iphone - -[自定义窗口 HitTest :withEvent:] implementation to forward events

Question

我有一个自定义窗口(应该在所有内容之上，包括键盘)来显示覆盖物，类似于您在设备中按音量增大/减小按钮时看到的覆盖物。

所以我制作了一个自定义窗口 OverlayWindow 到目前为止一切正常，后面的窗口正常接收它们的事件。然而 hitTest:withEvent: 被多次调用，有时甚至返回 nil。我想知道这是否正常/正确？如果不是，我该如何解决？

// A small (WIDTH_MAX:100) window in the center of the screen. If it matters
const CGSize screenSize = [[UIScreen mainScreen] bounds].size; 
const CGRect rect = CGRectMake(((int)(screenSize.width - WIDTH_MAX)*0.5),
　　　　　　　((int)(screenSize.height - WIDTH_MAX)*0.5), WIDTH_MAX, WIDTH_MAX);
overlayWindow = [[CustomWindow alloc] initWithFrame:rect];
overlayWindow.windowLevel = UIWindowLevelStatusBar; //1000.0
overlayWindow.hidden = NO; // I don't need it to be the key (no makeKeyAndVisible)

‖

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
    // Find the front most window (with the highest window level) and
    // call this method on that window. It should will make the event be
    // forwarded to it

    // Situation1: This method is called twice (or even more, it depend
    // on the number of windows the app has) per event: Why? Is this the
    // *normal* behaviour?

    NSLog(@" ");
    NSLog(@"Point: %@ Event: %p\n", NSStringFromCGPoint(point), event);
    UIView *view = nil;
    if (CGRectContainsPoint(self.bounds, point)) {
        NSLog(@"inside window\n");
        NSArray *wins = [[UIApplication sharedApplication] windows];
        __block UIWindow *frontMostWin = nil;
        [wins enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
            NSLog(@"win: %@\n", obj);
            if ([obj windowLevel] >= [frontMostWin windowLevel] && obj != self) {
                frontMostWin = obj;
            }
        }];
        NSLog(@"frontMostWindow:%@\n finding a new view ...\n", frontMostWin);
        CGPoint p = [frontMostWindow convertPoint:point fromWindow:self];
        view = [frontMostWindow hitTest:p withEvent:event];

       // Situation2: sometimes view is nil here, Is that correct?
    }
    NSLog(@"resultView: %@\n", view);
    return view;
}

编辑:

我也注意到了

1. 如果 hitTest:withEvent: 总是返回 nil 它也有效。这仅在我调用 overlayWindow.hidden = NO;

时发生

2. 如果我调用 [overlayWindow makeKeyAndVisible] 在 hitTest:withEvent: 中返回 nil 并不总是有效。看来关键窗口需要正确实现 HitTest 方法？

我是否遗漏了一些关于事件转发的信息？

Answer 1

frontMostWindow 是否意味着 frontMostWin？

看起来即使我们只使用一个 UIWindow，hitTest:withEvent: 也会对其执行至少 2 次。所以，我想这是正常的。

您可以在

处收到 null

view = [frontMostWindow hitTest:p withEvent:event];

由于以下原因:

• frontMostWindow 本身为空(例如，如果您只有一个窗口)
• p 在 frontMostWindow 边界之外(例如，当 frontMostWindow 是键盘而您的触摸在其他地方时)
• frontMostWindow 的属性 userInteractionEnabled 设置为 NO；