如何子类化NSArrayController在添加时选择文本字段： [英] How can I subclass NSArrayController to select a text field on add:

问题描述

我敢肯定，这很简单，但是我仍在学习中。

This is simple I am sure, but I am still very much learning.

我有一个NSTableView，它连接到阵列控制器以显示coredata对象。该表不可编辑。当选择单个记录时，将设置一个子视图以使其可见，该子视图包含选择的值。

I have an NSTableView that is connected to an array controller to display coredata objects. The table is uneditable. When a single record is selected, I have a subview set to be made visible that holds the value of the selection.

我正在尝试做到这一点，因此当我按下连接的+按钮添加时：在阵列控制器上，将创建一个新条目，并且焦点将跳转子视图中的项目描述文本字段，以便用户可以立即开始键入，而不必选择新的rangedObject行，然后在出现子视图时选择文本字段。

I'm trying to make it so that when I press the + button connected to add: on my array controller, a new entry will be made and the focus will jump to the item description text field in the subview so that a user could immediatily begin typing without having to select the new arrangedObject row and then the textfield when the subview appears.

有什么想法吗？

我会发布屏幕截图，但我来这里的时间还不够长。

I would post screenshots but I haven't been a user on here long enough.

推荐答案

Big Nerd Ranch的可可书（第4版）在第9章中提供了此示例。与其使用NSArrayController的-add： +按钮的方法，他们使用自定义方法创建对象，将其插入数组，处理进行中的编辑和撤消管理器分组，最后选择所需的字段进行编辑。以下是摘录：

Big Nerd Ranch's Cocoa book (4th edition) has an example of this in Chapter 9. Instead of using NSArrayController's -add: method for the + button, they use a custom method to create the object, insert it into the array, deal with in-progress edits and undo manager groupings, and finally select the desired field for editing. Here's the excerpt:

- (IBAction)createEmployee:(id)sender
{
NSWindow *w = [tableView window];
// Try to end any editing that is taking place
BOOL editingEnded = [w makeFirstResponder:w];
if (!editingEnded) {
    NSLog(@"Unable to end editing");
    return; }
NSUndoManager *undo = [self undoManager];
// Has an edit occurred already in this event?
if ([undo groupingLevel] > 0) {
    // Close the last group
    [undo endUndoGrouping];
    // Open a new group
    [undo beginUndoGrouping];
}
// Create the object
Person *p = [employeeController newObject];
// Add it to the content array of ’employeeController’
[employeeController addObject:p];
// Re-sort (in case the user has sorted a column)
[employeeController rearrangeObjects];
// Get the sorted array
NSArray *a = [employeeController arrangedObjects];
// Find the object just added
NSUInteger row = [a indexOfObjectIdenticalTo:p];
NSLog(@"starting edit of %@ in row %lu", p, row);
// Begin the edit in the first column
[tableView editColumn:0
                  row:row
            withEvent:nil
               select:YES];
}

完整实现位于 https://github.com/preble/Cocoa4eSolutions 。

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