等待[NSAlert beginSheetModalForWindow:...];

时间:2009-03-03 01:22:57

标签: cocoa macos alerts document-based

当我显示这样的NSAlert时,我立刻得到了答案:

int response;
NSAlert *alert = [NSAlert alertWithMessageText:... ...];
response = [alert runModal];

问题是这是应用程序模式,我的应用程序是基于文档的。我使用工作表在当前文档的窗口中显示警报,如下所示:

int response;
NSAlert *alert = [NSAlert alertWithMessageText:... ...];
[alert beginSheetModalForWindow:aWindow
                  modalDelegate:self
                 didEndSelector:@selector(alertDidEnd:returnCode:contextInfo:)
                    contextInfo:&response];

//elsewhere
- (void) alertDidEnd:(NSAlert *) alert returnCode:(int) returnCode contextInfo:(int *) contextInfo
{
    *contextInfo = returnCode;
}

唯一的问题是beginSheetModalForWindow:会立即返回,因此我无法可靠地向用户询问问题并等待回复。如果我可以将任务分成两个区域,那么这不会是一件大事,但我不能。

我有一个处理大约40个不同对象(在树中)的循环。如果一个对象失败,我希望警报显示并询问用户是继续还是中止(继续在当前分支处理),但由于我的应用程序是基于文档的,因此Apple人机界面指南要求在警报为时使用工作表特定于文件。

如何显示警报表并等待回复?

12 个答案:

答案 0 :(得分:14)

我们创建了一个category on NSAlert to run alerts synchronously,就像应用程序模式对话框一样:

NSInteger result;

// Run the alert as a sheet on the main window
result = [alert runModalSheet];

// Run the alert as a sheet on some other window
result = [alert runModalSheetForWindow:window];

代码可以通过GitHub获得,并且下面发布了当前版本的完整性。


标题文件NSAlert+SynchronousSheet.h

#import <Cocoa/Cocoa.h>


@interface NSAlert (SynchronousSheet)

-(NSInteger) runModalSheetForWindow:(NSWindow *)aWindow;
-(NSInteger) runModalSheet;

@end

实施文件NSAlert+SynchronousSheet.m

#import "NSAlert+SynchronousSheet.h"


// Private methods -- use prefixes to avoid collisions with Apple's methods
@interface NSAlert ()
-(IBAction) BE_stopSynchronousSheet:(id)sender;   // hide sheet & stop modal
-(void) BE_beginSheetModalForWindow:(NSWindow *)aWindow;
@end


@implementation NSAlert (SynchronousSheet)

-(NSInteger) runModalSheetForWindow:(NSWindow *)aWindow {
    // Set ourselves as the target for button clicks
    for (NSButton *button in [self buttons]) {
        [button setTarget:self];
        [button setAction:@selector(BE_stopSynchronousSheet:)];
    }

    // Bring up the sheet and wait until stopSynchronousSheet is triggered by a button click
    [self performSelectorOnMainThread:@selector(BE_beginSheetModalForWindow:) withObject:aWindow waitUntilDone:YES];
    NSInteger modalCode = [NSApp runModalForWindow:[self window]];

    // This is called only after stopSynchronousSheet is called (that is,
    // one of the buttons is clicked)
    [NSApp performSelectorOnMainThread:@selector(endSheet:) withObject:[self window] waitUntilDone:YES];

    // Remove the sheet from the screen
    [[self window] performSelectorOnMainThread:@selector(orderOut:) withObject:self waitUntilDone:YES];

    return modalCode;
}

-(NSInteger) runModalSheet {
    return [self runModalSheetForWindow:[NSApp mainWindow]];
}


#pragma mark Private methods

-(IBAction) BE_stopSynchronousSheet:(id)sender {
    // See which of the buttons was clicked
    NSUInteger clickedButtonIndex = [[self buttons] indexOfObject:sender];

    // Be consistent with Apple's documentation (see NSAlert's addButtonWithTitle) so that
    // the fourth button is numbered NSAlertThirdButtonReturn + 1, and so on
    NSInteger modalCode = 0;
    if (clickedButtonIndex == NSAlertFirstButtonReturn)
        modalCode = NSAlertFirstButtonReturn;
    else if (clickedButtonIndex == NSAlertSecondButtonReturn)
        modalCode = NSAlertSecondButtonReturn;
    else if (clickedButtonIndex == NSAlertThirdButtonReturn)
        modalCode = NSAlertThirdButtonReturn;
    else
        modalCode = NSAlertThirdButtonReturn + (clickedButtonIndex - 2);

