需求 - 23 - 帶朦朧的遮罩效果 - 2

上面提到一個朦朧遮罩的實現方式

接下來介紹另外一種實現，利用iOS7所提供的 UIVisualEffectView 來實現（自行百度一下這個類的介紹）

並且前提先要了解清楚：

- (nullable UIView *)hitTest:(CGPoint)point withEvent:(nullable UIEvent *)event;

hitTest這個方法結合UIWindow，經常來配合使用，比較多的場景有置頂操作，朦朧遮罩層的實現等等

最重要的功能是這個方法可以穿透視圖層，這樣你可以鎖定你要響應的對象，這裏記住這個話，以後大大有所用

一、定義UIWindow類，作爲響應罩面：

#import <UIKit/UIKit.h>

@interface OverheadView : UIWindow

@end

實現：

#import "OverheadView.h"

@implementation OverheadView

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
    id obj = [super hitTest:point withEvent:event];
    if ([obj isKindOfClass:NSClassFromString(@"HyRoundMenuView")]) {
        return obj;
    }

    return nil;
}

@end

稍微解釋一下：出現朦朧遮罩面時候，返回obj響應對象，否則，穿透該window層級（無視它）

二、定義遮罩層視圖

#import <UIKit/UIKit.h>
#import "HyRoundMenuModel.h"

typedef enum : NSUInteger
{
    HyRoundMenuViewBackgroundViewTypeBlur NS_ENUM_AVAILABLE_IOS(9_0) = 0,
    HyRoundMenuViewBackgroundViewTypeCustomColors = 1,
}   HyRoundMenuViewBackgroundViewType;


@interface HyRoundMenuView : UIControl

@property (nonatomic, assign) UIBlurEffectStyle blurEffectStyle;

@property (nonatomic, nonnull, copy  ) UIColor *customBackgroundViewColor;

@property (nonatomic, assign) HyRoundMenuViewBackgroundViewType backgroundViewType;

+ (__nonnull instancetype) shareInstance;

@end

實現：

#import "HyRoundMenuView.h"
#import "OverheadView.h"

#define IH_DEVICE_HEIGHT    [[UIScreen mainScreen] bounds].size.height
#define IH_DEVICE_WIDTH     [[UIScreen mainScreen] bounds].size.width

@interface HyRoundMenuView ()

@property (nonatomic, nonnull, strong) UIView *backgroundView;

@property (nonatomic, nonnull, strong) OverheadView *topView;

@end

@implementation HyRoundMenuView

static HyRoundMenuView* _instance = nil;     
+(instancetype) shareInstance
{
    static dispatch_once_t onceToken ;
    dispatch_once(&onceToken, ^{
        _instance = [[super allocWithZone:NULL] init] ;
    }) ;
    return _instance ;
}

- (instancetype) init
{
    self = [super init];
    
    if (self) { [self initUI]; }
    
    return self;
}

- (void)initUI
{
    self.frame = [UIScreen mainScreen].bounds;
    self.backgroundColor = [UIColor clearColor];

    self.userInteractionEnabled = true;
    
    _blurEffectStyle    = UIBlurEffectStyleLight;
    _backgroundViewType = HyRoundMenuViewBackgroundViewTypeBlur;
    
    //backgroundView
    if (!_backgroundView) {
        _backgroundView = [[UIVisualEffectView alloc] initWithFrame:[UIScreen mainScreen].bounds];
        _backgroundView.hidden = YES;
        _backgroundView.backgroundColor = [UIColor clearColor];
        ((UIVisualEffectView *)_backgroundView).effect = nil;
    }
    [_backgroundView setFrame:self.bounds];
    
    [self addSuperView];

}


- (void)addSuperView
{
    _topView = [[OverheadView alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    _topView.backgroundColor = [UIColor colorWithWhite:1 alpha:0];
    _topView.windowLevel = UIWindowLevelAlert;
    _topView.hidden = NO;
    _topView.alpha = 1;
    [_topView makeKeyAndVisible];
    UIViewController *vc = [UIViewController new];
    _topView.rootViewController = vc;
    [_topView addSubview:_backgroundView];
    [_topView addSubview:self];
}


- (void)startBackgroundViewAnimationIsOpen:(BOOL)isMasking
{
    if (isMasking)
    {
        ((UIVisualEffectView *)_backgroundView).hidden = (_backgroundViewType == HyRoundMenuViewBackgroundViewTypeCustomColors);
        [UIView animateWithDuration:0.3f animations:^{//customBackgroundViewColor
            if (_backgroundViewType != HyRoundMenuViewBackgroundViewTypeCustomColors) ((UIVisualEffectView *)_backgroundView).effect = [UIBlurEffect effectWithStyle:_blurEffectStyle];
            if (_backgroundViewType == HyRoundMenuViewBackgroundViewTypeCustomColors) self.backgroundColor = _customBackgroundViewColor;
        }];
    }
    else
    {
        [UIView animateWithDuration:0.3f animations:^{
            if (_backgroundViewType != HyRoundMenuViewBackgroundViewTypeCustomColors) ((UIVisualEffectView *)_backgroundView).effect = nil;
            if (_backgroundViewType == HyRoundMenuViewBackgroundViewTypeCustomColors) self.backgroundColor = [UIColor clearColor];
        } completion:^(BOOL finished) {
            _backgroundView.hidden = _backgroundViewType == HyRoundMenuViewBackgroundViewTypeCustomColors;
        }];
    }
}


static BOOL isMasking = false;

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

    isMasking = !isMasking;
    
    [self startBackgroundViewAnimationIsOpen:isMasking];
}


- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
    id obj = [super hitTest:point withEvent:event];

    return obj;
}

@end

具體實現，也沒什麼好說的，千萬記得hitTest在這裏面的功用就行了，其實遮罩層的hitTest方法並沒有達到什麼作用，但是爲什麼保留呢？

因爲這個方法在“過濾”的效果非常好用，以後在別的需求會講到這個方法的作用

實現是轉載學習於：

https://github.com/wwdc14/HyRoundMenuView