2

是否可以将用户在 UIView 上制作的触摸坐标与 plist 或 txt 格式的一个商店进行比较?论点看起来像这样;

  if (user touch coordinate == touch coordinate stored in plist or text)
  then
    (do something)
  else
    (do something)

如果可能的话,我应该以什么格式在列表中写入坐标以及如何在程序中关联它?

提前谢谢,如果你觉得我的问题有点菜,我很抱歉。

4

2 回答 2

5

不确定是否有单线解决方案。

在 UITouch 实例上,该locationInView:方法返回一个 CGPoint 结构(x 和 y 坐标,均为浮点类型)。因此,您可以将 x 和 y 坐标存储在 plist 中,然后将它们与当前触摸的 x 和 y 坐标进行比较。

编辑:此外,在比较坐标时,您可能希望使用两点之间的距离来确定何时“命中”。

编辑:下面是加载和写入属性列表的示例代码,其中值基于 NSDictionary:

- (NSMutableDictionary *)loadDictionaryFromPList: (NSString *)plistName
{
    NSString *plistPath = [[NSBundle mainBundle] pathForResource:plistName ofType:@"plist"];
    NSDictionary *immutableDictionary = [NSDictionary dictionaryWithContentsOfFile: plistPath];
    NSMutableDictionary *mutableDictionary = [NSMutableDictionary dictionaryWithDictionary: immutableDictionary];
    return mutableDictionary;
}


- (void)saveDictionary: (NSDictionary *)mySettings toPList: (NSString *)plistName
{
    NSString *plistPath = [[NSBundle mainBundle] pathForResource:plistName ofType:@"plist"];
    [mySettings writeToFile: plistPath atomically: YES];
}

计算UITouches的两个位置之间距离的方法:

-(CGFloat) distanceBetween: (CGPoint) point1 and: (CGPoint)point2
{
    CGFloat dx = point2.x - point1.x;
    CGFloat dy = point2.y - point1.y;
    return sqrt(dx*dx + dy*dy );
}

最后,使用属性列表中的值来确定用户是否点击了上一个位置的代码:

CGPoint currentTouchLocation = [currentTouch locationInView:self];

// Lookup last Touch location from plist, and handle case when current Touch matches it:
NSMutableDictionary *mySettings = [self loadDictionaryFromPList: @"MySettings"];
NSNumber *lastXCoordinate = [mySettings objectForKey:@"lastXCoordinate"];
NSNumber *lastYCoordinate = [mySettings objectForKey:@"lastYCoordinate"];
if (lastXCoordinate && lastYCoordinate)
{
    CGPoint lastTouchLocation = CGPointMake([lastXCoordinate floatValue], [lastYCoordinate floatValue]);
    CGFloat distanceBetweenTouches = [self distanceBetween: currentTouchLocation and: lastTouchLocation];
    if (distanceBetweenTouches < 25) // 25 is just an example
    {
        // Handle case where current touch is close enough to "hit" previous one
        NSLog(@"You got a hit!");
    }
}

// Save current touch location to property list:
[mySettings setValue: [NSNumber numberWithFloat: currentTouchLocation.x] forKey: @"lastXCoordinate"];
[mySettings setValue: [NSNumber numberWithFloat: currentTouchLocation.y] forKey: @"lastYCoordinate"];
[self saveDictionary:mySettings toPList: @"MySettings"];
于 2009-10-15T03:25:30.707 回答
3

您可能正在寻找的功能是NSStringFromCGPoint()CGPointFromString()

但几乎可以肯定,两个触摸坐标永远不会完全相同。您几乎不应该与 进行比较CGFloats==更不用说从诸如手指触摸之类的模拟输入中获得的那些了。您需要比较它们是否“足够接近”。有关如何测量两点之间距离的一个很好的示例,请参阅此博客。您希望该结果小于适合您目的的某个值(epsilon 或“小数”)。

于 2009-10-15T03:29:07.003 回答