Question

我需要一些编程逻辑方面的帮助......我需要循环使用此方法在我的标签中显示数学问题，然后再sleep(5)然后再循环。我试过的任何东西都冻结了程序。请帮忙！我一直在尝试我所知道的所有东西！

编辑：我编写了代码到这个，3秒后它消失了显示问题的标签但随后它崩溃了，调试器显示2010-08-06 10:43:27.776 Reactor [13444:207] modifying layer that is being finalized - 0x5c13500

//quickfire problems
-(void)simpleMath{ //"Tap when the answer is X"
    isTimeToTap = NO;
    int problemSelector = arc4random() % 4;

    NSArray *mathProblems = [[NSArray alloc] initWithObjects:@"6 - 1",@"2 + 3",@"3 x 2",@"3 x 1",@"2 x 4",nil]; //correct index 2
    NSArray *mathAnswers = [[NSArray alloc] initWithObjects:@"5",@"5",@"6",@"3",@"8",nil]; //correct index 2

    if ([mathAnswers objectAtIndex:problemSelector] == @"6") {
        isTimeToTap = YES;
    }

    if (ranBefore == NO) { //create labels

        //tell when to tap
        tapTellerTop.text = @"Tap when the answer is 6!";
        tapTellerBottom.text = @"Tap when the answer is 6!";

        //make bottom label
        mathDisplayBottom = [[UILabel alloc] initWithFrame:CGRectMake(15, 250, 242, 92)];
        mathDisplayBottom.font = [UIFont fontWithName:@"Helvetica" size: 96.0];
        mathDisplayBottom.textColor = [UIColor whiteColor];
        mathDisplayBottom.backgroundColor = [UIColor clearColor]; 
        [self.view addSubview: mathDisplayBottom];

        //make top label
        mathDisplayTop = [[UILabel alloc] initWithFrame:CGRectMake(55, 120, 242, 92)];
        mathDisplayTop.font = [UIFont fontWithName:@"Helvetica" size: 96.0];
        mathDisplayTop.textColor = [UIColor whiteColor];
        mathDisplayTop.backgroundColor = [UIColor clearColor];
        [self.view addSubview: mathDisplayTop];
        //rotate top label
        mathDisplayTop.transform = CGAffineTransformMakeRotation(180.0 /180.0 * M_PI);
    }
    //if ran before just update the text 
    mathDisplayBottom.text = [mathProblems objectAtIndex:problemSelector];
    mathDisplayTop.text = [mathProblems objectAtIndex:problemSelector];

    ranBefore = YES; //if its here. its been ran.

    //run timer wait for (3) then loop again until userTaps = YES
    [self performSelector:@selector(simpleMath) withObject:nil afterDelay:3.0f];

    [mathProblems release];
    [mathAnswers release];
    [mathDisplayBottom release];
    [mathDisplayTop release];
}

Answer 1

你永远不应该sleep()。要重复调用函数，请调用：

[NSTimer scheduledTimerWithTimeInterval:5 target:self selector:@selector(doStuff:)
                                                userInfo:nil repeats:YES];

然后定义函数：

-(void)doStuff:(NSTimer*)timer
{
    // stuff
    if ( iAmDone ) [timer invalidate];
}

或如果你想发起另一个电话，5秒后你可以打电话

if ( !iAmDone ) [self performSelector:@selector(simpleMath) afterDelay:5];

在simpleMath的末尾。

Answer 2

睡眠将阻止您的应用程序运行或响应。以下是您可以使用的视图控制器的快速部分示例。这假设您连接了水龙头按钮并仅使用其中一个标签等，但您可以使用它。此外，这不会处理内存问题或任何内容，因此您需要添加支持。

但是，一旦创建了此视图控制器并安装了视图，数学问题将每5秒更新一次。如果用户按下按钮并且答案有效，我们会记录成功消息，否则我们会记录失败消息。

@interface myMathController : UIViewController {
    NSArray* mathProblems;
    NSIndexSet* validIndexes;
    NSUInteger currentIndex;

    NSTimer* timer;
}

@property(nonatomic,assign) IBOutlet UILabel* mathDisplayLabel;

- (void)updateProblem:(NSTimer*)timer;
- (IBAction)userTap;

@end

@implementation myMathController

- (void)viewDidLoad
{
    [super viewDidLoad];
    mathProblems = [[NSArray alloc] initWithObjects:@"6 - 1",@"2 + 3",@"3 x 2",@"3 x 1",@"2 x 4",nil];
    // Add all valid answers
    NSMutableIndexSet* tempIndexes = [[NSMutableIndexSet alloc] init];
    [tempIndexes addIndex:2];
    validIndexs = [tempIndexes copy];
    [tempIndexes release];

    timer = [[NSTimer alloc] initWithFireDate:[NSDate date] interval:5.0 target:self selector:@selector(updateProblem:) userInfo:nil repeats:YES];
    [[NSRunLoop currentRunLoop] addTimer:timer forMode:NSRunLoopCommonModes];
}

- (void)updateProblem:(NSTimer*)timer
{
    currentIndex = arc4random() % [mathProblems count];
    [mathDisplayLabel setText:[mathProblems objectAtIndex:currentIndex]];
}

- (void)userTap
{
    if( [validIndexes containsIndex:currentIndex] ) {
        NSLog(@"This user is SMART!");
    } else {
        NSLog(@"This user needs more work!");
    }
}

- (void)dealloc
{
    [timer invalidate];
    [timer release];
    [mathProblems release];
    [validIndexes release];
    [super dealloc];
}

@end

Cocoa Touch - 循环帮助

2 个答案: