我成功地使用 Flutter 插件 Image_picker 来选择图片，以便用于上传、显示等等... 我想知道是否有人能够指导如何修改该插件，使其也能够查看视频并允许选择并用于上传等操作...
如果有人能够指导如何进行 iOS 和 Android 上的修改或提供示例代码，那就太好了。我已经取得了一些进展，但仍需要让相机保存视频并能够呈现出来。我将发布到目前为止的代码更改。我已经可以选择视频了，但无法在应用程序中显示。
// 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