macos - cocoa 自动布局 : insert (and remove) view programmatically at runtime

Question

我对 Cocoa 自动布局有一些问题。我有一个窗口，并(以编程方式)添加一个 NSTableView (及其 NSScrollView)。到现在为止一切都还好。我可以调整窗口的大小，并且表格的大小也可以正确调整。这是我使用的代码。

MyListViewController *viewController = [[MyListViewController alloc] initWithNibName:@"ListView" bundle:nil];

[self.mainContentView addSubview:viewController.view];
[viewController.view setTranslatesAutoresizingMaskIntoConstraints:NO];

[self.mainContentView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[insertedView]|"
                                                                                 options:0
                                                                                 metrics:nil
                                                                                   views:@{@"insertedView" :viewController.view}]];
NSArray *verticalConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|[insertedView]|"
                                                                           options:0
                                                                           metrics:nil
                                                                             views:@{@"insertedView" :viewController.view}];

[self.mainContentView addConstraints:verticalConstraints];

现在..我想在运行时添加(和删除)另一个位于表格顶部的 View 。该 View 是一个带有 NSScrollView 的 NSPredicateEditor。需要明确的是:当您在搜索字段中键入内容并且具有可能的搜索选项的 View 出现在主窗口中时，我试图实现与 Finder 相同的行为。

我是这样处理的:

AdvancedFilterViewController *viewController = [[AdvancedFilterViewController alloc] initWithNibName:@"AdvancedFilterView" bundle:nil];

[self.mainContentView addSubview:viewController.view];
[viewController.view setTranslatesAutoresizingMaskIntoConstraints:NO];

[self.mainContentView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[insertedView]|"
                                                                             options:0
                                                                             metrics:nil
                                                                               views:@{@"insertedView" :viewController.view}]];
[self.mainContentView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[insertedView(<=225)][prevView]|" // >= size of one row, <= size of 8 + 1 rows
                                                                             options:0
                                                                             metrics:nil
                                                                               views:@{@"insertedView" :viewController.view, @"prevView" : self.listView.view}]];

我希望至少有一行谓词(25 点)可见。当用户按下加号按钮时，更多 View 开始出现(并且 ScrollView 应该调整其大小)。在几行之后(我决定是 9 行)，滚动条应该开始出现，窗口中的主视图应该停止缩小。

问题是，当我插入过滤器 View 时，它的大小几乎为零(例如 1 点)。或者，如果我添加最小大小为 25 点， View 是可见的，但添加行只会增加 ScrollView 的“内部大小”，因此会出现滚动条(但 ScrollView 不会增大，也不会使 ListView 缩小) .

我希望我正确地解释了这个问题。

编辑:

从我实现委托(delegate)的答案中汲取灵感:

- (void)ruleEditorRowsDidChange:(NSNotification *)notification
{
    //handle resizing of the view
    [self.predicateEditorHeight setConstant:[self.predicateEditor numberOfRows] * self.predicateEditor.rowHeight];
}

其中 self.predicateEditorHeight 是对 NSScrollView 高度进行约束的 IBOutlet。然后，在封闭的 NSWindowController 中，当我添加谓词编辑器 View 时，我还添加了对 NSTableView 相对于谓词 View 的比例的约束。这样(因为我将其设置为 0.3) ScrollView 可以增长到某个点，然后，在那之后，它必须使用其滚动条。

我对限制仍有一些问题:例如，当我在编辑器中添加太多行时，我得到

2014-04-26 09:38:27.769 MyApp[2531:303] Unable to simultaneously satisfy constraints:
(
    "<NSLayoutConstraint:0x60000029dc40 V:[NSView:0x60000013fb80]-(0)-|   (Names: '|':NSView:0x60000013e500 )>",
    "<NSLayoutConstraint:0x60000029dbf0 V:[NSView:0x600000320b40]-(0)-[NSView:0x60000013fb80]>",
    "<NSLayoutConstraint:0x60000029dc90 NSView:0x60000013fb80.height >= 0.3*NSView:0x600000320b40.height>",
    "<NSAutoresizingMaskLayoutConstraint:0x608000288b60 h=--& v=--& V:[NSView:0x60000013e500(360)]>",
    "<NSLayoutConstraint:0x60000029dba0 V:|-(0)-[NSView:0x600000320b40]   (Names: '|':NSView:0x60000013e500 )>",
    "<NSLayoutConstraint:0x60000029d1a0 V:[NSView:0x600000320f00(275)]>",
    "<NSLayoutConstraint:0x60000029d420 V:[NSView:0x600000320f00]-(0)-|   (Names: '|':NSView:0x600000320b40 )>",
    "<NSLayoutConstraint:0x60000029d510 V:[NSView:0x600000320dc0]-(0)-[NSView:0x600000320f00]>",
    "<NSLayoutConstraint:0x60000029d330 V:|-(0)-[NSView:0x600000320dc0]   (Names: '|':NSView:0x600000320b40 )>",
    "<NSLayoutConstraint:0x60000029d060 V:[NSButton:0x6000001569a0'Search']-(4)-|   (Names: '|':NSView:0x600000320dc0 )>",
    "<NSLayoutConstraint:0x60000029d0b0 V:|-(5)-[NSButton:0x6000001569a0'Search']   (Names: '|':NSView:0x600000320dc0 )>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x60000029d060 V:[NSButton:0x6000001569a0'Search']-(4)-|   (Names: '|':NSView:0x600000320dc0 )>

