问题
Here is my actual code below. It always downloads the first image fine, but gives "Camera is busy or the command is not supported in the camera's current state". I tried with the solution proposed by How to programmatically download Images from drone using the IOS DJI-SDK
I have been struggling with this for the past 10 days and tried all sorts of combination with triggering in async queue etc. but no success. Though DJI samples have a lot of code, they all focus on single download and preview etc. but not the entire raw data with multiple file downloads. Greatly appreciate any help.
func downLoad(){
guard let drone = (DJISDKManager.product() as? DJIAircraft) else {
testAlert(viewC: self, title: "Message", msg: "Unable to detect Drone", buttonText: "Dismiss")
return
}
// Get camera on drone
guard let camera: DJICamera = drone.camera else {
testAlert(viewC: self, title: "Message", msg: "Unable to detect Camera in initDownload()", buttonText: "Dismiss")
return
}
// check if we can download images with the product
if !camera.isMediaDownloadModeSupported() {
testAlert(viewC: self, title: "Message", msg: "Product does not support media download mode", buttonText: "Dismiss")
return
}
camera.setMode( .mediaDownload, withCompletion: {(error) in
if error != nil {
self.testAlert(viewC: self, title: "Message", msg: "Error \(error!.localizedDescription)", buttonText: "Dismiss")
} else {
// get the media manager from the drone to gain access to the files
let manager = camera.mediaManager!
manager.refreshFileList(of: DJICameraStorageLocation.sdCard, withCompletion: { (error) in
if error != nil {
Error here after first download
self.testAlert(viewC: self, title: "Message", msg: "Error refreshing list: \(error!.localizedDescription)", buttonText: "Dismiss")
}else {
// get list of files
guard let files = manager.sdCardFileListSnapshot() else {
self.testAlert(viewC: self, title: "Message", msg: "No files to download", buttonText: "Dismiss")
return
}
self.downloadImages(files: files, completion: { images in
//process images
self.testAlert(viewC: self, title: "Message", msg: "Successfully downloaded all images and count \(images.count)", buttonText: "Dismiss")
})//end of downloadImages
}// end of else
}) // end of file-refresh block
} // end of if else
})// end of camera setMode block
}
func downloadImages(files: [DJIMediaFile], completion: @escaping ([String]) -> Void){
func downloadNextImage( files: [DJIMediaFile], index: Int = 0, downloadedFileUrls: [String] = []) {
// stop when we reach the end of the list
if (index >= files.count - 1) {
completion(downloadedFileUrls)
return
}
else {
var imageData = Data()
var file = files[index]
let isPhoto = file.mediaType == DJIMediaType.JPEG || file.mediaType == DJIMediaType.TIFF;
var previousOffset: UInt = 0
file.fetchData(withOffset: previousOffset, update: DispatchQueue.main, update: {(_ data: Data?, _ isComplete: Bool, _ error: Error?) -> Void in
if let error = error {
self.testAlert(viewC: self, title: "Error", msg: "File index : \(index) previousOffset : \(previousOffset) name: \(file.fileName) error : \(error)", buttonText: "Dismiss")
}
else {
imageData.append(data!)
previousOffset = previousOffset + UInt((data?.count)!);
if isComplete {
if let image = UIImage(data: imageData) {
var imageUrl : String = ""
if(isPhoto){
imageUrl = saveFile(imag)
}else //video
{
//process video
}
downloadNextImage( files: files, index: (index + 1), downloadedFileUrls: downloadedFileUrls + [imageUrl])
}// If image
} //If complete
}// no eroor
}) // end of filedata fetch
} // end of else statement
}
// start the recursive function
downloadNextImage( files: files, index: 0)
}
来源：https://stackoverflow.com/questions/52784128/dji-ios-sdk-downloading-multiple-images-programatically-camera-busy-after-first