我对音乐文件有疑问。
我想从 iPhone/iTouch/iPad 的音乐库中选择 1 个/多个音乐文件并保存在我的文档文件夹中或发送到服务器。
我大致经历了MPMediaPickerController和AddMusic(Sample Code)。 但是，我只能获得选择歌曲和播放的详细信息。
是否可以保存那些选定的歌曲，我也可以用它来发送到服务器？
谢谢
【问题讨论】：
标签： objective-c ios mpmediaitem mpmediapickercontroller
是否可以保存那些选定的歌曲，我也可以用它们发送到服务器？
不，您只能播放 iTunes 资料库中的歌曲。
原始音频文件无法访问，可能是由于版权保护。
【讨论】：
是的，有可能。
我想对你有帮助
// Have to add this framework
//CoreMedia.framework
//AudioToolbox.framework
//CoreAudio.framework
//MediaPlayer.framework
//AVFoundation.framework
//in UploadAudioViewController.h file
#import <UIKit/UIKit.h>
#import <CoreAudio/CoreAudioTypes.h>
#import <AudioToolbox/AudioToolbox.h>
#import <MediaPlayer/MediaPlayer.h>
#import <AVFoundation/AVFoundation.h>
#import <CoreMedia/CoreMedia.h>
@interface UploadAudioViewController : UIViewController<UIActionSheetDelegate,UINavigationControllerDelegate,UIImagePickerControllerDelegate,MPMediaPickerControllerDelegate,AVAudioRecorderDelegate, AVAudioPlayerDelegate,AVAudioSessionDelegate>{
MPMediaItem *song;
NSURL *exportURL;
}
@property (nonatomic, retain) NSData *audioData;
// in UploadAudioViewController.m file
#import "UploadAudioViewController.h"
//#import < AudioToolbox/AudioToolbox.h>
@interface UploadAudioViewController ()
@end
@implementation UploadAudioViewController
@synthesize musicPlayer,audioData;
-(id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
-(void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
self.title = @"Upload Audio";
self.musicPlayer = [MPMusicPlayerController iPodMusicPlayer];
self.audioData=nil;
}
#pragma mark Browse Audio from Device
-(void)PickAudioForIndex_iPhone
{
if ([[[UIDevice currentDevice] model] isEqualToString:@"iPhone Simulator"]) {
//device is simulator
UIAlertView *alert1;
alert1 = [[UIAlertView alloc] initWithTitle:@"Alert" message:@"There is no Audio file in the Device" delegate:self cancelButtonTitle:nil otherButtonTitles:@"Ok",nil];
alert1.tag=2;
[alert1 show];
//[alert1 release],alert1=nil;
}else{
MPMediaPickerController *mediaPicker = [[MPMediaPickerController alloc] initWithMediaTypes:MPMediaTypeMusic];
mediaPicker.delegate = self;
mediaPicker.allowsPickingMultipleItems = NO; // this is the default
[self presentViewController:mediaPicker animated:YES completion:nil];
}
}
#pragma mark Media picker delegate methods
-(void)mediaPicker:(MPMediaPickerController *)mediaPicker didPickMediaItems:(MPMediaItemCollection *)mediaItemCollection {
// We need to dismiss the picker
[self dismissViewControllerAnimated:YES completion:nil];
// Assign the selected item(s) to the music player and start playback.
if ([mediaItemCollection count] < 1) {
return;
}
song = [[mediaItemCollection items] objectAtIndex:0];
[self handleExportTapped];
}
-(void)mediaPickerDidCancel:(MPMediaPickerController *)mediaPicker {
// User did not select anything
// We need to dismiss the picker
[self dismissViewControllerAnimated:YES completion:nil ];
}
-(void)handleExportTapped{
// get the special URL
if (! song) {
return;
}
//[self startLoaderWithLabel:@"Preparing for upload..."];
NSURL *assetURL = [song valueForProperty:MPMediaItemPropertyAssetURL];
AVURLAsset *songAsset = [AVURLAsset URLAssetWithURL:assetURL options:nil];
NSLog (@"Core Audio %@ directly open library URL %@",
coreAudioCanOpenURL (assetURL) ? @"can" : @"cannot",
assetURL);
NSLog (@"compatible presets for songAsset: %@",
[AVAssetExportSession exportPresetsCompatibleWithAsset:songAsset]);
/* approach 1: export just the song itself
*/
AVAssetExportSession *exporter = [[AVAssetExportSession alloc]
initWithAsset: songAsset
presetName: AVAssetExportPresetAppleM4A];
NSLog (@"created exporter. supportedFileTypes: %@", exporter.supportedFileTypes);
exporter.outputFileType = @"com.apple.m4a-audio";
NSString *exportFile = [myDocumentsDirectory() stringByAppendingPathComponent: @"exported.m4a"];
// end of approach 1
// set up export (hang on to exportURL so convert to PCM can find it)
myDeleteFile(exportFile);
//[exportURL release];
exportURL = [NSURL fileURLWithPath:exportFile];
exporter.outputURL = exportURL;
// do the export
[exporter exportAsynchronouslyWithCompletionHandler:^{
int exportStatus = exporter.status;
switch (exportStatus) {
case AVAssetExportSessionStatusFailed: {
// log error to text view
NSError *exportError = exporter.error;
NSLog (@"AVAssetExportSessionStatusFailed: %@", exportError);
//errorView.text = exportError ? [exportError description] : @"Unknown failure";
//errorView.hidden = NO;
//[self stopLoader];
//[self showAlertWithMessage:@"There ia an error!"];
break;
}
case AVAssetExportSessionStatusCompleted: {
NSLog (@"AVAssetExportSessionStatusCompleted");
//fileNameLabel.text = [exporter.outputURL lastPathComponent];
// set up AVPlayer
//[self setUpAVPlayerForURL: exporter.outputURL];
///////////////// get audio data from url
//[self stopLoader];
//[self showAlertWithMessage:@"There ia an error!"];
NSURL *audioUrl = exportURL;
NSLog(@"Audio Url=%@",audioUrl);
self.audioData = [NSData dataWithContentsOfURL:audioUrl];
break;
}
case AVAssetExportSessionStatusUnknown: {
NSLog (@"AVAssetExportSessionStatusUnknown");
//[self stopLoader];
//[self showAlertWithMessage:@"There ia an error!"];
break;
}
case AVAssetExportSessionStatusExporting: {
NSLog (@"AVAssetExportSessionStatusExporting");
//[self stopLoader];
//[self showAlertWithMessage:@"There ia an error!"];
break;
}
case AVAssetExportSessionStatusCancelled: {
NSLog (@"AVAssetExportSessionStatusCancelled");
//[self stopLoader];
//[self showAlertWithMessage:@"There ia an error!"];
break;
}
case AVAssetExportSessionStatusWaiting: {
NSLog (@"AVAssetExportSessionStatusWaiting");
//[self stopLoader];
//[self showAlertWithMessage:@"There ia an error!"];
break;
}
default: {
NSLog (@"didn't get export status");
//[self stopLoader];
//[self showAlertWithMessage:@"There ia an error!"];
break;
}
}
}];
}
#pragma mark conveniences
NSString* myDocumentsDirectory(){
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
return [paths objectAtIndex:0];;
}
void myDeleteFile (NSString* path){
if ([[NSFileManager defaultManager] fileExistsAtPath:path]) {
NSError *deleteErr = nil;
[[NSFileManager defaultManager] removeItemAtPath:path error:&deleteErr];
if (deleteErr) {
NSLog (@"Can't delete %@: %@", path, deleteErr);
}
}
}
// generic error handler from upcoming "Core Audio" book (thanks, Kevin!)
// if result is nonzero, prints error message and exits program.
static void CheckResult(OSStatus result, const char *operation)
{
if (result == noErr) return;
char errorString[20];
// see if it appears to be a 4-char-code
*(UInt32 *)(errorString + 1) = CFSwapInt32HostToBig(result);
if (isprint(errorString[1]) && isprint(errorString[2]) && isprint(errorString[3]) && isprint(errorString[4])) {
errorString[0] = errorString[5] = '\'';
errorString[6] = '\0';
} else
// no, format it as an integer
sprintf(errorString, "%d", (int)result);
fprintf(stderr, "Error: %s (%s)\n", operation, errorString);
exit(1);
}
#pragma mark core audio test
BOOL coreAudioCanOpenURL (NSURL* url){
OSStatus openErr = noErr;
AudioFileID audioFile = NULL;
openErr = AudioFileOpenURL((__bridge CFURLRef) url,
kAudioFileReadPermission ,
0,
&audioFile);
if (audioFile) {
AudioFileClose (audioFile);
}
return openErr ? NO : YES;
}
【讨论】：
我已经尝试并成功导出了 ipod 库歌曲。请在下面找到我的代码：
extension AudioPostViewController: MPMediaPickerControllerDelegate {
func mediaPicker(mediaPicker: MPMediaPickerController, didPickMediaItems mediaItemCollection: MPMediaItemCollection) {
dismissViewControllerAnimated(true, completion: {
print("You selected \(mediaItemCollection)")
let item: MPMediaItem = mediaItemCollection.items[0]
let pathURL: NSURL? = item.valueForProperty(MPMediaItemPropertyAssetURL) as? NSURL
if pathURL == nil {
Alert.showPopupWithMessage("Unable to read DRM protected file.")
return
}
let title = item.valueForProperty(MPMediaItemPropertyTitle) as? String ?? "Now Playing..."
print("\(pathURL), title : \(title) ")
// get file extension andmime type
let str = pathURL!.absoluteString
let str2 = str.stringByReplacingOccurrencesOfString("ipod-library://item/item", withString: "")
let arr = str2.componentsSeparatedByString("?")
var mimeType = arr[0]
mimeType = mimeType.stringByReplacingOccurrencesOfString(".", withString: "")
// Export the ipod library as .m4a file to local directory for remote upload
let exportSession = AVAssetExportSession(asset: AVAsset(URL: pathURL!), presetName: AVAssetExportPresetAppleM4A)
exportSession?.shouldOptimizeForNetworkUse = true
exportSession?.outputFileType = AVFileTypeAppleM4A
FilePath.removeAudioFile() // Remove file if it exists
let fileUrl = FilePath.testFilePathURL()
exportSession?.outputURL = fileUrl
exportSession?.exportAsynchronouslyWithCompletionHandler({ () -> Void in
if exportSession!.status == AVAssetExportSessionStatus.Completed {
dispatch_async(dispatch_get_main_queue(), {
// Prepare audio to play
self.audioTitle = title
self.audioPath = fileUrl
self.mimeType = "audio/m4a"
self.audioFileName = "audio.m4a"
UIView.animateWithDuration(0.45, animations: {
if Platform.DeviceType.iPhone4 {
self.libraryBottomSpacing.constant = 5
self.view.layoutIfNeeded()
} else {
self.libraryBottomSpacing.constant = 25
self.view.layoutIfNeeded()
}
}, completion: {
(v: Bool) in
self.loadJukeBox(self.audioPath!, title: title)
})
})
} else {
dispatch_async(dispatch_get_main_queue(), {
Alert.showPopupWithMessage("Unable to read file as its DRM protected.")
})
}
})
})
}
func mediaPickerDidCancel(mediaPicker: MPMediaPickerController) {
dismissViewControllerAnimated(true, completion: nil)
}
}
【讨论】：