2014-04-26 09:38:27.770 MyApp[2531:303] Unable to simultaneously satisfy constraints:
(
    "<NSLayoutConstraint:0x60000029dc40 V:[NSView:0x60000013fb80]-(0)-|   (Names: '|':NSView:0x60000013e500 )>",
    "<NSLayoutConstraint:0x60000029dbf0 V:[NSView:0x600000320b40]-(0)-[NSView:0x60000013fb80]>",
    "<NSLayoutConstraint:0x60000029dc90 NSView:0x60000013fb80.height >= 0.3*NSView:0x600000320b40.height>",
    "<NSAutoresizingMaskLayoutConstraint:0x608000288b60 h=--& v=--& V:[NSView:0x60000013e500(360)]>",
    "<NSLayoutConstraint:0x60000029dba0 V:|-(0)-[NSView:0x600000320b40]   (Names: '|':NSView:0x60000013e500 )>",
    "<NSLayoutConstraint:0x60000029d1a0 V:[NSView:0x600000320f00(275)]>",
    "<NSLayoutConstraint:0x60000029d420 V:[NSView:0x600000320f00]-(0)-|   (Names: '|':NSView:0x600000320b40 )>",
    "<NSLayoutConstraint:0x60000029d510 V:[NSView:0x600000320dc0]-(0)-[NSView:0x600000320f00]>",
    "<NSLayoutConstraint:0x60000029d330 V:|-(0)-[NSView:0x600000320dc0]   (Names: '|':NSView:0x600000320b40 )>",
    "<NSLayoutConstraint:0x60000029d100 V:|-(4)-[NSButton:0x6000001564d0]   (Names: '|':NSView:0x600000320dc0 )>",
    "<NSLayoutConstraint:0x60000029d150 V:[NSButton:0x6000001564d0]-(5)-|   (Names: '|':NSView:0x600000320dc0 )>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x60000029d150 V:[NSButton:0x6000001564d0]-(5)-|   (Names: '|':NSView:0x600000320dc0 )>

2014-04-26 09:38:27.775 MyApp[2531:303] Unable to simultaneously satisfy constraints:
(
    "<NSLayoutConstraint:0x60000029cf70 V:[NSTextField:0x600000198940]-(4)-|   (Names: '|':NSView:0x600000320dc0 )>",
    "<NSLayoutConstraint:0x60000029cfc0 V:|-(4)-[NSTextField:0x600000198940]   (Names: '|':NSView:0x600000320dc0 )>",
    "<NSLayoutConstraint:0x60000029dc40 V:[NSView:0x60000013fb80]-(0)-|   (Names: '|':NSView:0x60000013e500 )>",
    "<NSLayoutConstraint:0x60000029dbf0 V:[NSView:0x600000320b40]-(0)-[NSView:0x60000013fb80]>",
    "<NSLayoutConstraint:0x60000029dc90 NSView:0x60000013fb80.height >= 0.3*NSView:0x600000320b40.height>",
    "<NSAutoresizingMaskLayoutConstraint:0x608000288b60 h=--& v=--& V:[NSView:0x60000013e500(360)]>",
    "<NSLayoutConstraint:0x60000029dba0 V:|-(0)-[NSView:0x600000320b40]   (Names: '|':NSView:0x60000013e500 )>",
    "<NSLayoutConstraint:0x60000029d1a0 V:[NSView:0x600000320f00(275)]>",
    "<NSLayoutConstraint:0x60000029d420 V:[NSView:0x600000320f00]-(0)-|   (Names: '|':NSView:0x600000320b40 )>",
    "<NSLayoutConstraint:0x60000029d510 V:[NSView:0x600000320dc0]-(0)-[NSView:0x600000320f00]>",
    "<NSLayoutConstraint:0x60000029d330 V:|-(0)-[NSView:0x600000320dc0]   (Names: '|':NSView:0x600000320b40 )>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x60000029cf70 V:[NSTextField:0x600000198940]-(4)-|   (Names: '|':NSView:0x600000320dc0 )>

Answer 1

您必须“通知”父 View ，内部 View 将调整大小。我的方法是观察谓词由其委托(delegate)增长和收缩:

- (void)ruleEditorRowsDidChange:(NSNotification *)notification{

  NSInteger newRowCount = [_predicateEditor numberOfRows];
  NSInteger rowHeight = [_predicateEditor rowHeight];

  // Send a notification - size changes
  NSRect newFrame = self.view.frame;
  newFrame.size.height = 30 + newRowCount*rowHeight;
  [[NSNotificationCenter defaultCenter]postNotificationName:@"RowsDidChange" object:[NSValue valueWithRect:newFrame]];
  [[_heightConstraint animator] setConstant:rowHeight*newRowCount];
}

父 ViewController 中有一个“观察者”来观察大小变化:

 [[NSNotificationCenter defaultCenter]addObserverForName:@"RowsDidChange" 
    object:nil 
    queue:nil 
    usingBlock:^(NSNotification * notification){
        NSValue *value =  (NSValue*)notification.object;
        NSRect rectValue = [value rectValue];

        NSRect newContentRect = self.resultsView.frame;
        newContentRect.size.height = self.resultsView.frame.size.height - rectValue.size.height;
        newContentRect.size.width = self.resultsView.frame.size.width;

        // Set new height to the mainViewController
        [[self.mainViewController view] setFrame:newContentRect];
}];

您不需要发送通知，您还可以向父 View Controller 发送一些委托(delegate)方法。

祝你好运。