我也面临着一个类似的问题，AVAudioRecorder即只有在中断后才录制。
所以我通过维护一系列录音并将它们保留在NSTemporaryDirectory最后合并它们来解决这个问题。
以下是关键步骤：
- 让你的班级听
AVAudioSessionInterruptionNotification。
- 在中断开始 (
AVAudioSessionInterruptionTypeBegan) 时，保存您的录音
- 在中断结束(
AVAudioSessionInterruptionTypeEnded) 时，为中断选项开始新的录制AVAudioSessionInterruptionOptionShouldResume
- 在点击“保存”按钮 时附加所有录音。
上述步骤的代码片段是：
// 1. Make this class listen to the AVAudioSessionInterruptionNotification in viewDidLoad
- (void)viewDidLoad
{
[super viewDidLoad];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(handleAudioSessionInterruption:)
name:AVAudioSessionInterruptionNotification
object:[AVAudioSession sharedInstance]];
// other coding stuff
}
// observe the interruption begin / end
- (void)handleAudioSessionInterruption:(NSNotification*)notification
{
AVAudioSessionInterruptionType interruptionType = [notification.userInfo[AVAudioSessionInterruptionTypeKey] unsignedIntegerValue];
AVAudioSessionInterruptionOptions interruptionOption = [notification.userInfo[AVAudioSessionInterruptionOptionKey] unsignedIntegerValue];
switch (interruptionType) {
// 2. save recording on interruption begin
case AVAudioSessionInterruptionTypeBegan:{
// stop recording
// Update the UI accordingly
break;
}
case AVAudioSessionInterruptionTypeEnded:{
if (interruptionOption == AVAudioSessionInterruptionOptionShouldResume) {
// create a new recording
// Update the UI accordingly
}
break;
}
default:
break;
}
}
// 4. append all recordings
- (void) audioRecorderDidFinishRecording:(AVAudioRecorder *)avrecorder successfully:(BOOL)flag
{
// append all recordings one after other
}
这是一个工作示例：
//
// XDRecordViewController.m
//
// Created by S1LENT WARRIOR
//
#import "XDRecordViewController.h"
@interface XDRecordViewController ()
{
AVAudioRecorder *recorder;
__weak IBOutlet UIButton* btnRecord;
__weak IBOutlet UIButton* btnSave;
__weak IBOutlet UIButton* btnDiscard;
__weak IBOutlet UILabel* lblTimer; // a UILabel to display the recording time
// some variables to display the timer on a lblTimer
NSTimer* timer;
NSTimeInterval intervalTimeElapsed;
NSDate* pauseStart;
NSDate* previousFireDate;
NSDate* recordingStartDate;
// interruption handling variables
BOOL isInterrupted;
NSInteger preInterruptionDuration;
NSMutableArray* recordings; // an array of recordings to be merged in the end
}
@end
@implementation XDRecordViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Make this class listen to the AVAudioSessionInterruptionNotification
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(handleAudioSessionInterruption:)
name:AVAudioSessionInterruptionNotification
object:[AVAudioSession sharedInstance]];
[self clearContentsOfDirectory:NSTemporaryDirectory()]; // clear contents of NSTemporaryDirectory()
recordings = [NSMutableArray new]; // initialize recordings
[self setupAudioSession]; // setup the audio session. you may customize it according to your requirements
}
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
[self initRecording]; // start recording as soon as the view appears
}
- (void)dealloc
{
[self clearContentsOfDirectory:NSTemporaryDirectory()]; // remove all files files from NSTemporaryDirectory
[[NSNotificationCenter defaultCenter] removeObserver:self]; // remove this class from NSNotificationCenter
}
#pragma mark - Event Listeners
// called when recording button is tapped
- (IBAction) btnRecordingTapped:(UIButton*)sender
{
sender.selected = !sender.selected; // toggle the button
if (sender.selected) { // resume recording
[recorder record];
[self resumeTimer];
} else { // pause recording
[recorder pause];
[self pauseTimer];
}
}
// called when save button is tapped
- (IBAction) btnSaveTapped:(UIButton*)sender
{
[self pauseTimer]; // pause the timer
// disable the UI while the recording is saving so that user may not press the save, record or discard button again
btnSave.enabled = NO;
btnRecord.enabled = NO;
btnDiscard.enabled = NO;
[recorder stop]; // stop the AVAudioRecorder so that the audioRecorderDidFinishRecording delegate function may get called
// Deactivate the AVAudioSession
NSError* error;
[[AVAudioSession sharedInstance] setActive:NO error:&error];
