UIView没有得到touchesbegan的称呼

Question

还有其他一些问题，但没有一个解决方案对我有用。我对iOS很陌生 - 目前正在研究Big Nerd Ranch iOS编程书中的一个问题。

我发现的大多数SO都说这个问题最终被遗忘userInteractionEnabled = YES。或者视图的背景设置为transparent。但是删除透明背景并设置userInteractionEnabled = YES并不会导致事件触发。我缺少什么想法？

AppDelegate.m：

#import "AppDelegate.h"
#import "BNRHypnosisView.h"
#import "ViewController.h"

@interface AppDelegate ()

@end

@implementation AppDelegate


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

    CGRect firstFrame = self.window.bounds;

    BNRHypnosisView *firstView = [[BNRHypnosisView alloc] initWithFrame:firstFrame];
    firstView.userInteractionEnabled = YES;

    ViewController *controller = [[ViewController alloc] init];
    [self.window setRootViewController:controller];
    [self.window addSubview:firstView];

    self.window.backgroundColor = [UIColor whiteColor];

    [self.window makeKeyAndVisible];

    return YES;
}

BNRHypnosisView.m：

#import "BNRHypnosisView.h"

@interface BNRHypnosisView()

@property (strong, nonatomic) UIColor *circleColor;

@end

@implementation BNRHypnosisView
-(void)drawRect:(CGRect)rect {
    CGRect bounds = self.bounds;

    CGPoint center;
    center.x = bounds.origin.x + bounds.size.width / 2.0;
    center.y = bounds.origin.y + bounds.size.height / 2.0;

    float maxRadius = hypot(bounds.size.width, bounds.size.height) / 2.0;
    UIBezierPath *path = [[UIBezierPath alloc] init];

    for (float currentRadius = maxRadius; currentRadius > 0; currentRadius -=20) {
        [path moveToPoint:CGPointMake(center.x + currentRadius, center.y)];

        [path addArcWithCenter:center radius:currentRadius startAngle:0.0 endAngle:M_PI * 2.0 clockwise:YES];
    }

    path.lineWidth = 10;

    [self.circleColor setStroke];

    [path stroke];
}

-(instancetype)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        self.backgroundColor = [UIColor clearColor];
        self.circleColor = [UIColor lightGrayColor];
    }
    return self;
}

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    NSLog(@"%@ was touched", self);

    float red = (arc4random() % 100) / 100.0;
    float green = (arc4random() % 100) / 100.0;
    float blue = (arc4random() % 100) / 100.0;

    UIColor *randomColor = [UIColor colorWithRed:red green:green blue:blue alpha:1.0];

    self.circleColor = randomColor;
}

app的屏幕截图：

查看调试器

的屏幕截图

Answer 1

您正在添加BNRHypnosisView作为窗口的子视图。稍后，当窗口即将出现在屏幕上时，它会在催眠视图前面将其根视图控制器的视图添加为另一个子视图。您可以在视图层次结构中看到此信息，在UIView之后显示普通BNRHypnosisView。列表中稍后的视图是“在屏幕之上”或“比屏幕更靠近”列表中较早的视图。

试试这个：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.window.backgroundColor = [UIColor whiteColor];

    ViewController *controller = [[ViewController alloc] init];
    [self.window setRootViewController:controller];

    BNRHypnosisView *firstView = [[BNRHypnosisView alloc] initWithFrame:controller.view.bounds];
    firstView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
    firstView.userInteractionEnabled = YES;
    [controller.view addSubview:firstView];

    [self.window makeKeyAndVisible];
    return YES;
}