陣列中的objective-c索引

Question

我需要你的幫助。問題：有一個數組，其中的對象4，當我按下播放聲音時，有一個按鈕，並改變（+1）數組索引=>當用戶第二次點擊時，聲音應該與索引「2」等。問題是索引不變，播放索引爲「1」的文件。

* .H：

@interface AZViewController : UIViewController 

{ 

    NSInteger _acatindex; 
} 

@property (weak, nonatomic) NSMutableArray *acat; 

- (IBAction)catbutt:(id)sender; 

* .M

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 

    //array 

    NSMutableArray *acat = [NSMutableArray arrayWithObjects:@"cat1", @"cat2", @"cat3", @"cat4", nil]; 

    NSURL *url = [[NSBundle mainBundle] URLForResource:[acat objectAtIndex:_acatindex] withExtension:@"wav"]; 
    NSAssert(url, @"URL is valid."); 
    NSError* error = nil; 
    self.catplayer = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&error]; 
    if(!self.catplayer) 
    { 
     NSLog(@"Error creating player: %@", error); 
    } 

} 
    //button action 
- (IBAction)catbutt:(id)sender 
{  
    _acatindex++; 
    if (_acatindex == _acat.count) 
    { 
     _acatindex = 0; 
    } 

    AZTrace(); 
    [self.catplayer stop]; 
    [self stopTimer]; 
    self.catplayer.currentTime = 0; 
    [self.catplayer prepareToPlay]; 

    AZTrace(); 
    [self.catplayer play]; 
    self.timer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(timerFired:) userInfo:nil repeats:YES]; 
} 

Answer 1

刪除這些行：

[acat addObject:@"cat1"]; 
    [acat addObject:@"cat2"]; 
    [acat addObject:@"cat3"]; 
    [acat addObject:@"cat4"]; 

聲明您的陣列和NSURL不viewDidLoad中，這樣做是不是您的.h：

@interface AZViewController : UIViewController 

{ 

    NSInteger _acatindex; 
    NSMutableArray *acat; 
    NSURL *url; 
} 

@property (weak, nonatomic) NSMutableArray *acat; 

- (IBAction)catbutt:(id)sender; 

現在從viewDidLoad()切下面的代碼：

url = [[NSBundle mainBundle] URLForResource:[acat objectAtIndex:_acatindex] withExtension:@"wav"]; 
    NSAssert(url, @"URL is valid."); 
    NSError* error = nil; 

self.catplayer = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&error]; 
    if(!self.catplayer) 
    { 
     NSLog(@"Error creating player: %@", error); 
    } 

並將其粘貼在- (IBAction)catbutt:(id)sender以上_acatindex++;

希望這會有所幫助。

Answer 2

你只加載URL在-viewDidLoad:方法。您需要通過-catbutt:方法告訴音頻播放器播放陣列中的下一個聲音。您正在停止播放器，但在重新啓動之前您並未更改播放的文件。