iphone - ZBarReaderViewController、 View Controller 层次结构和其他

Question

我正面临这个无法解决的问题，很乐意得到你的帮助。

我有一个使用 ZBar 条形码扫描仪的 iPhone 应用程序。我有一个主视图 Controller ，它在按下 UIButton 时调用 ZBar 扫描仪。一旦扫描仪启动并检测到条形码编号，它就会自动关闭，我调用结果 View Controller 来显示一些扫描结果。我的问题是关闭结果 View Controller - 由于某种原因我不能关闭它并以干净的方式返回主视图 Controller 。我的解决方法是创建一个主视图 Controller 的新对象并调用它，这是一个非常糟糕的设计。

这是我的代码 - 感谢您的帮助!

在主视图 Controller 的某处调用扫描器(UIButton 操作方法):

ZBarReaderViewController *reader = [ZBarReaderViewController new];
UINavigationController *navCntrl1 = [[UINavigationController alloc] initWithRootViewController:reader];
reader.readerDelegate = self;
reader.title = @"Scan Barcode";
reader.supportedOrientationsMask = ZBarOrientationMaskAll;
ZBarImageScanner *scanner1 = reader.scanner;
[scanner1 setSymbology: ZBAR_I25 config: ZBAR_CFG_ENABLE to: 0];
[scanner1 setSymbology: ZBAR_QRCODE config: ZBAR_CFG_ENABLE to: 0];
[self presentModalViewController:navCntrl1 animated:YES];

主 ViewController 中的 Scanner Delegate 方法:

//ZBarSDK Finish Scanning
- (void) imagePickerController: (UIImagePickerController*) reader didFinishPickingMediaWithInfo: (NSDictionary*) info
{
  id<NSFastEnumeration> results = [info objectForKey: ZBarReaderControllerResults];
ZBarSymbol *symbol = nil;
for(symbol in results)
    break;

// EXAMPLE: do something useful with the barcode data

[self dismissModalViewControllerAnimated: YES];

//Calling the Results view controller
Results *resultsViewController = [[Results alloc] initWithNibName:nil bundle:nil];
resultsViewController.tempBarcode = barcode;

UINavigationController *resultsNavigationController = [[UINavigationController alloc] initWithRootViewController:resultsViewController];
resultsNavigationController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;

[[[UIApplication sharedApplication]delegate].window setRootViewController:resultsNavigationController];

 }

这里说一下我尝试替换的地方:

[[[UIApplication sharedApplication]delegate].window setRootViewController:resultsNavigationController];

与:

[self presentModalViewController:resultsViewController animated:YES];

但如果我这样做，什么也不会发生。

在 Results ViewController 中，我这样做是为了返回到主视图 Controller :

ViewController *mainViewController = [[ViewController alloc] initWithNibName:nil bundle:nil];
UINavigationController *mainNavigationController = [[UINavigationController alloc] initWithRootViewController:mainViewController];
mainNavigationController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;    
[self presentModalViewController:mainNavigationController animated:YES];

而不仅仅是这个，这是行不通的:

[self dismissModalViewControllerAnimated:YES];

感谢您的耐心等待!

Answer 1

我有一个使用 ZBar 的类似应用程序。这是我对您的 UIButton 方法的模拟:

- (void)scanButtonTapped{
    ZBarReaderViewController *reader = [ZBarReaderViewController new];
    reader.readerDelegate = self;
    reader.supportedOrientationsMask = ZBarOrientationMaskAll;

    ZBarImageScanner *scanner = reader.scanner;

    // I need to scan only QR-codes
    [scanner setSymbology:0 config:ZBAR_CFG_ENABLE to:0];
    [scanner setSymbology:ZBAR_QRCODE config:ZBAR_CFG_ENABLE to:1];
    reader.readerView.zoom = 1.0;

    [self presentModalViewController:reader animated:YES];
    [reader release];
}

这是我的 imagePickerController:didFinishPickingMediaWithInfo:

- (void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
    id<NSFastEnumeration> results = [info objectForKey:ZBarReaderControllerResults];
    ZBarSymbol *symbol = nil;

    for (symbol in results) 
        break;

    // Here I get the QR-code text
    self.qrText = symbol.data;
    NSLog(@"QR-code text = %@",self.qrText);

    // Here I hide scanning View Controller from user
    [picker dismissModalViewControllerAnimated:YES];

    // Here I call QR-code text processing logic
    [self ticketCheckOutLogic];
}

为了调用另一个 UIViewController，我建议在 [picker dismissModalViewControllerAnimated:YES] 之后发布通知；到您的 AppDelegate，例如:

NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:self.barcodeText, @"barcodeText", nil];
[[NSNotificationCenter defaultCenter] postNotificationName:@"newBarcodeScanned" object:nil userInfo:options];

在 application:didFinishLaunchingWithOptions: 你可以这样写:

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(showResultView:)name:@"newBarcodeScanned" object:nil];

...你的 showResultView: 可以是这样的:

- (void)showResultView:(NSNotification *)notification {
     //Calling the Results view controller
     Results *resultsViewController = [[Results alloc] initWithNibName:@"ResultsView" bundle:nil];
     NSDictionary *dict = [notification userInfo];
     resultsViewController.tempBarcode = [dict objectForKey:@"barcodeText"];
     [self presentModalViewController:resultsViewController animated:YES];
}

希望对您有所帮助:)