[iOS]绘图、写字（重写UIView）

本文主要是介绍[iOS]绘图、写字（重写UIView），希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

绘图、写字（重写UIView）

Demo:http://download.csdn.net/detail/u012881779/8667943

1.创建一个继承于UIView的类：DrawView

2.创建一个继承于UIViewController的类：ViewController

再在ViewController的Xib中添加UIView控件，设置UIView继承于DrawView

#import <UIKit/UIKit.h>@interface DrawView : UIView
@property (strong, nonatomic) NSMutableArray *mArrPoint;
@property (strong, nonatomic) NSMutableArray *savePoint;
@property (strong, nonatomic) NSMutableArray *displayPoint;
@property (strong, nonatomic) NSValue *lastValue;// 清空画布
- (void)cleanDrawView;@end#import "DrawView.h"@implementation DrawView
@synthesize mArrPoint = _mArrPoint;
@synthesize savePoint = _savePoint;
@synthesize displayPoint = _displayPoint;
@synthesize lastValue = _lastValue;- (id)initWithFrame:(CGRect)frame {self = [super initWithFrame:frame];if (self) {// Initialization code}return self;
}- (void)drawRect:(CGRect)rect {// 存储点不为空时往下执行if (_mArrPoint) {// 1.绘图上下文CGContextRef context = UIGraphicsGetCurrentContext();/*从UI上取得当前笔画，并存储1）、把组成每一笔画的点存储在一个数组（savePoint）2）、再把每一画打包成一个对象，存储到另一个数组(displayPoint)*/if (!_savePoint) {_savePoint = [[NSMutableArray alloc] init];}_savePoint = _mArrPoint;if (!_displayPoint) {_displayPoint = [[NSMutableArray alloc] init];}[_displayPoint addObject:_savePoint];// 2.连接各点构成线，双重循环for (int i = 0 ; i < [_displayPoint count] ; i ++) {NSMutableArray *tempArr = [_displayPoint objectAtIndex:i];// 书写每一笔画时，重新设置起始点CGPoint startPoint = [[tempArr objectAtIndex:0 ] CGPointValue];CGContextMoveToPoint(context, startPoint.x, startPoint.y);for (int j = 0 ; j < [tempArr count] ; j ++) {CGContextAddLineToPoint(context,[[tempArr objectAtIndex:j] CGPointValue].x,[[tempArr objectAtIndex:j] CGPointValue].y);}}// 3设置画笔属性，宽度，颜色[[UIColor greenColor] set];CGContextSetLineWidth(context, 5);CGContextStrokePath(context);}
}// 清空画布
- (void)cleanDrawView {_mArrPoint = nil;_savePoint = nil;_displayPoint = nil;[self setNeedsDisplay];
}#pragma mark UIResponder
// 开始触摸
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {_mArrPoint = nil;NSLog(@"touchesBegan");
}// 触摸移动，不断监听一次有效的Touch移动
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {if (!_mArrPoint) {_mArrPoint = [[NSMutableArray alloc] init];}CGPoint touchPoint = [[touches anyObject] locationInView:self];[_mArrPoint addObject:[NSValue valueWithCGPoint: touchPoint]];[self setNeedsDisplay];NSLog(@"touchesMoved");
}// 触摸事件结束
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {NSLog(@"touchesEnded");
}// 触摸事件 取消，比如来电话打断
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {NSLog(@"touchesCancelled");
}/*而这几个方法被调用时，正好对应了UITouch类中phase属性的4个枚举值。上面的四个事件方法，在开发过程中并不要求全部实现，可以根据需要重写特定的方法。对于这4个方法都有两个相同的参数：NSSet类型的touches和UIEvent类型的event。其中touches表示触摸产生的所有UITouch对象，而event表示特定的事件。因为UIEvent包含了整个触摸过程中所有的触摸对象因此可以调用allTouches方法获取该事件内所有的触摸对象，也可以调用touchesForVIew：或者touchesForWindows：取出特定视图或者窗口上的触摸对象。在这几个事件中，都可以拿到触摸对象然后根据其位置，状态，时间属性做逻辑处理。*/@end

示图：