if (error) {
NSLog(@"%@", error);
}
}
// called when discard button is tapped
- (IBAction) btnDiscardTapped:(id)sender
{
[self stopTimer]; // stop the timer
recorder.delegate = Nil; // set delegate to Nil so that audioRecorderDidFinishRecording delegate function may not get called
[recorder stop]; // stop the recorder
// Deactivate the AVAudioSession
NSError* error;
[[AVAudioSession sharedInstance] setActive:NO error:&error];
if (error) {
NSLog(@"%@", error);
}
[self.navigationController popViewControllerAnimated:YES];
}
#pragma mark - Notification Listeners
// called when an AVAudioSessionInterruption occurs
- (void)handleAudioSessionInterruption:(NSNotification*)notification
{
AVAudioSessionInterruptionType interruptionType = [notification.userInfo[AVAudioSessionInterruptionTypeKey] unsignedIntegerValue];
AVAudioSessionInterruptionOptions interruptionOption = [notification.userInfo[AVAudioSessionInterruptionOptionKey] unsignedIntegerValue];
switch (interruptionType) {
case AVAudioSessionInterruptionTypeBegan:{
// • Recording has stopped, already inactive
// • Change state of UI, etc., to reflect non-recording state
preInterruptionDuration += recorder.currentTime; // time elapsed
if(btnRecord.selected) { // timer is already running
[self btnRecordingTapped:btnRecord]; // pause the recording and pause the timer
}
recorder.delegate = Nil; // Set delegate to nil so that audioRecorderDidFinishRecording may not get called
[recorder stop]; // stop recording
isInterrupted = YES;
break;
}
case AVAudioSessionInterruptionTypeEnded:{
// • Make session active
// • Update user interface
// • AVAudioSessionInterruptionOptionShouldResume option
if (interruptionOption == AVAudioSessionInterruptionOptionShouldResume) {
// Here you should create a new recording
[self initRecording]; // create a new recording
[self btnRecordingTapped:btnRecord];
}
break;
}
default:
break;
}
}
#pragma mark - AVAudioRecorderDelegate
- (void) audioRecorderDidFinishRecording:(AVAudioRecorder *)avrecorder successfully:(BOOL)flag
{
[self appendAudiosAtURLs:recordings completion:^(BOOL success, NSURL *outputUrl) {
// do whatever you want with the new audio file :)
}];
}
#pragma mark - Timer
- (void)timerFired:(NSTimer*)timer
{
intervalTimeElapsed++;
[self updateDisplay];
}
// function to time string
- (NSString*) timerStringSinceTimeInterval:(NSTimeInterval)timeInterval
{
NSDate *timerDate = [NSDate dateWithTimeIntervalSince1970:timeInterval];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"mm:ss"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
return [dateFormatter stringFromDate:timerDate];
}
// called when recording pauses
- (void) pauseTimer
{
pauseStart = [NSDate dateWithTimeIntervalSinceNow:0];
previousFireDate = [timer fireDate];
[timer setFireDate:[NSDate distantFuture]];
}
- (void) resumeTimer
{
if (!timer) {
timer = [NSTimer scheduledTimerWithTimeInterval:1.0
target:self
selector:@selector(timerFired:)
userInfo:Nil
repeats:YES];
return;
}
float pauseTime = - 1 * [pauseStart timeIntervalSinceNow];
[timer setFireDate:[previousFireDate initWithTimeInterval:pauseTime sinceDate:previousFireDate]];
}
- (void)stopTimer
{
[self updateDisplay];
[timer invalidate];
timer = nil;
}
- (void)updateDisplay
{
lblTimer.text = [self timerStringSinceTimeInterval:intervalTimeElapsed];
}
#pragma mark - Helper Functions
- (void) initRecording
{
// Set the audio file
NSString* name = [NSString stringWithFormat:@"recording_%@.m4a", @(recordings.count)]; // creating a unique name for each audio file
NSURL *outputFileURL = [NSURL fileURLWithPathComponents:@[NSTemporaryDirectory(), name]];
[recordings addObject:outputFileURL];
// Define the recorder settings
NSMutableDictionary *recordSetting = [[NSMutableDictionary alloc] init];
[recordSetting setValue:@(kAudioFormatMPEG4AAC) forKey:AVFormatIDKey];
[recordSetting setValue:@(44100.0) forKey:AVSampleRateKey];
[recordSetting setValue:@(1) forKey:AVNumberOfChannelsKey];
NSError* error;
// Initiate and prepare the recorder
recorder = [[AVAudioRecorder alloc] initWithURL:outputFileURL settings:recordSetting error:&error];
recorder.delegate = self;