    [NSApp stopModalWithCode:modalCode];
}

-(void) BE_beginSheetModalForWindow:(NSWindow *)aWindow {
    [self beginSheetModalForWindow:aWindow modalDelegate:nil didEndSelector:nil contextInfo:nil];
}

@end

答案 1 :(得分:7)

解决方案是致电

[NSApp runModalForWindow:alert];
在beginSheetModalForWindow之后

。此外,您需要实现捕获“对话框已关闭”操作的委托,并在响应中调用[NSApp stopModal]。

答案 2 :(得分:6)

这是一个解决问题的NSAlert类别(正如Philipp所建议的解决方案由Frederick提出并由Laurent P改进:我使用代码块代替委托,因此再次简化)。

@implementation NSAlert (Cat)

-(NSInteger) runModalSheetForWindow:(NSWindow *)aWindow
{
    [self beginSheetModalForWindow:aWindow completionHandler:^(NSModalResponse returnCode)
        { [NSApp stopModalWithCode:returnCode]; } ];
    NSInteger modalCode = [NSApp runModalForWindow:[self window]];
    return modalCode;
}

-(NSInteger) runModalSheet {
    return [self runModalSheetForWindow:[NSApp mainWindow]];
}

@end

答案 3 :(得分:5)

万一有人来找这个(我做过),我用以下方法解决了这个问题:

@interface AlertSync: NSObject {
    NSInteger returnCode;
}

- (id) initWithAlert: (NSAlert*) alert asSheetForWindow: (NSWindow*) window;
- (NSInteger) run;

@end

@implementation AlertSync
- (id) initWithAlert: (NSAlert*) alert asSheetForWindow: (NSWindow*) window {
    self = [super init];

    [alert beginSheetModalForWindow: window
           modalDelegate: self didEndSelector: @selector(alertDidEnd:returnCode:) contextInfo: NULL];

    return self;
}

- (NSInteger) run {
    [[NSApplication sharedApplication] run];
    return returnCode;
}

- (void) alertDidEnd: (NSAlert*) alert returnCode: (NSInteger) aReturnCode {
    returnCode = aReturnCode;
    [[NSApplication sharedApplication] stopModal];
}
@end

然后同步运行NSAlert就像:

AlertSync* sync = [[AlertSync alloc] initWithAlert: alert asSheetForWindow: window];
int returnCode = [sync run];
[sync release];

请注意,如所讨论的那样存在重新引发问题的可能性,因此如果这样做,请小心。

答案 4 :(得分:3)

不幸的是,你在这里做的并不多。您基本上必须做出决定:重新构建您的应用程序,以便它可以以异步方式处理对象,或者使用未经批准,弃用的呈现应用程序模态警报的体系结构。

在不知道有关您的实际设计以及如何处理这些对象的任何信息的情况下,很难提供任何进一步的信息。然而,在我的头脑中,可能会有几个想法:

  • 处理另一个线程中的对象,该线程通过某种运行循环信号或队列与主线程通信。如果窗口的对象树被中断,它会向主线程发出信号,表明它已被中断,并等待来自主线程的信号,其中包含有关做什么的信息(继续此分支或中止)。然后主线程呈现文档模态窗口,并在用户选择要执行的操作后发出进程线程的信号。

然而,这可能真的过于复杂了。在这种情况下,我的建议是仅使用已弃用的用法,但这实际上取决于您的用户要求。

答案 5 :(得分:1)

这是我的回答:

创建一个全局类变量'NSInteger alertReturnStatus'

- (void)alertDidEndSheet:(NSWindow *)sheet returnCode:(NSInteger)returnCode contextInfo:(void *)contextInfo
{
    [[sheet window] orderOut:self];
    // make the returnCode publicly available after closing the sheet
    alertReturnStatus = returnCode;
}


- (BOOL)testSomething
{

    if(2 != 3) {

        // Init the return value
        alertReturnStatus = -1;

        NSAlert *alert = [[[NSAlert alloc] init] autorelease];
        [alert addButtonWithTitle:@"OK"];
        [alert addButtonWithTitle:@"Cancel"];
        [alert setMessageText:NSLocalizedString(@"Warning", @"warning")];
        [alert setInformativeText:@"Press OK for OK"];
        [alert setAlertStyle:NSWarningAlertStyle];
        [alert setShowsHelp:NO];
        [alert setShowsSuppressionButton:NO];

        [alert beginSheetModalForWindow:[self window] modalDelegate:self didEndSelector:@selector(alertDidEndSheet:returnCode:contextInfo:) contextInfo:nil];

        // wait for the sheet
        NSModalSession session = [NSApp beginModalSessionForWindow:[alert window]];
        for (;;) {
            // alertReturnStatus will be set in alertDidEndSheet:returnCode:contextInfo:
            if(alertReturnStatus != -1)
                break;

