Dark Horse Programmer -- OC struct in Foundation, foundationoc

Dark Horse Programmer -- OC struct in Foundation, foundationoc

 

OC struct

Nsange

NSPoint \ CGPoint

NSSize \ CGSize

NSRect \ CGRect

1. nsange: The range (Position, length) of Characters in the string)

Use typedef to define the nsange struct type:

Typedef struct _ nsange {

NSUInteger location;

NSUInteger length;

} Nsange;

Example:

NSString * str = @ "I love you ";

Nsange range1 = NSMakeRange (2, 4); // then, r indicates the love range.

Nsange range2 = [str rangeOfString: @ "love"]; // defines the range variable of the nsange struct type and stores the position and length of the string @ "love" in range2.

NSLog (@ "loc = % ld length = % ld", range2.location, range2.length); // print the location and length of love, and the result is loc = 2 length = 4.

If the range of a string cannot be found, length = 0, location = NSNotFound =-1.

2. NSPoint \ CGPoint:Determine the coordinates of a point in the plane

Typedef struct CGPoint {

CGFloat x;

CGFloat y;

} CGPoint;

Typedef CGPoint NSPoint;

Example:

CGPoint p1 = NSMakePoint (10, 10); // the x and y values of Point p1 are both 10.

NSPoint p2 = CGPointMake (5, 6); // This method is commonly used; point p2.x = 5, p2.y = 6.

 

The struct can be converted into strings to facilitate viewing the attributes of the struct.

NSString * str = NSStringFromPoint (p1); // convert Point p1 into a string and save it in str

NSLog (@ "% @", str); // enter the string {10, 10}

In the following two cases, you must run the program in the CoreGraphics framework.

1. Compare whether the two points are the same

BOOL a = CGPointEqualToPoint (CGPointMake (10, 10), CGPointMake (10, 10 ));

2. The following indicates the coordinate origin.

CGPointZero is equivalent to CGPointMake (0, 0)

3. NSSize \ CGSizeDescribes the size (width and height) of a UI element)

Struct CGSize {

CGFloat width;

CGFloat height;

};

Typedef struct CGSize;

Typedef CGSize NSSize;

Example:

NSSize s1 = NSMakeSize (15, 20 );

CGSize s2 = NSMakeSize (45, 23 );

NSSize s3 = CGSizeMake (20, 20 );

 

NSString * str1 = NSStringFromSize (s1 );

NSLog (@ "% @", str1 );

 

The CGSizeEqualToSize function to be called must also be run in CoreGraphics framework.

NSSize s1 = NSMakeSize (15, 20 );

CGSize s2 = NSMakeSize (45, 23 );

BOOL B = CGSizeEqualToSize (s1, s2 );

// Or write the line code BOOL B = CGSizeEqualToSize (CGSizeMake (), CGSizeMake ));

NSLog (@ "% d", B );

4. NSRect \ CGRect:Determine a rectangle

Struct CGRect {

CGPoint origin;

CGSize size;

};

Typedef struct CGRect;

Typedef CGRect NSRect;

Example: CGRect defines variables and initialization methods as follows.

CGRect r = CGRectMake (2, 2, 50, 12 );

CGRect r1 = CGRectMake (3, 2, 25, 12 );

CGRect r2 = {p1, s1 };

CGRect r3 = }};

CGRect r3 = {CGPointZero, CGSizeMake (50,12 )};

You can also convert this struct into a string.

NSString * str2 = NSStringFromRect (r );

NSLog (@ "% @", str2 );

Use the following function to compare whether two rectangles are equal

CGRectEqualToRect (r, r1 );

You can use the following function to determine whether a vertex is in a rectangle.

BOOL b1 = CGRectContainsCGPoint (CGRectMake (,), CGPointMake ));