Question

我正在创建一个将文本转换为摩尔斯电码的应用，然后使用iPhone的手电筒将其闪现。我使用字符串替换，将NSString的内容转换为摩尔斯电码。

// some of the code :
    str = [str stringByReplacingOccurrencesOfString:@"5" withString:n5];
    str = [str stringByReplacingOccurrencesOfString:@"6" withString:n6];
    str = [str stringByReplacingOccurrencesOfString:@"7" withString:n7];
    str = [str stringByReplacingOccurrencesOfString:@"8" withString:n8];
    str = [str stringByReplacingOccurrencesOfString:@"9" withString:n9];
    str = [str stringByReplacingOccurrencesOfString:@"0" withString:n0];

    NSString *morseCode = [[NSString alloc] initWithFormat:str];        
    self.label.text = morseCode;

我找到了一个脚本，可以打开和关闭iPhone的手电筒，使用NSTimer可调节间隔。但我无法弄清楚如何添加两个不同的间隔，一个用于点，一个用于莫尔斯破折号。

- (void)viewDidLoad
{
[super viewDidLoad];

int spaceTime;
spaceTime = 1;

int dashTime;
dashTime = 2;

int dotTime;
dotTime = 0.8;

strobeIsOn = NO;
strobeActivated = NO;
strobeFlashOn = NO;

flashController = [[FlashController alloc] init];


self.strobeTimer =          [
                             NSTimer 
                             scheduledTimerWithTimeInterval:spaceTime
                             target:self 
                             selector:@selector(strobeTimerCallback:) 
                             userInfo:nil 
                             repeats:YES
                             ]; 

self.strobeFlashTimer =     [
                             NSTimer scheduledTimerWithTimeInterval:dotTime 
                             target:self 
                             selector:@selector(strobeFlashTimerCallback:) 
                             userInfo:nil 
                             repeats:YES
                             ];
    }



- (void)strobeTimerCallback:(id)sender {
if (strobeActivated) {
    strobeIsOn = !strobeIsOn;

    // ensure that it returns a callback. If no, returns only one flash
    strobeFlashOn = YES;
} else {
    strobeFlashOn = NO;
}
}

- (void)strobeFlashTimerCallback:(id)sender {
if (strobeFlashOn) {
    strobeFlashOn = !strobeFlashOn;
    [self startStopStrobe:strobeIsOn];

} else {
    [self startStopStrobe:NO];
}
}

我应该使用两个定时器，还是可以使用不同的定时器？我应该将字符串的内容放在一个数组中吗？我是Obj-C的新手..

Answer 1

您可以尝试在背景树上按顺序运行代码，并根据需要长时间休眠。编写和维护代码要比使用一堆定时器容易得多。

// execute in background
[self performSelectorInBackground:@selector(doTheMagic) withObject:nil];

- (void)doTheMagic {
    NSLog(@"Turn ON");
    [NSThread sleepForTimeInterval:1];
    NSLog(@"Turn OFF");
    [NSThread sleepForTimeInterval:0.1f];
    NSLog(@"Turn ON");
    [NSThread sleepForTimeInterval:1.0f];
    // ...
}

Answer 2

我会尝试制作一个递归函数：

parseAndFlash

{
    NSString *codeString = @"-.-. --- -.. .";
    int currentLetterIndex = 0;
    //codeString and currentLetterIndex should be declared outside this function as members or something    

    double t_space = 2, t_point = 0.5, t_line = 1, t_separator = 0.1;
    double symbolDuration = 0;
    if(currentLetterIndex >= [codeString length])
        return;

    char currentLetter = [codeString characterAtIndex:currentLetterIndex];
    switch (currentLetter) {
        case '-':
            symbolDuration = t_line;
            [self flashOnFor:t_line];
            break;
        case '.':
            symbolDuration = t_point;
            [self flashOnFor:t_point];
            break;
        case ' ':
            symbolDuration = t_space;
            [self flashOff];
            break;
        default:
            break;
    }

    currentLetterIndex ++;
    symbolDuration += t_separator;
    [self performSelector:@selector(parseAndFlash) withObject:nil afterDelay:symbolDuration];

}

使用NSTimer两个间隔

2 个答案: