抄了Cocoa的一个实例：
#import <Cocoa/Cocoa.h>
@interface ViewController : NSViewController
{
NSSpeechSynthesizer* _speechSynth;
}
- (IBAction)stopIt:(id)sender;
- (IBAction)sayIt:(id)sender;
@property (weak) IBOutlet NSTextField *textField;
@end
#import "ViewController.h"
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
}
- (void)setRepresentedObject:(id)representedObject {
[super setRepresentedObject:representedObject];
// Update the view, if already loaded.
}
- (id)init {
self = [super init];
if (self) {
// Logs can help the beginner understand what
// is happening and hunt down bugs.
NSLog(@"init");
// Create a new instance of NSSpeechSynthesizer
// with the default voice.
_speechSynth = [[NSSpeechSynthesizer alloc] initWithVoice:@"com.apple.speech.synthesis.voice.Alex"];
}
return self;
}
- (IBAction)stopIt:(id)sender {
NSLog(@"stopping");
[_speechSynth stopSpeaking];
}
- (IBAction)sayIt:(id)sender {
NSString *string = [_textField stringValue];
// Is the string zero-length?
if ([string length] == 0) {
NSLog(@"string from %@ is of zero-length", _textField);
return; }
// _speechSynth = [[NSSpeechSynthesizer alloc] initWithVoice:nil];
// [_speechSynth setVoice:@"com.apple.speech.synthesis.voice.Alex"];
[_speechSynth startSpeakingString:string];
while([NSSpeechSynthesizer isAnyApplicationSpeaking] == true) {}
NSLog(@"Have started to say: %@", string);
}
@end
如果代码如现在所描述，代码到[_speechSynth startSpeakingString:string];这一行是发不出声音出来的，而且我调试到_speechSynth此时是nil;
如果把
// _speechSynth = [[NSSpeechSynthesizer alloc] initWithVoice:nil];
// [_speechSynth setVoice:@"com.apple.speech.synthesis.voice.Alex"];
[_speechSynth startSpeakingString:string];
前两行的注释取消掉，程序就能正常发出声音，此时_speechSynth也不为nil。
请教一下为什么会这样，_speechSynth为什么没有持久化？谢谢！
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