recorder.meteringEnabled = YES;
[recorder prepareToRecord];
if (![AVAudioSession sharedInstance].inputAvailable) { // can not record audio if mic is unavailable
NSLog(@"Error: Audio input device not available!");
return;
}
intervalTimeElapsed = 0;
recordingStartDate = [NSDate date];
if (isInterrupted) {
intervalTimeElapsed = preInterruptionDuration;
isInterrupted = NO;
}
// Activate the AVAudioSession
[[AVAudioSession sharedInstance] setActive:YES error:&error];
if (error) {
NSLog(@"%@", error);
}
recordingStartDate = [NSDate date]; // Set the recording start date
[self btnRecordingTapped:btnRecord];
}
- (void)setupAudioSession
{
static BOOL audioSessionSetup = NO;
if (audioSessionSetup) {
return;
}
AVAudioSession* session = [AVAudioSession sharedInstance];
[session setCategory:AVAudioSessionCategoryPlayAndRecord
withOptions:AVAudioSessionCategoryOptionDefaultToSpeaker
error:Nil];
[session setMode:AVAudioSessionModeSpokenAudio error:nil];
audioSessionSetup = YES;
}
// gets an array of audios and append them to one another
// the basic logic was derived from here: http://stackoverflow.com/a/16040992/634958
// i modified this logic to append multiple files
- (void) appendAudiosAtURLs:(NSMutableArray*)urls completion:(void(^)(BOOL success, NSURL* outputUrl))handler
{
// Create a new audio track we can append to
AVMutableComposition* composition = [AVMutableComposition composition];
AVMutableCompositionTrack* appendedAudioTrack =
[composition addMutableTrackWithMediaType:AVMediaTypeAudio
preferredTrackID:kCMPersistentTrackID_Invalid];
// Grab the first audio track that need to be appended
AVURLAsset* originalAsset = [[AVURLAsset alloc]
initWithURL:urls.firstObject options:nil];
[urls removeObjectAtIndex:0];
NSError* error = nil;
// Grab the first audio track and insert it into our appendedAudioTrack
AVAssetTrack *originalTrack = [[originalAsset tracksWithMediaType:AVMediaTypeAudio] firstObject];
CMTimeRange timeRange = CMTimeRangeMake(kCMTimeZero, originalAsset.duration);
[appendedAudioTrack insertTimeRange:timeRange
ofTrack:originalTrack
atTime:kCMTimeZero
error:&error];
CMTime duration = originalAsset.duration;
if (error) {
if (handler) {
dispatch_async(dispatch_get_main_queue(), ^{
handler(NO, Nil);
});
}
}
for (NSURL* audioUrl in urls) {
AVURLAsset* newAsset = [[AVURLAsset alloc]
initWithURL:audioUrl options:nil];
// Grab the rest of the audio tracks and insert them at the end of each other
AVAssetTrack *newTrack = [[newAsset tracksWithMediaType:AVMediaTypeAudio] firstObject];
timeRange = CMTimeRangeMake(kCMTimeZero, newAsset.duration);
[appendedAudioTrack insertTimeRange:timeRange
ofTrack:newTrack
atTime:duration
error:&error];
duration = appendedAudioTrack.timeRange.duration;
if (error) {
if (handler) {
dispatch_async(dispatch_get_main_queue(), ^{
handler(NO, Nil);
});
}
}
}
// Create a new audio file using the appendedAudioTrack
AVAssetExportSession* exportSession = [AVAssetExportSession
exportSessionWithAsset:composition
presetName:AVAssetExportPresetAppleM4A];
if (!exportSession) {
if (handler) {
dispatch_async(dispatch_get_main_queue(), ^{
handler(NO, Nil);
});
}
}
NSArray* appendedAudioPath = @[NSTemporaryDirectory(), @"temp.m4a"]; // name of the final audio file
exportSession.outputURL = [NSURL fileURLWithPathComponents:appendedAudioPath];
exportSession.outputFileType = AVFileTypeAppleM4A;
[exportSession exportAsynchronouslyWithCompletionHandler:^{
BOOL success = NO;
// exported successfully?
switch (exportSession.status) {
case AVAssetExportSessionStatusFailed:
break;
case AVAssetExportSessionStatusCompleted: {
success = YES;
break;
}
case AVAssetExportSessionStatusWaiting:
break;
default:
break;
}
if (handler) {
dispatch_async(dispatch_get_main_queue(), ^{
handler(success, exportSession.outputURL);
});
}
}];
}
- (void) clearContentsOfDirectory:(NSString*)directory
{
NSFileManager *fm = [NSFileManager defaultManager];
NSError *error = nil;
for (NSString *file in [fm contentsOfDirectoryAtPath:directory error:&error]) {
[fm removeItemAtURL:[NSURL fileURLWithPathComponents:@[directory, file]] error:&error];
}
}
@end
我知道现在回答问题为时已晚，但希望这对其他人有帮助！