Question

我正在创建一个程序，每次按下按钮时都会将当前日期/时间添加到NSMutableArray。然后我试图将时间的双重值转换为另一个NSMutableArray。最后，我想使用这些双精度值来确定它们之间的平均时间。以下是我到目前为止的情况：

按钮的IBAction代码：

- (IBAction)tapButton:(id)sender {

    _currentTapTime = [NSDate date];
    [_tapTimeData addObject:_currentTapTime];

    _tapCountInt++;
    _tapCount.text = [NSString stringWithFormat:@"%ld", (long)_tapCountInt];

}

我的代码试图将时间转换为另一个数组作为双值：

for (int i = 0; i < [_tapTimeData count]; i++) {
    if (i == 0) {
        NSTimeInterval interval = [[_tapTimeData objectAtIndex:i] timeIntervalSinceDate:[_tapTimeData objectAtIndex:i]];
        [_intervalNumber initWithDouble:interval];
        [_tapTimeDataAsDouble addObject:_intervalNumber];
     } else {
         NSTimeInterval interval = [[_tapTimeData objectAtIndex:i] timeIntervalSinceDate:[_tapTimeData objectAtIndex:i-1]];
         [_intervalNumber initWithDouble:interval];
         [_tapTimeDataAsDouble addObject:_intervalNumber];
      }
}

我正在获取空数据，无法从数组中获取double值。

基本上，我希望程序执行以下操作：

用户点按按钮。
程序会记录该水龙头的当前时间。
当用户停止点击时，表示每次点击之间差异的双倍值会以新数组结束。
稍后我将计算每次点击之间的平均时间（以毫秒为单位），并进行其他一些计算，例如水龙头之间时间的方差和标准差。

谢谢！

Answer 1

这样：

[_intervalNumber initWithDouble:interval];
[_tapTimeDataAsDouble addObject:_intervalNumber];

应该是这样的：

_intervalNumber = [NSNumber numberWithDouble:interval];
[_tapTimeDataAsDouble addObject:_intervalNumber];

<强>代码：

@interface ViewController () {
    NSDate *currentTapTime;
    NSMutableArray *tapTimeData;
    int tapCountInt;
    IBOutlet UILabel *tapCount;
    NSNumber *intervalNumber;
    NSMutableArray *tapTimeDataAsDouble;
}

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    tapCountInt = 0;

    tapTimeData = [[NSMutableArray alloc] init];
    tapTimeDataAsDouble = [[NSMutableArray alloc] init];

}

- (IBAction)tapButton:(id)sender {

    currentTapTime = [NSDate date];
    [tapTimeData addObject:currentTapTime];


    NSLog(@"%@", tapTimeData);

    tapCountInt++;
    tapCount.text = [NSString stringWithFormat:@"%ld", (long)tapCountInt];
}


- (IBAction)tapAverage:(id)sender {
    for (int i = 0; i < [tapTimeData count]; i++) {
        NSLog(@"################%d", i);

        if (i == 0) {
            NSTimeInterval interval = [[tapTimeData objectAtIndex:i] timeIntervalSinceDate:[tapTimeData objectAtIndex:i]];
            intervalNumber = [NSNumber numberWithDouble:interval];
            [tapTimeDataAsDouble addObject:intervalNumber];
        } else {
            NSTimeInterval interval = [[tapTimeData objectAtIndex:i] timeIntervalSinceDate:[tapTimeData objectAtIndex:i-1]];
            intervalNumber = [NSNumber numberWithDouble:interval];
            [tapTimeDataAsDouble addObject:intervalNumber];
        }
    }
    NSLog(@"%@", tapTimeDataAsDouble);
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

Answer 2

您是否启动了数组_tapTimeDataAsDouble和_tapTimeData
创建了与代码类似的功能。

Answer 3

你真的需要第一步值，它总是为0吗？

NSTimeInterval interval = [[_tapTimeData objectAtIndex：i] timeIntervalSinceDate：[_ tapTimeData objectAtIndex：i]];

这应该做你需要的。结果数组将包含n-1个对象。

for (int i = 1; i < [_tapTimeData count]; i++) {
    NSTimeInterval interval = [_tapTimeData[i] timeIntervalSinceDate:_tapTimeData[i-1]];
    [_tapTimeDataAsDouble addObject:@(intervalNumber)];
}

试图从NSMutableArray中获取完整的NSDate对象的double值

3 个答案: