objective-c - iOS 录制音频并存储在播放列表中

Question

我正在寻找通过录制按钮从 iPhone 麦克风录制音频。我已经下载并掌握了 Apple 提供的示例项目（SpeakHere）。

但是，下一步，我想以“播放列表”样式保存用户录制的内容（不使用 iTunes 播放列表，而是使用本地播放列表）。

是否可以使用 Objective-C（与当前提供的 C 实现相反）来执行此操作 - 理想情况下，CoreData 将用于存储音频。

谢谢

Answer 1

Here's how I did it:

1) Find the temp file that the SpeakHere code creates -- look for the .caf extension in the SpeakHereController class. Then move that temp file to your application directory with something like this:

NSString *myFileName = @"MyName"; // this would probably come from a user text field
NSString *tempName = @"recordedFile.caf";
NSString *saveName = [NSString stringWithFormat:@"Documents/%@.caf", myFileName];
NSString *tempPath = [NSTemporaryDirectory() stringByAppendingPathComponent:tempName];
NSString *savePath = [NSHomeDirectory() stringByAppendingPathComponent:saveName];

2) Save some metadata about the file, at least its name. I'm putting that into NSUserDefaults like this:

NSDictionary *recordingMetadata = [NSDictionary dictionaryWithObjectsAndKeys:
                         myFileName, @"name",
                         [NSDate date], @"date",
                         nil];
[self.savedRecordings addObject:recordingMetadata]; // savedRecordings is an array I created earlier by loading the NSUserDefaults
[[NSUserDefaults standardUserDefaults] setObject:self.savedRecordings forKey:@"recordings"]; // now I'm updating the NSUserDefaults

3) Now you can display a list of saved recordings by iterating through self.savedRecordings.

4) When the user selects a recording, you can easily initialize an AVAudioPlayer with the selected file name and play it back.

5) To let users delete recordings, you can do something like this:

NSString *myFileName = @"MyName";

// delete the audio file from the application directory
NSString *fileName = [NSString stringWithFormat:@"Documents/%@.caf", myFileName];
NSString *filePath = [NSHomeDirectory() stringByAppendingPathComponent:fileName];
[[NSFileManager defaultManager] removeItemAtPath:filePath error:NULL];

// delete the metadata from the user preferences
for (int i=0; i<[self.savedRecordings count]; i++) {
    NSDictionary *thisRecording = [self.savedRecordings objectAtIndex:i];
    if ([myFileName isEqualToString:[thisRecording objectForKey:@"name"]]) {
        [self.savedRecordings removeObjectAtIndex:i];
        break;
    }
}
[[NSUserDefaults standardUserDefaults] setObject:self.savedRecordings forKey:@"recordings"];

Note that if you save the audio files into the Documents folder and enable "Application supports iTunes file sharing" in your info.plist, then users can copy their recordings out of the app and save them onto their computers ... a nice feature if you want to offer it.