我正在开发一个语音备忘录应用程序，它记录用户的声音并播放它们。
录音部分效果很好。录制的文件已成功存储，当用户点击已保存的文件时，它才开始播放文件。
我UISlider用来表示播放进度。UISlider现在，我将的userInteractionEnabled属性禁用为NO. 所以，我不允许用户与UISliderbar 交互。
我需要的是，我想启用此属性YES，以便可以选择播放音频的所需位置。为此，我在滑块代码中添加了以下行。
[mySlider addTarget:self action:@selector(sliderChanged:) forControlEvents:UIControlEventValueChanged];
通过添加上面的行，我可以找到方法中的滑块位置sliderChanged:。但是，我不知道如何从所选位置启动播放器。每个文件都有不同的大小，因此它们的播放时间也不同。
有没有可用的示例代码？需要你的帮助。
谢谢
在 Swift 中分享一个解决方案。
我能够让我的项目使用基于发布的objective-c implementation zeeran的滑块，它甚至现在不断更新当前时间，而我以前没有这样做。我很高兴。
所以我想分享快速的实现，以防它帮助任何人。
import UIKit
import AVFoundation
import Foundation
class ActivityViewController: UIViewController, AVAudioPlayerDelegate {
/// The player & sound file object
var audioPlayer = AVAudioPlayer()
var activitySound = NSURL()
var updater : CADisplayLink! = nil // tracks the time into the track
var updater_running : Bool = false // did the updater start?
var playing : Bool = false //indicates if track was started playing
@IBOutlet var playButton: UIButton!
@IBOutlet var timeLabel: UILabel! // shows time and duration
@IBOutlet var audioSlider: UISlider! // slider object
@IBAction func pressedPlayButton(sender: AnyObject) {
if (playing == false) {
updater = CADisplayLink(target: self, selector: Selector("updateProgress"))
updater.frameInterval = 1
updater.addToRunLoop(NSRunLoop.currentRunLoop(), forMode: NSDefaultRunLoopMode)
updater_running = true
audioPlayer.play()
playButton.selected = true // pause image is assigned to "selected"
playing = true
updateProgress()
} else {
updateProgress() // update track time
audioPlayer.pause() // then pause
playButton.selected = false // show play image (unselected button)
playing = false // note track has stopped playing
}
}
// action for when the slider is moved: set as 'valuechanged' for UISlider object
@IBAction func sliderMoved(sender: UISlider) {
// if the track was playing store true, so we can restart playing after changing the track position
var wasPlaying : Bool = false
if playing == true {
audioPlayer.pause()
wasPlaying = true
}
audioPlayer.currentTime = NSTimeInterval(round(audioSlider.value))
updateProgress()
// starts playing track again it it had been playing
if (wasPlaying == true) {
audioPlayer.play()
wasPlaying == false
}
}
// Timer delegate method that updates current time display in minutes
func updateProgress() {
let total = Float(audioPlayer.duration/60)
let current_time = Float(audioPlayer.currentTime/60)
audioSlider.minimumValue = 0.0
audioSlider.maximumValue = Float(audioPlayer.duration)
audioSlider.setValue(Float(audioPlayer.currentTime), animated: true)
timeLabel.text = NSString(format: "%.2f/%.2f", current_time, total) as String
}
//- AVAudioPlayer delegate method - resets things when track finishe playing
func PlayerDidFinishPlaying(player: AVAudioPlayer!, successfully flag: Bool) {
if flag {
playButton.selected = false
playing = false
audioPlayer.currentTime = 0.0
updateProgress()
updater.invalidate()
}
}
override func viewDidLoad() {
super.viewDidLoad()
// configure AVAudioPlayer as audioPlayer object
let file = NSURL(fileURLWithPath: NSBundle.mainBundle().pathForResource("file1", ofType: "mp3")!)!
