长按录音笔记

    [recordingBtn setTitle:@"长按录WAV" forState:UIControlStateNormal];
    [recordingBtn setTitle:@"松开录制完成" forState:UIControlStateHighlighted];
    [recordingBtn addTarget:self action:@selector(buttonSayBegin) forControlEvents:UIControlEventTouchDown];
    [recordingBtn addTarget:self action:@selector(buttonSayEnd) forControlEvents:UIControlEventTouchUpInside];