首次点击时按钮动作不完美？

Question

我有一个应用程序，我的xib中有一个UIView（Zbarsdk阅读器视图）。点击按钮时，应加载该视图。但实际上当点击按钮时，先前的视图正在加载（我从中看到了我的视图）。但在运行一次然后再次运行然后加载正确的视图？ （从登录我来到家。在家里我有一个按钮来加载一个在我的xib中独立的视图，但是当它首先运行时它再次加载登录屏幕。但是当你再次在模拟器中运行该代码时不删除该构建正在加载正确的视图）。有人知道为什么吗？

- (IBAction) tappressed
{
    // ADD: present a barcode reader that scans from the camera feed
    ZBarReaderViewController *reader = [ZBarReaderViewController new];
    reader.readerDelegate = self;
    [reader willRotateToInterfaceOrientation:UIInterfaceOrientationPortrait duration:0];
    //[self.readerView willRotateToInterfaceOrientation:orient duration:0];
    //reader.supportedOrientationsMask = ZBarOrientationMask(UIInterfaceOrientationLandscapeRight);

    // [reader shouldAutorotateToInterfaceOrientation:UIInterfaceOrientationLandscapeRight];
    //reader.supportedOrientationsMask = ZBarOrientationMask(UIInterfaceOrientationLandscapeLeft);
    reader.sourceType=UIImagePickerControllerSourceTypeCamera;
    // UIImageView *overlayImage=[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"overlaygraphic.png"]];
    //overlayImage.bounds=CGRectMake(50, 75, 320-100, 480-150);

    reader.cameraOverlayView=cameraOverlay;
    ZBarImageScanner *scanner = reader.scanner;
    // TODO: (optional) additional reader configuration here

    // EXAMPLE: disable rarely used I2/5 to improve performance

    [scanner setSymbology: ZBAR_I25
             config: ZBAR_CFG_ENABLE
             to: 0];

    // present and release the controller
    [self presentModalViewController:reader animated:YES];

    // [self.view addSubview:reader.view];
    [reader release];
}