用UITouchView创建简单画板.点击颜色改变画笔颜色,有撤销键(UIButton简化后)

MainViewControl.m

#import "MainViewController.h"#import "TouchView.h"@interface MainViewController ()@end@implementation MainViewController- (void)dealloc{    [super dealloc];}- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil{    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];    if (self) {        // Custom initialization    }    return self;}- (void)viewDidLoad{    [super viewDidLoad];    // Do any additional setup after loading the view.        TouchView * aView = [[TouchView alloc] initWithFrame:CGRectMake(20, 20, 280, 440)];    [aView setBackgroundColor:[UIColor whiteColor]];    [self.view addSubview:aView];    [aView release];}- (void)didReceiveMemoryWarning{    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}@end

TouchView.h

#import <UIKit/UIKit.h>@interface TouchView : UIView{    //所有在.h里声明的容器类变量,只能在.m方法里初始化        NSMutableArray * _pointArray;    //建立可变数组,存数第一笔所有点组成的线    NSMutableArray * _lineArray;    //存储 改变颜色    UIColor * _color;}@end

#import "TouchView.h"@implementation TouchView- (void) dealloc{    [_pointArray release];    _pointArray= nil;    [_lineArray release];    _lineArray = nil;    [super dealloc];}- (id)initWithFrame:(CGRect)frame{    self = [super initWithFrame:frame];    if (self) {        // Initialization code        _pointArray = [[NSMutableArray alloc] init];        _lineArray = [[NSMutableArray alloc] init];        _color = [UIColor blackColor];    }          NSArray * arr = [NSArray arrayWithObjects:[UIColor redColor],[UIColor magentaColor],[UIColor yellowColor],[UIColor orangeColor],[UIColor greenColor],[UIColor cyanColor],[UIColor blueColor],[UIColor purpleColor],[UIColor brownColor],[UIColor grayColor],[UIColor blackColor],[UIColor clearColor], nil];        int i = 0;    for (UIColor * color in arr) {        UIButton * abutton = [[UIButton alloc] initWithFrame:CGRectMake(23*i+2, 417, 23, 23)];        [abutton setBackgroundColor:color];        [abutton addTarget:self action:@selector(buttonAction:) forControlEvents:UIControlEventTouchUpInside];        if (color == [UIColor clearColor]) {            [abutton setTitle:@"c" forState:UIControlStateNormal];            [abutton setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];            //Button不能设置边框 ,所以要从底层调用,用.layer            [abutton.layer setBorderWidth:1];            //UIColor是对象类型,边框颜色需要CGColorRef类型的结构体,(只读的属性).所以后面要.CGColor            [abutton.layer setBorderColor:[UIColor redColor].CGColor];        }                [self addSubview:abutton];        [abutton release];                i++;    }     return self;

}

        if ([button.currentTitle isEqualToString:@"c"]) {                [_lineArray removeLastObject];    }else{        _color = button.backgroundColor;    }    [self setNeedsDisplay];    }- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{    //清空//    [_pointArray removeAllObjects];    //获得集合里的元素    UITouch * touch = [touches anyObject];    //获得起始点坐标    CGPoint point = [touch locationInView:self];    //结构体转换为对象,全部用NSValue   CGPoint是结构体  转换为 对象    NSValue * value = [NSValue valueWithCGPoint:point];    //把元素存入数组//    [_pointArray addObject:value];    //局部变量要用便利构造器  不用释放 系统自动release    NSMutableArray * points = [NSMutableArray array];//创建火车头,也就是数组线    //放入第一个椅子    [points addObject:value];    //把车厢挂到火车头上//    [_lineArray addObject:points];    //其他的在move中添加        NSMutableDictionary * dic = [[NSMutableDictionary alloc] initWithObjectsAndKeys:_color,@"color",points,@"point", nil];    //把字典传入数组里    [_lineArray addObject:dic];            }- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{    UITouch * touch = [touches anyObject];    CGPoint point = [touch locationInView:self];    NSValue * value = [NSValue valueWithCGPoint:point];//    [_pointArray addObject:value];    //通过最后一个元素,取数组//    NSMutableArray * points = [_lineArray lastObject];    //把移动的坐标放到数组中//    [points addObject:value];        NSMutableDictionary * dic = [_lineArray lastObject];    NSMutableArray * points = [dic objectForKey:@"point"];    //把对象添加到数组里    [points addObject:value];        //调用下面绘画的方法    [self setNeedsDisplay];}- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{    }- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event{    }// Only override drawRect: if you perform custom drawing.// An empty implementation adversely affects performance during animation.- (void)drawRect:(CGRect)rect{    // Drawing code    //获得上下文    CGContextRef context = UIGraphicsGetCurrentContext();        for (NSMutableDictionary * dic in _lineArray) {        //获得起始点坐标        NSValue * firstValue = [[dic objectForKey:@"point"] firstObject];        //转换        CGPoint firstPoint = [firstValue CGPointValue];        UIColor * c = [dic objectForKey:@"color"];        CGContextSetStrokeColorWithColor(context, c.CGColor);        //起始点        CGContextMoveToPoint(context, firstPoint.x, firstPoint.y);                for (NSValue * value in [dic objectForKey:@"point"]) {                        CGPoint currentPoint = [value CGPointValue];            //添加到线上            CGContextAddLineToPoint(context, currentPoint.x, currentPoint.y);                    }                CGContextStrokePath(context);    }    }@end