UIView 未被调用

Question

还有许多其他问题，但 none 的解决方案似乎对我有用。我是 iOS 的新手 - 目前正在处理 Big Nerd Ranch iOS 编程书籍中的一个问题。

我发现的大多数 SO 都说问题最终被 userInteractionEnabled = YES 遗漏了。或者视图的背景设置为 transparent。但是删除透明背景并设置 userInteractionEnabled = YES 并没有导致事件触发。知道我遗漏了什么吗？

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;
}

应用截图：

视图调试器的屏幕截图

Answer 1

您正在将 BNRHypnosisView 添加为 window 的子视图。稍后，当 window 即将出现在屏幕上时，它会将其根视图控制器的视图作为另一个子视图添加到您的催眠视图前面。您可以在视图层次结构中看到这一点，它在您的 BNRHypnosisView 之后显示一个普通的 UIView。列表中靠后的视图比列表中靠前的视图“在顶部”或“更靠近屏幕”。

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;
}

UIView 未被调用

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