audioPlayer = audioPlayer(contentsOfURL: file, error: nil)
audioPlayer.delegate = self
audioSlider.continuous = false
}
// method makes sure updater gets stopped when leaving view controller, because otherwise it will run indefinitely in background
override func viewWillDisappear(animated: Bool) {
if playing == true {
audioPlayer.stop()
}
updater.invalidate()
updater_running = false
super.viewWillDisappear(animated)
}
}
在加载声音文件之前刷新滑块最小值和最大值
yourSlider.minValue = 0.0;
yourSlider.maxValue = player.duration;
在方法中sliderChanged:
player.currentTime = yourSlider.value;
我的工作是通过结合 rajagp 和 Igor Bidiniuc 的上述答案来工作，所以我要对它们都投赞成票。
#import <AVFoundation/AVFoundation.h>
@property (nonatomic, strong) IBOutlet UIButton *playButton;
@property (nonatomic, strong) IBOutlet UISlider *slider;
@property (nonatomic, strong) IBOutlet UILabel *timeLabel;
@property (nonatomic, strong) AVAudioPlayer *audioPlayer;
@property (nonatomic, strong) NSTimer *timer;
- (IBAction)playPause:(id)sender;
- (IBAction)sliderValueChanged:(id)sender;
这里是实现文件。
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
self.slider.continuous = YES;
NSError *error = nil;
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:&error];
if (error == nil) {
NSLog(@"audio session initialized successfully");
[self PlayAudio:@"fileName"];
} else {
NSLog(@"error initializing audio session: %@", [error description]);
}
}
- (void)PlayAudio:(NSString*)file {
NSError *error = nil;
NSString *soundPath =[[NSBundle mainBundle] pathForResource:file ofType:@"mp3"];
NSURL *fileURL = [NSURL fileURLWithPath:soundPath];
if ([self.audioPlayer isPlaying]) {
[self.audioPlayer pause];
[self.timer invalidate];
}
self.audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:fileURL error:&error];
self.audioPlayer.delegate = self;
if (error == nil) {
NSLog(@"audio player initialized successfully");
[self playPause:nil];
} else {
NSLog(@"error initializing audio player: %@", [error description]);
}
}
- (void)viewWillDisappear:(BOOL)animated {
if ([self.audioPlayer isPlaying]) {
[self.audioPlayer pause];
[self.timer invalidate];
}
[super viewWillDisappear:animated];
}
-(IBAction)playPause:(id)sender
{
if ([self.audioPlayer isPlaying]) {
[self.audioPlayer pause];
self.playButton.imageView.image = [UIImage imageNamed:@"play"];
[self.timer invalidate];
} else {
[self.audioPlayer play];
self.playButton.imageView.image = [UIImage imageNamed:@"pause"];
self.timer = [NSTimer scheduledTimerWithTimeInterval:1.0f target:self selector:@selector(updateProgress) userInfo:nil repeats:YES];
}
}
- (IBAction)sliderValueChanged:(id)sender {
[self.timer invalidate];
self.timer = nil;
float position = self.slider.value;
if (self.audioPlayer.isPlaying)
{
[self playPause:nil];
}
[self.audioPlayer setCurrentTime:position];
if (self.audioPlayer.isPlaying)
{
[self playPause:nil];
}
[self updateProgress];
}
#pragma mark - Timer delegate
-(void)updateProgress
{
NSInteger durationMinutes = [self.audioPlayer duration] / 60;
NSInteger durationSeconds = [self.audioPlayer duration] - durationMinutes * 60;
NSInteger currentTimeMinutes = [self.audioPlayer currentTime] / 60;
NSInteger currentTimeSeconds = [self.audioPlayer currentTime] - currentTimeMinutes * 60;
NSString *progressString = [NSString stringWithFormat:@"%d:%02d / %d:%02d", currentTimeMinutes, currentTimeSeconds, durationMinutes, durationSeconds];
self.timeLabel.text = progressString;
self.slider.minimumValue = 0.0;
self.slider.maximumValue = [self.audioPlayer duration];
[self.slider setValue:[self.audioPlayer currentTime] animated:YES];
}
#pragma mark - AVAudioPlayer delegate methods
-(void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag
{
if (flag) {
self.playButton.imageView.image = [UIImage imageNamed:@"play"];
[self.timer invalidate];
}
}
以下代码示例应该可以帮助您入门。有了这个，滑块可以用作进度指示器，用户可以滑动它以在指定位置开始播放。
/* SliderMoved 在滑块值更改时调用 - 无论是用户滑动它还是随着音频播放的进行而自动更新 */
-(void)sliderMoved:(id)sender
{
[self.playbackTimer invalidate];
self.playbackTimer = nil;
NSInteger position = (NSInteger)self.slider.value * 60; // Assume the slider scale is in minutes- so convert to sec
if (self.isPlaying)
{
[self.audioPlayer pause];
}
[self.audioPlayer setCurrentTime:position];
if (self.isPlaying)
{
[self startOrResumePlaying];
}
[self updateSlider];
}
/* updateSlider 是一个用于更新滑块值的辅助函数 */
-(void)updateSlider
{
float total= self.audioPlayer.duration;
float f = (self.audioPlayer.currentTime) ;
self.slider.value = f/60.0;
self.progressLabel.text = [NSString stringWithFormat:@"%.2f",self.slider.value];
}
/* startOrResumePlaying 开始音频播放并初始化一个计时器，该计时器每 3 秒自动增加进度指示器 */
-(void)startOrResumePlaying
{
[self.audioPlayer prepareToPlay];
[self.audioPlayer play];
self.isPlaying = YES;
self.playbackTimer=[NSTimer scheduledTimerWithTimeInterval:3.0
target:self
selector:@selector(handleTimer:)
userInfo:nil
repeats:YES];
[[NSRunLoop currentRunLoop] addTimer:self.playbackTimer forMode:NSDefaultRunLoopMode];
}
AVAudioPlayer 有一个你可以设置的 currentTime 属性。请参考 AVAudioPlayer 文档。