cocoa - 不 initWithWindowNibName 设置窗口字段

Question

我正在尝试使用以下代码来工作。它第一次执行预期的操作，打开一个窗口并将其设为前窗口，但是当随后调用它时， orderFront: 不起作用，因为 window 为 nil。为什么 initWithWindowNibName: 不设置从 initWithNibName: 返回的 NSWindowController 对象的窗口字段？

//
//  CustomerCard.m
//  POSWonder
//
//  Created by kaydell on 2/26/12.
//  Copyright 2012 Kaydell Leavitt. All rights reserved.
//

#import "CustomerCard.h"

@implementation CustomerCard

// declare customerCard as a static variable
static CustomerCard* customerCard;

+(void) show {

    // if the customer card isn't instantiated, then instantiate it
    if (customerCard == nil) {
        customerCard = [[CustomerCard alloc] initWithWindowNibName:@"CustomerCard"];
        if (!customerCard.window) {
            NSLog(@"Why is window nil here?"); // <<<<<<<<<<< This line gets called <<<<<
        }
    }

    // show the customer card and make it the front window
    [customerCard showWindow:self];
    [customerCard.window orderFront:self]; // <<<<<<<< This line doesn't seem to do anything

}

-(void) dealloc {
    customerCard = nil;
    [super dealloc];
}

@end

Answer 1

在 Interface Builder 中，您需要取消选中标有“关闭时释放”的框。如果启用此复选框，窗口将被释放，并可能在关闭时被释放。

如果您想保留窗口，您不希望出现这种行为，因此您需要将其关闭。