否有人对如何修改此插件有任何指导也可以看到视频并允许他们被选择并用于上传等...

如果有人对如何继续或示例代码有指导，请寻找 iOS 和 Android 修改。我取得了一些进展，但仍然需要让相机保存视频并能够呈现。到目前为止，我将发布代码更改。我让它选择了一个视频，但它不会返回给应用程序。

// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

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

#import "ImagePickerPlugin.h"

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

static const int SOURCE_ASK_USER = 0;
static const int SOURCE_CAMERA = 1;
static const int SOURCE_GALLERY = 2;

@implementation ImagePickerPlugin {
  FlutterResult _result;
  NSDictionary *_arguments;
  UIImagePickerController *_imagePickerController;
  UIViewController *_viewController;
}

+ (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
  FlutterMethodChannel *channel =
      [FlutterMethodChannel methodChannelWithName:@"image_picker"
                                  binaryMessenger:[registrar messenger]];
  UIViewController *viewController =
      [UIApplication sharedApplication].delegate.window.rootViewController;
  ImagePickerPlugin *instance = [[ImagePickerPlugin alloc] initWithViewController:viewController];
  [registrar addMethodCallDelegate:instance channel:channel];
}

- (instancetype)initWithViewController:(UIViewController *)viewController {
  self = [super init];
  if (self) {
    _viewController = viewController;
    _imagePickerController = [[UIImagePickerController alloc] init];
  }
  return self;
}

- (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result {
  if (_result) {
    _result([FlutterError errorWithCode:@"multiple_request"
                                message:@"Cancelled by a second request"
                                details:nil]);
    _result = nil;
  }

  if ([@"pickImage" isEqualToString:call.method]) {
    _imagePickerController.modalPresentationStyle = UIModalPresentationCurrentContext;
    _imagePickerController.delegate = self;

    _result = result;
    _arguments = call.arguments;

    int imageSource = [[_arguments objectForKey:@"source"] intValue];

    switch (imageSource) {
      case SOURCE_ASK_USER:
        [self showImageSourceSelector];
        break;
      case SOURCE_CAMERA:
        [self showCamera];
        break;
      case SOURCE_GALLERY:
        [self showPhotoLibrary];
        break;
      default:
        result([FlutterError errorWithCode:@"invalid_source"
                                   message:@"Invalid image source."
                                   details:nil]);
        break;
    }
  } else {
    result(FlutterMethodNotImplemented);
  }
}

- (void)showImageSourceSelector {
  UIAlertControllerStyle style = UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad
                                     ? UIAlertControllerStyleAlert
                                     : UIAlertControllerStyleActionSheet;

  UIAlertController *alert =
      [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:style];
  UIAlertAction *camera = [UIAlertAction actionWithTitle:@"Take Photo"
                                                   style:UIAlertActionStyleDefault
                                                 handler:^(UIAlertAction *action) {
                                                   [self showCamera];
                                                 }];
  UIAlertAction *library = [UIAlertAction actionWithTitle:@"Choose Photo"
                                                    style:UIAlertActionStyleDefault
                                                  handler:^(UIAlertAction *action) {
                                                    [self showPhotoLibrary];
                                                  }];


  UIAlertAction *cancel =
      [UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleCancel handler:nil];
  [alert addAction:camera];
  [alert addAction:library];
  [alert addAction:cancel];
  [_viewController presentViewController:alert animated:YES completion:nil];
}

- (void)showCamera {
  // Camera is not available on simulators
  if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
    _imagePickerController.sourceType = UIImagePickerControllerCameraCaptureModeVideo;
    [_viewController presentViewController:_imagePickerController animated:YES completion:nil];
  } else {
    [[[UIAlertView alloc] initWithTitle:@"Error"
                                message:@"Camera not available."
                               delegate:nil
                      cancelButtonTitle:@"OK"
                      otherButtonTitles:nil] show];
  }
}

- (void)showPhotoLibrary {
  // No need to check if SourceType is available. It always is.
  //_imagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    _imagePickerController.mediaTypes =[UIImagePickerController availableMediaTypesForSourceType:_imagePickerController.sourceType];
  [_viewController presentViewController:_imagePickerController animated:YES completion:nil];
}

