［自定义组件之二］两种方式改造UIView

淩亂°似流年 2022-08-20 12:18 144阅读 0赞

#import <UIKit/UIKit.h>
    @class MyUIViewWithDelegate;
    @class MYUIViewWithEvent;
    
    @protocol UIViewDrawRectDelegate <NSObject>
    @optional
    -(void)beforeDrawRect:(CGRect)rect;
    -(void)AfterDrawRect:(CGRect)rect;
    @end
    
    @interface ViewController : UIViewController<UIViewDrawRectDelegate>
    @property (strong, nonatomic) IBOutlet MyUIViewWithDelegate *ViewWithDelegate;
    @property (strong, nonatomic) IBOutlet MYUIViewWithEvent *ViewWithEvent;
    
    @end
    
    #pragma mark - MyUIViewWithDelegate 使用代理＋继承方式
    @interface MyUIViewWithDelegate :UIView
    @property (nonatomic,assign) id <UIViewDrawRectDelegate> delegate;
    -(void) drawRect:(CGRect)rect;
    @end
    
    #pragma mark - MYUIViewWithEvent 使用block＋继承的方式（delphi写法）
    typedef void (^UIViewDrawRectEvent)(CGRect, id);
    @interface MYUIViewWithEvent:UIView
    @property (nonatomic,copy) UIViewDrawRectEvent BeforeDrawEVent;
    @property (nonatomic,copy) UIViewDrawRectEvent AfterDrawEVent;
    -(void)drawRect:(CGRect)rect;
    @end

#import "ViewController.h"
    
    
    @interface ViewController ()
    
    @end
    
    @implementation ViewController
    {
        float _curX;
        float _curY;
    }
    -(void)beforeDrawRect:(CGRect)rect
    {
        CGContextRef ctx = UIGraphicsGetCurrentContext();
        CGContextSetFillColorWithColor(ctx, [[UIColor redColor] CGColor]);
        CGContextFillEllipseInRect(ctx, CGRectMake(_curX-15, _curY - 15, 30, 30));
    }
    - (void)viewDidLoad {
        [super viewDidLoad];
        self.ViewWithDelegate.delegate = self;
        self.ViewWithEvent.BeforeDrawEVent = ^(CGRect rect, id sender)
        {
            CGContextRef ctx = UIGraphicsGetCurrentContext();
            CGContextSetFillColorWithColor(ctx, [[UIColor greenColor] CGColor]);
            CGContextFillEllipseInRect(ctx, CGRectMake(_curX-15, _curY - 15, 30, 30));
        };
    }
    
    - (void)didReceiveMemoryWarning {
        [super didReceiveMemoryWarning];
        // Dispose of any resources that can be recreated.
    }
    
    -(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
    {
        UITouch* touch = [touches anyObject];
        CGPoint point = [touch locationInView:self.view];
        if ([self.ViewWithDelegate pointInside:point withEvent:event]) {
            _curX = point.x;
            _curY = point.y;
            [self.ViewWithDelegate setNeedsDisplay];
        }
        else{
            _curX = point.x;
            _curY = point.y - self.ViewWithDelegate.frame.size.height;
            [self.ViewWithEvent setNeedsDisplay];
        }
    }
    @end
    
    
    #pragma mark - MyUIViewWithDelegate 使用代理＋继承方式
    @implementation MyUIViewWithDelegate
    -(void)drawRect:(CGRect)rect
    {
        if (self.delegate && [self.delegate respondsToSelector:@selector(beforeDrawRect:)]) {
            [self.delegate beforeDrawRect:rect];
        }
        [super drawRect:rect];
        if (self.delegate && [self.delegate respondsToSelector:@selector(AfterDrawRect:)]) {
            [self.delegate AfterDrawRect:rect];
        }
    }
    @end
    
    #pragma mark - MYUIViewWithEvent 使用block＋继承的方式（delphi写法）
    @implementation  MYUIViewWithEvent
    
    -(void)drawRect:(CGRect)rect
    {
        if (self.BeforeDrawEVent) {
            self.BeforeDrawEVent(rect,self);
        }
        [super drawRect:rect];
        if (self.AfterDrawEVent) {
            self.AfterDrawEVent(rect,self);
        }
    }
    @end

总结下吧：

1，利用了代理模式和block方式覆盖了uiview的drawRect，对其进行了扩展。

2，因类别不能有自己变量（runtime的没试验），都采取了继承方式。

3，delphi的后期版本能直接写成uiview:path.uiview的方式，比类别功能强大，能声明变量。![Center][]

[Center]: /images/20220731/9e314d289fd14986a029565944c68c7d.png