            // Execute code on DefaultRunLoop
            [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode 
                                     beforeDate:[NSDate distantFuture]];

            // Break the run loop if sheet was closed
            if ([NSApp runModalSession:session] != NSRunContinuesResponse 
                || ![[alert window] isVisible]) 
                break;

            // Execute code on DefaultRunLoop
            [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode 
                                     beforeDate:[NSDate distantFuture]];

        }
        [NSApp endModalSession:session];
        [NSApp endSheet:[alert window]];

        // Check the returnCode by using the global variable alertReturnStatus
        if(alertReturnStatus == NSAlertFirstButtonReturn) {
            return YES;
        }

        return NO;
    }
    return YES;
}

希望它会有所帮助, 干杯 --Hans

答案 6 :(得分:1)

这是上面Laurent等人的版本,为Xcode 6.4(截至今天的最新工作版本)翻译成Swift 1.2并在我的应用程序中进行了测试。感谢所有为此工作做出贡献的人! Apple的标准文档没有提供关于如何处理这个问题的线索,至少在任何我找不到的地方都没有。

我仍然有一个谜:为什么我必须在最后一个函数中使用双感叹号。 NSApplication.mainWindow应该只是一个可选的NSWindow(NSWindow?),对吧?但是编译器给出了错误,直到我使用了第二个'!'。

extension NSAlert {
    func runModalSheetForWindow( aWindow: NSWindow ) -> Int {
        self.beginSheetModalForWindow(aWindow) { returnCode in
            NSApp.stopModalWithCode(returnCode)
        }
        let modalCode = NSApp.runModalForWindow(self.window as! NSWindow)
        return modalCode
    }

    func runModalSheet() -> Int {
        // Swift 1.2 gives the following error if only using one '!' below:
        // Value of optional type 'NSWindow?' not unwrapped; did you mean to use '!' or '?'?
        return runModalSheetForWindow(NSApp.mainWindow!!)
    }
}

答案 7 :(得分:1)

迅速5:

extension NSAlert {

  /// Runs this alert as a sheet.
  /// - Parameter sheetWindow: Parent window for the sheet.
  func runSheetModal(for sheetWindow: NSWindow) -> NSApplication.ModalResponse {
    beginSheetModal(for: sheetWindow, completionHandler: NSApp.stopModal(withCode:))
    return NSApp.runModal(for: sheetWindow)
  }
}

答案 8 :(得分:0)

与Windows不同,我认为没有办法阻止模态对话框。输入(例如用户点击按钮)将在主线程上处理,因此无法阻止。

对于您的任务,您必须将消息传递到堆栈中,然后从中断处继续。

答案 9 :(得分:0)

当一个对象失败时,停止处理树中的对象,记下哪个对象失败(假设有一个订单,你可以从你离开的地方拿起),并抛出工作表。当用户取消工作表时,让didEndSelector:方法从它停止使用的对象再次开始处理,具体取决于returnCode

答案 10 :(得分:0)

- (bool) windowShouldClose: (id) sender
 {// printf("windowShouldClose..........\n");
  NSAlert *alert=[[NSAlert alloc ]init];
  [alert setMessageText:@"save file before closing?"];
  [alert setInformativeText:@"voorkom verlies van laatste wijzigingen"];
  [alert addButtonWithTitle:@"save"];
  [alert addButtonWithTitle:@"Quit"];
  [alert addButtonWithTitle:@"cancel"];
  [alert beginSheetModalForWindow: _window modalDelegate: self
              didEndSelector: @selector(alertDidEnd: returnCode: contextInfo:)
                 contextInfo: nil];
  return false;
}

答案 11 :(得分:0)

您可以使用dispatch_group_wait(group, DISPATCH_TIME_FOREVER);

dispatch_group_t group = dispatch_group_create();
dispatch_group_enter(group);

NSAlert *alert = [[NSAlert alloc] init];
[alert setMessageText:@"alertMessage"];
[alert addButtonWithTitle:@"Cancel"];
[alert addButtonWithTitle:@"Ok"];

dispatch_async(dispatch_get_main_queue(), ^{
    [alert beginSheetModalForWindow:progressController.window completionHandler:^(NSModalResponse returnCode) {
         if (returnCode == NSAlertSecondButtonReturn) {
             // do something when the user clicks Ok

         } else {
             // do something when the user clicks Cancel
         }

         dispatch_group_leave(group);
     }];
});

dispatch_group_wait(group, DISPATCH_TIME_FOREVER);

//you can continue your code here

希望有帮助。