IOS application development-small drawing board demo

There are many other functions that can be added. Remember to add them here.

Code Section

Touchview. h

#import <UIKit/UIKit.h>@interface TouchView : UIView{    NSMutableArray *points;    NSArray *points_all;    CGContextRef context;    UIColor *paint_clr;}@property (strong,nonatomic) NSMutableArray *points;@property (strong,nonatomic) NSArray *points_all;@property (strong,nonatomic) UIColor *paint_clr;@end

Touchview. m

# Import "touchview. H "@ implementation touchview @ synthesize points, points_all, paint_clr;-(ID) initwithframe :( cgrect) frame {self = [Super initwithframe: frame]; If (Self) {// initialization code paint_clr = [uicolor greencolor];} return self;} // only override drawrect: If you perform custom drawing. // an empty implementation adversely affects performance during animation. -(void) drawrect :( cgrect) Re CT {// drawing code if ((! Self. points) | (self. points. count <2) {return;} context = uigraphicsgetcurrentcontext (); // set the paint brush thickness cgcontextsetlinewidth (context, 5.0f ); // set the paint brush color // [[uicolor bluecolor] set]; // [paint_clr set]; // cgcontextsetstrokecolorwithcolor (context, [uicolor bluecolor] cgcolor]); cgcontextsetstrokecolorwithcolor (context, [paint_clr cgcolor]); // draw the previous trajectory for (Int J = 0; j <[self. points_all count]; j ++) {nsmutablearray * points_tmp = [points_all objectatindex: J]; for (INT I = 0; I <[points_tmp count]-1; I ++) {cgpoint point1 = [[points_tmp objectatindex: I] cgpointvalue]; cgpoint point2 = [[points_tmp objectatindex :( I + 1)] cgpointvalue]; cgcontextmovetopoint (context, point1.x, point1.y ); cgcontextaddlinetopoint (context, point2.x, point2.y); cgcontextstrokepath (context) ;}// draw this for (INT I = 0; I <[self. points count]-1; I ++) {cgpoint point1 = [[self. points objectatindex: I] cgpointvalue]; cgpoint point2 = [[self. points objectatindex :( I + 1)] cgpointvalue]; cgcontextmovetopoint (context, point1.x, point1.y); cgcontextaddlinetopoint (context, point2.x, point2.y); cgcontextstrokepath (context );}} // multipoint touch-(bool) ismultipletouchenabled {return no;} // create an array and record the initial ponit-(void) touchesbegan :( nsset *) touches withevent :( uievent *) event {self. points = [nsmutablearray array]; cgpoint Pt = [[touches anyobject] locationinview: Self]; [self. points addobject: [nsvalue valuewithcgpoint: pt];} // record these points during movement // call setneedsdisplay, which triggers call of the drawrect method-(void) touchesmoved :( nsset *) touches withevent :( uievent *) event {cgpoint Pt = [[touches anyobject] locationinview: Self]; [self. points addobject: [nsvalue valuewithcgpoint: pt]; [self setneedsdisplay];}-(void) touchesended :( nsset *) touches withevent :( ui* event *) event {nsmutablearray * points_tmp = [[nsmutablearray alloc] initwitharray: Self. points]; If (self. points_all = nil) {self. points_all = [[nsarray alloc] initwithobjects: points_tmp, nil];} else {self. points_all = [self. points_all arraybyaddingobject: points_tmp] ;}}@ end

Viewcontroller. h

#import <UIKit/UIKit.h>@class TouchView;@interface ViewController : UIViewController{    TouchView *tv;}@end

Viewcontroller. m

#import "ViewController.h"#import "TouchView.h"@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad{    [super viewDidLoad];// Do any additional setup after loading the view, typically from a nib.    self.view.userInteractionEnabled = YES;      // TouchView *tv = [[TouchView alloc]initWithFrame:CGRectMake(0.0f, 0.0f, 260.0f, 260.0f)];    tv = [[TouchView alloc]initWithFrame:self.view.frame];    tv.backgroundColor = [UIColor blackColor];        [self.view addSubview:tv];        UISegmentedControl *seg = [[UISegmentedControl alloc] initWithItems:[@"White Red Blue Green Yellow" componentsSeparatedByString:@" "]];seg.segmentedControlStyle = UISegmentedControlSegmentCenter;    seg.tintColor = [UIColor blackColor];     seg.center = CGPointMake(self.view.center.x, (self.view.bounds.size.height - seg.bounds.size.height));     [self.view addSubview:seg];        [seg addTarget:self action:@selector(colorChange:) forControlEvents:UIControlEventValueChanged];}- (void)viewDidUnload{    [super viewDidUnload];    // Release any retained subviews of the main view.}- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation{    return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);}- (void) colorChange: (UISegmentedControl *) seg{switch ([seg selectedSegmentIndex]){case 0:             tv.paint_clr = [UIColor whiteColor];break;case 1:            tv.paint_clr = [UIColor redColor];break;case 2:tv.paint_clr = [UIColor blueColor];break;case 3:tv.paint_clr = [UIColor greenColor];break;case 4:tv.paint_clr = [UIColor yellowColor];break;default:break;}}@end