ios - UIView 未被调用

Question

还有许多其他问题，但似乎没有一个解决方案适合我。我是 iOS 的新手 - 目前正在处理 Big Nerd Ranch iOS Programming 一书中的问题。

我发现的大多数 SO 都说问题最终是 userInteractionEnabled = YES was missing。或者 View 的背景设置为透明。但是移除透明背景并设置 userInteractionEnabled = YES 并没有导致事件触发。有什么想法我想念的吗？

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:

View 调试器的屏幕截图

Answer 1

您正在将 BNRHypnosisView 添加为窗口的 subview 。稍后，当窗口即将出现在屏幕上时，它会将其 Root View Controller 的 View 作为另一个 subview 添加到您的催眠 View 前面。您可以在 View 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。列表后面的 View 比列表前面的 View “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;
}