如果你的UIView只是一个容器,需要覆盖drawrect吗?

时间:2010-06-03 00:34:33

标签: iphone uiview drawrect

根据Apple的文档,“如果子类是其他视图的容器,则子类不需要覆盖 - [UIView drawRect:]。”

我有一个自定义的UIView子类,它实际上只是其他视图的容器。然而,包含的观点并没有被绘制出来。以下是设置自定义UIView子类的相关代码:

- (id)initWithFrame:(CGRect)frame
{
    if ((self = [super initWithFrame:frame]))
    {
        // Consists of both an "on" light and an "off" light. We flick between the two depending upon our state.
        self.onLight = [[[LoyaltyCardNumberView alloc] initWithFrame:frame] autorelease];
        self.onLight.backgroundColor = [UIColor clearColor];
        self.onLight.on = YES;
        [self addSubview:self.onLight];

        self.offLight = [[[LoyaltyCardNumberView alloc] initWithFrame:frame] autorelease];
        self.offLight.backgroundColor = [UIColor clearColor];
        self.offLight.on = NO;
        [self addSubview:self.offLight];

        self.on = NO;
    }
    return self;
}

当我运行显示此自定义UIView的代码时,没有任何显示。但是当我添加一个drawRect方法时......

    - (void)drawRect:(CGRect)rect
    {
        [self.onLight drawRect:rect];
        [self.offLight drawRect:rect];
    }

...子视图显示。 (显然,这不是正确的做法,不仅因为它与文档所说的相反,而且因为它 - 总是 - 显示两个子视图,完全忽略了我的UIView中设置隐藏属性的其他代码。其中一个观点,它忽略了z排序等。)

无论如何,主要问题是:当我没有覆盖drawRect时,为什么不显示我的子视图:?

谢谢!

更新

为了确保问题不在我的自定义子视图中,我也添加了UILabel。所以代码如下:

- (id)initWithFrame:(CGRect)frame
{
    if ((self = [super initWithFrame:frame]))
    {
        // Consists of both an "on" light and an "off" light. We flick between the two depending upon our state.
        self.onLight = [[[LoyaltyCardNumberView alloc] initWithFrame:frame] autorelease];
        self.onLight.backgroundColor = [UIColor clearColor];
        self.onLight.on = YES;
        [self addSubview:self.onLight];

        self.offLight = [[[LoyaltyCardNumberView alloc] initWithFrame:frame] autorelease];
        self.offLight.backgroundColor = [UIColor clearColor];
        self.offLight.on = NO;
        [self addSubview:self.offLight];

        self.on = NO;

        UILabel* xLabel = [[[UILabel alloc] initWithFrame:frame] autorelease];
        xLabel.text = @"X";
        [self addSubview:xLabel];
    }
    return self;

“X”也不显示。

更新2:

这是调用我的自定义UIView(OffOnLightView)的代码:

            // Container for all of the OffOnLightViews...
            self.stampSuperView = [[[UIView alloc] initWithFrame:CGRectMake(0, 0, 100, 100)] autorelease];
            [self.view addSubview:self.stampSuperView];

            // Draw the stamps into the 'stamp superview'.
            NSInteger numberOfCardSpaces = (awardType == None) ? 3 : 10;
            for (NSInteger i = 1; i <= numberOfCardSpaces; i++)
            {
                OffOnLightView* newNumberView = [[[OffOnLightView alloc] initWithFrame:[self frameForStampWithOrdinal:i awardType:awardType]] autorelease];
                newNumberView.on = (i <= self.place.checkInCount.intValue);
                newNumberView.number = [NSString stringWithFormat:@"%d", i];
                [self.stampSuperView addSubview:newNumberView];
            }

2 个答案:

答案 0 :(得分:3)

您的子视图的框架应初始化为父uiview的边界。子视图位于不同的坐标系中,该坐标系相对于父级的框架。

self.onLight = [[[LoyaltyCardNumberView alloc] initWithFrame:self.bounds] autorelease];

答案 1 :(得分:2)

您不应该手动拨打-drawRect:。如果您需要强制重绘,请拨打-setNeedsDisplay

我将首先在您添加的两个子视图的NSLog()方法中进行调试(断点或-drawRect:),以确保它们实际执行绘图。

另请注意,您如何使两个子视图成为包含视图的完整大小(框架),并将其背景颜色设置为清除。我猜这是故意的,但它们可能正在显示,但由于它们具有透明的背景,你只是看不到任何东西。