我有一个使用NSOpenPanel的应用程序，因此用户可以选择多个文件进行导入，并且还具有典型的首选项面板。首选项面板存储在.xib文件中。
用户调出首选项面板后发生问题。在此之前，NSOpenPanel绝对可以正常工作，所有逻辑都在完成块中执行，可以一次又一次地调用它。但是，一旦用户出售“首选项”选项并关闭该工作表，则随后每次对-(IBAction)addFiles:的调用都会导致异常：
它们的声明如下：
@interface BQSAppDelegate
{
NSOpenPanel *addFilesPanel;
}
@property(assign)IBOutlet NSPanel*prefs_panel; //connected to a NSPanel in the .xib
并用于：
@implementation BQSAppDelegate
-(void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
// other initialisations not to do with addFilesPanel….
addFilesPanel = [NSOpenPanel openPanel];
addFilesPanel.canChooseDirectories = YES;
addFilesPanel.allowsMultipleSelection = YES;
}
-(IBAction)addFiles:(id)sender //button on main window pressed
{
[addFilesPanel beginSheetModalForWindow:self.window completionHandler:^(NSInteger result) {
if (addFilesPanel.URLs.count < 1 || result != NSFileHandlingPanelOKButton) {
NSLog(@“User cancelled”);
[addFilesPanel orderOut:self]; //I’ve tried it without this line with exactly the same results
}
else {
//do things…
}
}];
}
-(IBAction)preferences:(id)sender //bound to the usual Apple+’,” shortcut and app menu item
{
if (self.prefs_panel.isVisible) {
return;
}
[self.window beginSheet:self.prefs_panel completionHandler:^(NSModalResponse returnCode) {
NSLog(@"completed"); //is never executed...
}];
}
-(IBAction)ok_prefs:(id)sender //called when the user presses a button on the Preference panel
{
[self.prefs_panel orderOut:self];
}
例外是：
2015-03-18 20:35:29.913 QS[3634:241869] *** Assertion failure in void associateSheetWithHost(NSWindow *, NSWindow *)(), /SourceCache/ViewBridge/ViewBridge-103/ViewBridgeUtilities.m:83
2015-03-18 20:35:29.914 QS[3634:241869] sheet <NSVBOpenPanel: 0x1003504f0> already has a host <NSWindow: 0x6000001e5e00>
2015-03-18 20:35:29.917 QS[3634:241869] (
0 CoreFoundation 0x00007fff95e7366c __exceptionPreprocess + 172
1 libobjc.A.dylib 0x00007fff8db6776e objc_exception_throw + 43
2 CoreFoundation 0x00007fff95e7344a +[NSException raise:format:arguments:] + 106
3 Foundation 0x00007fff9399e471 -[NSAssertionHandler handleFailureInFunction:file:lineNumber:description:] + 169
4 ViewBridge 0x00007fff8c931333 -[NSWindow(ViewBridgeNeedsSPI) _setSheetHost:] + 305
5 AppKit 0x00007fff8b367a2f -[NSVBSavePanel beginSheetModalForWindow:completionHandler:] + 69
6 QS 0x0000000100017684 -[BQSAppDelegate addFolders:] + 212
7 libsystem_trace.dylib 0x00007fff8be72cd7 _os_activity_initiate + 75
8 AppKit 0x00007fff8acd8b71 -[NSApplication sendAction:to:from:] + 452
9 AppKit 0x00007fff8acd8970 -[NSControl sendAction:to:] + 86
10 AppKit 0x00007fff8aeae86c __26-[NSCell _sendActionFrom:]_block_invoke + 131
11 libsystem_trace.dylib 0x00007fff8be72cd7 _os_activity_initiate + 75
12 AppKit 0x00007fff8ad21509 -[NSCell _sendActionFrom:] + 144
13 libsystem_trace.dylib 0x00007fff8be72cd7 _os_activity_initiate + 75
14 AppKit 0x00007fff8ad3c085 -[NSCell trackMouse:inRect:ofView:untilMouseUp:] + 2775
15 AppKit 0x00007fff8ad3b2b9 -[NSButtonCell trackMouse:inRect:ofView:untilMouseUp:] + 491
16 AppKit 0x00007fff8ad3a899 -[NSControl mouseDown:] + 714
17 AppKit 0x00007fff8b238a18 -[NSWindow _reallySendEvent:] + 12721
18 AppKit 0x00007fff8acbf16e -[NSWindow sendEvent:] + 446
19 AppKit 0x00007fff8ac71451 -[NSApplication sendEvent:] + 4183
20 AppKit 0x00007fff8aafd608 -[NSApplication run] + 711
21 AppKit 0x00007fff8aae8a14 NSApplicationMain + 1832
22 QS 0x0000000100001fe2 main + 34
23 libdyld.dylib 0x00007fff90d485c9 start + 1
这一定与我打电话和/或解雇NSPanel的方式有关，但我不知道该怎么办。非常感谢您的帮助。
最佳答案
这是一条隐秘的错误消息，尽管评论解决了问题，但我不确定我是否理解它的措辞。我当时认为这与与工作表相关的模式运行循环有关，并且可能与此有关—也许，模式化会话的所有开销仍然在周围活跃起来，除非您调用endSheet 。
提示来自this related question about the completion handler not being invoked.那里的第二个未接受的答案似乎表明您必须杀死模式会话，而不仅仅是杀死工作表。
关于macos - NSPanel导致随后使用NSOpenPanel生成异常，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/29133529/