更新时间:2021-11-26 11:36:32
如果学过Java和C#的人,这里容易搞混,
Objective-C中的@interface关键字是申明类
@interface Circle : NSObject { @private ShapeColor fillColor; ShapeRect bounds; } - (void) setFillColor: (ShapeColor) fillColor; - (void) setBounds: (ShapeRect) bounds; - (void) draw; @end // Circle
如上,这样的申明类的方式确实让我们Java和C#程序员有点不太习惯,连缩进方式也是
还是来看一下完整代码吧
#import <Foundation/Foundation.h> // -------------------------------------------------- // constants for the different kinds of shapes and their colors typedef enum { kRedColor, kGreenColor, kBlueColor } ShapeColor; // -------------------------------------------------- // Shape bounding rectangle typedef struct { int x, y, width, height; } ShapeRect; // -------------------------------------------------- // convert from the ShapeColor enum value to a human-readable name NSString *colorName (ShapeColor color) { switch (color) { case kRedColor: return @"red"; break; case kGreenColor: return @"green"; break; case kBlueColor: return @"blue"; break; } return @"no clue"; } // colorName // -------------------------------------------------- // All about Circles @interface Circle : NSObject { ShapeColor fillColor; ShapeRect bounds; } - (void) setFillColor: (ShapeColor) fillColor; - (void) setBounds: (ShapeRect) bounds; - (void) draw; @end // Circle @implementation Circle - (void) setFillColor: (ShapeColor) c { fillColor = c; } // setFillColor - (void) setBounds: (ShapeRect) b { bounds = b; } // setBounds - (void) draw { NSLog (@"drawing a circle at (%d %d %d %d) in %@", bounds.x, bounds.y, bounds.width, bounds.height, colorName(fillColor)); } // draw @end // Circle // -------------------------------------------------- // All about Rectangles @interface Rectangle : NSObject { ShapeColor fillColor; ShapeRect bounds; } - (void) setFillColor: (ShapeColor) fillColor; - (void) setBounds: (ShapeRect) bounds; - (void) draw; @end // Rectangle @implementation Rectangle - (void) setFillColor: (ShapeColor) c { fillColor = c; } // setFillColor - (void) setBounds: (ShapeRect) b { bounds = b; } // setBounds - (void) draw { NSLog (@"drawing a rectangle at (%d %d %d %d) in %@", bounds.x, bounds.y, bounds.width, bounds.height, colorName(fillColor)); } // draw @end // Rectangle // -------------------------------------------------- // All about OblateSphereoids @interface OblateSphereoid : NSObject { ShapeColor fillColor; ShapeRect bounds; } - (void) setFillColor: (ShapeColor) fillColor; - (void) setBounds: (ShapeRect) bounds; - (void) draw; @end // OblateSphereoid @implementation OblateSphereoid - (void) setFillColor: (ShapeColor) c { fillColor = c; } // setFillColor - (void) setBounds: (ShapeRect) b { bounds = b; } // setBounds - (void) draw { NSLog (@"drawing an egg at (%d %d %d %d) in %@", bounds.x, bounds.y, bounds.width, bounds.height, colorName(fillColor)); } // draw @end // OblateSphereoid // -------------------------------------------------- // Draw the shapes void drawShapes (id shapes[], int count) { for (int i = 0; i < count; i++) { id shape = shapes[i]; [shape draw]; } } // drawShapes // -------------------------------------------------- // The main function. Make the shapes and draw them int main (int argc, const char * argv[]) { id shapes[3]; ShapeRect rect0 = { 0, 0, 10, 30 }; shapes[0] = [Circle new]; [shapes[0] setBounds: rect0]; [shapes[0] setFillColor: kRedColor]; ShapeRect rect1 = { 30, 40, 50, 60 }; shapes[1] = [Rectangle new]; [shapes[1] setBounds: rect1]; [shapes[1] setFillColor: kGreenColor]; ShapeRect rect2 = { 15, 19, 37, 29 }; shapes[2] = [OblateSphereoid new]; [shapes[2] setBounds: rect2]; [shapes[2] setFillColor: kBlueColor]; drawShapes (shapes, 3); return (0); } // main
运行结果:
drawing a circle at (0 0 10 30) in red
drawing a rectangle at (30 40 50 60) in green
drawing an egg at (15 19 37 29) in blue
drawing a triangle at (47 32 80 50) in red