解析UIControl

解析UIControl

从下图可以看出,UIControl继承自UIView,添加了响应事件功能.

UIButton之所以能响应各种各样的事件是因为继承自UIControl

使用UIControl可以精确的控制按钮事件,我用定制UIControlEventValueChanged来进行说明.

YXControl.h + YXControl.m

//

//  YXControl.h

//  UIControl

//

//  Copyright (c) 2014年 Y.X. All rights reserved.

//

#import <UIKit/UIKit.h>

@interface YXControl : UIControl

@property (nonatomic, strong) UIImage *yesImage;

@property (nonatomic, strong) UIImage *noImage;

- (void)exchange;

@end

//

//  YXControl.m

//  UIControl

//

//  Copyright (c) 2014年 Y.X. All rights reserved.

//

#import "YXControl.h"

@interface YXControl ()

@property (nonatomic, strong) UIImageView *YesImageView;

@property (nonatomic, strong) UIImageView *NoImageView;

@end

@implementation YXControl

#pragma mark - 重写 getter setter 方法

@synthesize yesImage = _yesImage;

@synthesize noImage  = _noImage;

- (UIImage *)yesImage

{

    return _yesImage;

}

- (void)setYesImage:(UIImage *)yesImage

{

    _yesImage = yesImage;

    _YesImageView.image = yesImage;

}

- (UIImage *)noImage

{

    return _noImage;

}

- (void)setNoImage:(UIImage *)noImage

{

    _noImage = noImage;

    _NoImageView.image = noImage;

}

#pragma mark - 初始化

- (id)initWithFrame:(CGRect)frame

{

    self = [super initWithFrame:frame];

    if (self)

    {

        _YesImageView = [[UIImageView alloc] initWithFrame:frame];

        _NoImageView  = [[UIImageView alloc] initWithFrame:frame];

        [self addSubview:_YesImageView];

        [self addSubview:_NoImageView];

    }

    return self;

}

#pragma mark - UIControl事件

- (BOOL)beginTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event

{

    // 获取触摸点坐标

    CGPoint p = [touch locationInView:self];

    NSLog(@"begin    %@", NSStringFromCGPoint(p));

    return YES;

}

- (BOOL)continueTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event

{

    // 获取触摸点坐标

    CGPoint p = [touch locationInView:self];

    NSLog(@"continue %@", NSStringFromCGPoint(p));

    return YES;

}

- (void)endTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event

{

    // 获取触摸点坐标

    CGPoint p = [touch locationInView:self];

    NSLog(@"end      %@", NSStringFromCGPoint(p));

    // 判断触摸点是否超出了这个view的范围

    if (p.x >=  && p.x <= self.bounds.size.width &&

        p.y >=  && p.y <= self.bounds.size.height)

    {

        // 发送事件

        [self sendActionsForControlEvents:UIControlEventValueChanged];

    }

}

- (void)cancelTrackingWithEvent:(UIEvent *)event

{

}

- (void)exchange

{

    [self bringSubviewToFront:self.subviews[]];

}

@end

用于测试用的图片

结果如图下图所示:

//

//  RootViewController.m

//  UIControl

//

//  Copyright (c) 2014年 Y.X. All rights reserved.

//

#import "RootViewController.h"

#import "YXControl.h"

@interface RootViewController ()

@end

@implementation RootViewController

- (void)viewDidLoad

{

    [super viewDidLoad];

    // 初始化UIControl

    YXControl *controlView      = [[YXControl alloc] initWithFrame:CGRectMake(, , , )];

    controlView.backgroundColor = [UIColor blackColor];

    controlView.center          = self.view.center;

    controlView.yesImage        = [UIImage imageNamed:@"yes"];

    controlView.noImage         = [UIImage imageNamed:@"no"];

    [self.view addSubview:controlView];

    // 添加响应事件

    [controlView addTarget:self

                    action:@selector(controlEvent:)

          forControlEvents:UIControlEventValueChanged];

}

- (void)controlEvent:(YXControl *)control

{

    [control exchange];

}

@end

以下三个方法非常重要:

beginTrackingWithTouch:        触摸事件刚刚开始时执行(1次)

continueTrackingWithTouch:   滑动手指后将会一直执行(多次)

endTrackingWithTouch:          松开手指后执行(1次)

以下两个地方也是需要注意的哦:

1. 发送UIControlEventValueChanged事件

2. 注册对应的UIControlEventValueChanged事件

只有这样子,两者之间才能通过addTarget:action:forControlEvents:联系起来.

以下这个小细节也是非常令人意外的,UIControlEventValueChanged这个值是非常独特的呢.

如果使用UIControlEventTouchUpInside,这个事件是UIControl自动发的,不需要你管哦(也就是说不需要你执行sendActionsForControlEvents:)