ios--UI高级用事件实现简单截图功能

ViewController.m

@interface ViewController (){

    MyTouchView *touchView;

}

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    

    touchView = [[MyTouchView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height)];

    touchView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"liushishi"]];

    touchView.userInteractionEnabled = YES;

    touchView.multipleTouchEnabled = YES;

    [self.view addSubview:touchView];  

}

myTouchView.m

-(instancetype)initWithFrame:(CGRect)frame{

    self = [super initWithFrame:frame];

        if (self) {

            imageV = [[UIView alloc] init];

            imageV.backgroundColor = [UIColor blackColor];

            imageV.alpha = 0.5;

            [self addSubview:imageV];

    }

    return self;

}

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{

    UITouch *touch = [touches anyObject];

    _startPoint = [touch locationInView:self];

    

}

-(void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{

    UITouch *touch = [touches anyObject];

    _endPoint = [touch locationInView:self];

}

-(void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{

    

    CGFloat width = _endPoint.x - _startPoint.x;

    CGFloat height = _endPoint.y - _startPoint.y;

    

    CGRect area = CGRectMake(_startPoint.x, _startPoint.y, width, height);

    

    imageV.frame = area;

    

}

运行结果：

说明：这里没有使用上下文，所以截图之后没有进行保存功能，只是写了一个简单用事件实现截图的代码。