比较触摸坐标 [英] Comparing Touch Coordinates

问题描述

是否可以将用户在UIView上做出的触摸坐标与plist或txt格式的一个商店进行比较?参数看起来像这样；

Is it possible to compare touch coordinates made by the users on the UIView to the one store in a plist or txt format? The argument looks like this;

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

如果可能的话，我应该以哪种格式在列表中写入坐标，以及如何在程序中将其关联?

If possible in what format should i write the coordinates in the list and how to associate it inside the program?

在此先感谢您，如果您发现我的问题有点抱歉，请谅解.

thanks in advance and sorry if you find my question a bit noobie.

推荐答案

不确定是否有单线解决方案.

Not sure if there's a one-liner solution.

在UITouch实例上，locationInView:方法返回CGPoint结构(x和y坐标，均为float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.

On a UITouch instance, the locationInView: method returns a CGPoint struct (x and y coordinates, both of type float). So you can store the x and y coordinates in your plist, then compare them with your current touch's x and y coordinates.

另外，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有命中".

Also, when comparing the coordinates, you probably want to use the distance between the two points to determine when you have a "hit".

下面是用于加载和写入属性列表的示例代码，其中的值基于NSDictionary:

Below is sample code for loading and writing to a property list, where the values are based on a 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];
}

用于计算UITouches的两个位置之间的距离的方法:

The method to calculate the distance between the two locations of the UITouches:

-(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确定用户是否到达先前位置的代码:

And finally, the code that uses the values in the property list to determine if the user hit the previous location:

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"];

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