- (void)imagePickerController:(UIImagePickerController *)picker
    didFinishPickingMediaWithInfo:(NSDictionary<NSString *, id> *)info {
  [_imagePickerController dismissViewControllerAnimated:YES completion:nil];
  UIImage *image = [info objectForKey:UIImagePickerControllerEditedImage];
  NSURL *videoURL = [info objectForKey:UIImagePickerControllerMediaURL];
  if (image == nil) {
    image = [info objectForKey:UIImagePickerControllerOriginalImage];
  } else {
      image = [self normalizedImage:image];
  }
  if (videoURL == nil) {

  } else {
      //image = videoURL;
  }


  NSNumber *maxWidth = [_arguments objectForKey:@"maxWidth"];
  NSNumber *maxHeight = [_arguments objectForKey:@"maxHeight"];

  if (maxWidth != (id)[NSNull null] || maxHeight != (id)[NSNull null]) {
    image = [self scaledImage:image maxWidth:maxWidth maxHeight:maxHeight];
  }

  NSData *data = UIImageJPEGRepresentation(image, 1.0);
  NSString *tmpDirectory = NSTemporaryDirectory();
  NSString *guid = [[NSProcessInfo processInfo] globallyUniqueString];
  // TODO(jackson): Using the cache directory might be better than temporary
  // directory.
  NSString *tmpFile = [NSString stringWithFormat:@"image_picker_%@.jpg", guid];
  NSString *tmpPath = [tmpDirectory stringByAppendingPathComponent:tmpFile];
  if ([[NSFileManager defaultManager] createFileAtPath:tmpPath contents:data attributes:nil]) {
    _result(tmpPath);
  } else {
    _result([FlutterError errorWithCode:@"create_error"
                                message:@"Temporary file could not be created"
                                details:nil]);
  }
  _result = nil;
  _arguments = nil;
}

// The way we save images to the tmp dir currently throws away all EXIF data
// (including the orientation of the image). That means, pics taken in portrait
// will not be orientated correctly as is. To avoid that, we rotate the actual
// image data.
// TODO(goderbauer): investigate how to preserve EXIF data.
- (UIImage *)normalizedImage:(UIImage *)image {
  if (image.imageOrientation == UIImageOrientationUp) return image;

  UIGraphicsBeginImageContextWithOptions(image.size, NO, image.scale);
  [image drawInRect:(CGRect){0, 0, image.size}];
  UIImage *normalizedImage = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();
  return normalizedImage;
}


- (UIImage *)scaledImage:(UIImage *)image
                maxWidth:(NSNumber *)maxWidth
               maxHeight:(NSNumber *)maxHeight {
  double originalWidth = image.size.width;
  double originalHeight = image.size.height;

  bool hasMaxWidth = maxWidth != (id)[NSNull null];
  bool hasMaxHeight = maxHeight != (id)[NSNull null];

  double width = hasMaxWidth ? MIN([maxWidth doubleValue], originalWidth) : originalWidth;
  double height = hasMaxHeight ? MIN([maxHeight doubleValue], originalHeight) : originalHeight;

  bool shouldDownscaleWidth = hasMaxWidth && [maxWidth doubleValue] < originalWidth;
  bool shouldDownscaleHeight = hasMaxHeight && [maxHeight doubleValue] < originalHeight;
  bool shouldDownscale = shouldDownscaleWidth || shouldDownscaleHeight;

  if (shouldDownscale) {
    double downscaledWidth = (height / originalHeight) * originalWidth;
    double downscaledHeight = (width / originalWidth) * originalHeight;

    if (width < height) {
      if (!hasMaxWidth) {
        width = downscaledWidth;
      } else {
        height = downscaledHeight;
      }
    } else if (height < width) {
      if (!hasMaxHeight) {
        height = downscaledHeight;
      } else {
        width = downscaledWidth;
      }
    } else {
      if (originalWidth < originalHeight) {
        width = downscaledWidth;
      } else if (originalHeight < originalWidth) {
        height = downscaledHeight;
      }
    }
  }

  UIGraphicsBeginImageContextWithOptions(CGSizeMake(width, height), NO, 1.0);
  [image drawInRect:CGRectMake(0, 0, width, height)];

  UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();

  return scaledImage;
}

@end

谢谢

Answer 1

这是我已经完成的 IOS 代码，如果有人想提供帮助，我仍在开发 Android，我会发布我目前的位置。此代码替换了 IOS 文件夹的 .m 文件中的内容，无需其他更改即可选择和捕获视频以及图像。您必须弄清楚如何在您的应用程序中显示选定的视频/图像，但这就是您想要处理的方式。如果您想协助完成 Android 方面的工作，请再次告诉我。

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

#import "MediaPickerPlugin.h"

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

static const int SOURCE_ASK_USER = 0;
//static const int SOURCE_CAMERA = 0;
//static const int SOURCE_GALLERY = 0;

@implementation MediaPickerPlugin {
    FlutterResult _result;
    NSDictionary *_arguments;
    UIImagePickerController *_imagePickerController;
    UIViewController *_viewController;
}

+ (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
    FlutterMethodChannel *channel =
    [FlutterMethodChannel methodChannelWithName:@"media_picker"
                                binaryMessenger:[registrar messenger]];
    UIViewController *viewController =
        [UIApplication sharedApplication].delegate.window.rootViewController;
    MediaPickerPlugin *instance =
        [[MediaPickerPlugin alloc] initWithViewController:viewController];
    [registrar addMethodCallDelegate:instance channel:channel];
}

- (instancetype)initWithViewController:(UIViewController *)viewController {
    self = [super init];
    if (self) {
      _viewController = viewController;
      _imagePickerController = [[UIImagePickerController alloc] init];
    }
    return self;
}

- (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result {
  if (_result) {
    _result([FlutterError errorWithCode:@"multiple_request"
                                message:@"Cancelled by a second request"
                                details:nil]);
    _result = nil;
      _arguments = nil;
}

if ([@"pickImage" isEqualToString:call.method]) {
  _imagePickerController.modalPresentationStyle = UIModalPresentationCurrentContext;
  _imagePickerController.delegate = self;

  _result = result;
  _arguments = call.arguments;

  int imageSource = [[_arguments objectForKey:@"source"] intValue];

    switch (imageSource) {
        case SOURCE_ASK_USER:
            [self showImageSourceSelector];
            break;
        default:
            result([FlutterError errorWithCode:@"invalid_source"
                                       message:@"Invalid image source."
                                       details:nil]);
            break;
        }
    } else {
      result(FlutterMethodNotImplemented);
    }
}

- (void)showImageSourceSelector {
    UIAlertControllerStyle style = UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad
                                        ? UIAlertControllerStyleAlert
                                        : UIAlertControllerStyleActionSheet;

    UIAlertController *alert =
        [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:style];
    UIAlertAction *camera = [UIAlertAction actionWithTitle:@"Camera"
                                                     style:UIAlertActionStyleDefault
                                                   handler:^(UIAlertAction *action) {
                                                       [self showCamera];
                                                   }];
    UIAlertAction *library = [UIAlertAction actionWithTitle:@"Gallery"
                                                      style:UIAlertActionStyleDefault
                                                    handler:^(UIAlertAction *action) {
                                                        [self showPhotoLibrary];
                                                    }];
    UIAlertAction *cancel =
    [UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleCancel handler:nil];
    [alert addAction:camera];
    [alert addAction:library];
    [alert addAction:cancel];
    [_viewController presentViewController:alert animated:YES completion:nil];
}

- (void)showCamera {
    // Camera is not available on simulators
    if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
        _imagePickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
        _imagePickerController.mediaTypes = [NSArray arrayWithObjects:@"public.movie", @"public.image", nil];
        _imagePickerController.delegate = self;
        _imagePickerController.restoresFocusAfterTransition = false;
        _imagePickerController.allowsEditing = NO;
        _imagePickerController.videoQuality = UIImagePickerControllerQualityTypeLow;
        _imagePickerController.videoMaximumDuration = 30.0f; // 30 seconds
        [_viewController presentViewController:_imagePickerController animated:YES completion:nil];
    } else {
        [[[UIAlertView alloc] initWithTitle:@"Error"
                                    message:@"Camera not available."
                                   delegate:nil
                          cancelButtonTitle:@"OK"
                          otherButtonTitles:nil] show];
    }
}

- (void)showPhotoLibrary {
// No need to check if SourceType is available. It always is.
_imagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    _imagePickerController.mediaTypes = [NSArray arrayWithObjects:@"public.movie", @"public.image", nil];
//_imagePickerController.mediaTypes =[UIImagePickerController availableMediaTypesForSourceType:_imagePickerController.sourceType];
[_viewController presentViewController:_imagePickerController animated:YES completion:nil];
}

- (void)imagePickerController:(UIImagePickerController *)picker
      didFinishPickingMediaWithInfo:(NSDictionary<NSString *, id> *)info {
  [_imagePickerController dismissViewControllerAnimated:YES completion:nil];
  NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
  if ([mediaType isEqualToString:@"public.movie"]) {
    NSURL *videoURL = [info objectForKey:UIImagePickerControllerMediaURL];
    NSString *videoString = [videoURL absoluteString];
    NSLog(@"Video File:%@", videoString);
    _result(videoString);
  } else {
    UIImage *image = [info objectForKey:UIImagePickerControllerEditedImage];
    if (image == nil) {
      image = [info objectForKey:UIImagePickerControllerOriginalImage];
    }
    image = [self normalizedImage:image];

    NSNumber *maxWidth = [_arguments objectForKey:@"maxWidth"];
    NSNumber *maxHeight = [_arguments objectForKey:@"maxHeight"];

    if (maxWidth != (id)[NSNull null] || maxHeight != (id)[NSNull null]) {
      image = [self scaledImage:image maxWidth:maxWidth maxHeight:maxHeight];
    }

    NSData *data = UIImageJPEGRepresentation(image, 1.0);
    NSString *tmpDirectory = NSTemporaryDirectory();
    NSString *guid = [[NSProcessInfo processInfo] globallyUniqueString];
    // TODO(jackson): Using the cache directory might be better than temporary
    // directory.
    NSString *tmpFile = [NSString stringWithFormat:@"image_picker_%@.jpg", guid];
    NSString *tmpPath = [tmpDirectory stringByAppendingPathComponent:tmpFile];
    NSLog(@"Image File:%@", tmpPath);
    if ([[NSFileManager defaultManager] createFileAtPath:tmpPath contents:data attributes:nil]) {
        _result(tmpPath);
    } else {
        _result([FlutterError errorWithCode:@"create_error"
                                    message:@"Temporary file could not be created"
                                    details:nil]);
    }
      _result = nil;
      _arguments = nil;
  }
  _result = nil;
  _arguments = nil;
}

// The way we save images to the tmp dir currently throws away all EXIF data
    // (including the orientation of the image). That means, pics taken in portrait
    // will not be orientated correctly as is. To avoid that, we rotate the actual
    // image data.
// TODO(goderbauer): investigate how to preserve EXIF data.
- (UIImage *)normalizedImage:(UIImage *)image {
    if (image.imageOrientation == UIImageOrientationUp) return image;

    UIGraphicsBeginImageContextWithOptions(image.size, NO, image.scale);
    [image drawInRect:(CGRect){0, 0, image.size}];
    UIImage *normalizedImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return normalizedImage;
}
//- (NSString *)normalVideo:(NSURL *)videoURL {
  //    NSString *normalVideo = UIImagePickerControllerMediaURL;
  //    return normalVideo;
//}

- (UIImage *)scaledImage:(UIImage *)image
    maxWidth:(NSNumber *)maxWidth
    maxHeight:(NSNumber *)maxHeight {
    double originalWidth = image.size.width;
    double originalHeight = image.size.height;

    bool hasMaxWidth = maxWidth != (id)[NSNull null];
    bool hasMaxHeight = maxHeight != (id)[NSNull null];

    double width = hasMaxWidth ? MIN([maxWidth doubleValue], originalWidth) : originalWidth;
    double height = hasMaxHeight ? MIN([maxHeight doubleValue], originalHeight) : originalHeight;

    bool shouldDownscaleWidth = hasMaxWidth && [maxWidth doubleValue] < originalWidth;
    bool shouldDownscaleHeight = hasMaxHeight && [maxHeight doubleValue] < originalHeight;
    bool shouldDownscale = shouldDownscaleWidth || shouldDownscaleHeight;

    if (shouldDownscale) {
          double downscaledWidth = (height / originalHeight) * originalWidth;
          double downscaledHeight = (width / originalWidth) * originalHeight;

          if (width < height) {
            if (!hasMaxWidth) {
              width = downscaledWidth;
            } else {
              height = downscaledHeight;
            }
          } else if (height < width) {
            if (!hasMaxHeight) {
              height = downscaledHeight;
            } else {
              width = downscaledWidth;
            }
          } else {
            if (originalWidth < originalHeight) {
              width = downscaledWidth;
            } else if (originalHeight < originalWidth) {
              height = downscaledHeight;
            }
          }
    }

    UIGraphicsBeginImageContextWithOptions(CGSizeMake(width, height), NO, 1.0);
    [image drawInRect:CGRectMake(0, 0, width, height)];

    UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return scaledImage;
}

@end