Question

如果你想将UIView从一个视图移动到另一个视图（例如，通过segue“转移”UIView），这可以完美地运行......

-(void)takeover:(UIView*)peel
    {
    // transfer "ownership" of a view from wherever it is now, to self.
    // keep the position correct.

    CGPoint centerInWC = [peel.superview convertPoint:peel.center toView:nil];
    [self addSubview:peel];
    CGPoint centerInMyViewCoords = [self convertPoint:centerInWC fromView:nil];
    peel.center = centerInMyViewCoords;
    }

（请参阅toView的文档：and fromView：... "If view is nil, this method instead converts to window base coordinates."）

这是输出..

2014-07-07 19:59:04.273  before .... actual position ... {87, 107}
2014-07-07 19:59:04.278  centerInWC is ... {87, 107}
2014-07-07 19:59:04.278  centerInMyViewCoords is ... {87, 107}

没问题。一切都很棒。

如何使用主窗口，所以keyWindow ??

现在，您认为以下内容也有效：

-(void)takeover:(UIView*)peel
    {
    //let's try using "main window" coords...

    UIWindow *mainWindow = [[UIApplication sharedApplication] keyWindow];

    CGPoint cWC = [mainWindow convertPoint:peel.center fromView:peel.superview];
    [self addSubview:peel];
    CGPoint c = [self convertPoint:cWC fromView:mainWindow];
    peel.center = c;
    }

实际上它不起作用！

每一次，您都会获得一半实际正确值的值。

这是输出......

2014-07-07 19:59:04.273  before .... actual position ... {87, 107}
2014-07-07 19:59:04.278  cWC is ... {43.5, 53.5}
2014-07-07 19:59:04.278  c is ... {43.5, 53.5}

有人知道解释吗？干杯...

keyWindow职位是＆＃34;一半大＆＃34;奇怪的问题

0 个答案: