iOS應用開發——小畫板Demo

     還有很多功能可以加，記在這裡留著慢慢加吧。

代碼部分

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)rect{    // Drawing code    if ((!self.points) || (self.points.count < 2)) {        return;    }          context = UIGraphicsGetCurrentContext();    //設定畫筆粗細     CGContextSetLineWidth(context, 5.0f);    //設定畫筆顏色    //[[UIColor blueColor]set ];    // [paint_clr set];    //CGContextSetStrokeColorWithColor(context, [[UIColor blueColor]CGColor]);    CGContextSetStrokeColorWithColor(context, [paint_clr CGColor]);        //畫以前的軌跡    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);            }        }        //畫這次    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);    }    }//不支援多點觸摸- (BOOL) isMultipleTouchEnabled{    return NO;}//建立一個array，並且記錄初始ponit- (void) touchesBegan:(NSSet *) touches withEvent:(UIEvent *) event{    self.points = [NSMutableArray array];    CGPoint pt = [[touches anyObject] locationInView:self];    [self.points addObject:[NSValue valueWithCGPoint:pt]];}//移動過程中記錄這些points//調用setNeedsDisplay，會觸發drawRect方法的調用- (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:(UIEvent *)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