Question

我今天看到了一种奇怪的行为。我试图从一个名为“BloodWingViewController（viewcontroller的子类）”的viewcontroler中打开uiimagepickercontroller。以下是显示选择器的代码：

if (self.picker == nil) {   

    [SVProgressHUD showWithStatus:@"Loading picker..."];

    dispatch_queue_t concurrentQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    dispatch_async(concurrentQueue, ^{

        self.picker = [[[UIImagePickerController alloc] init] autorelease];
        self.picker.delegate = self;
        self.picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
        self.picker.allowsEditing = NO;    

        dispatch_async(dispatch_get_main_queue(), ^{
            [self.navigationController presentModalViewController:picker animated:YES];    
            [SVProgressHUD dismiss];
        });

    });        

}  else {        
    [self.navigationController presentModalViewController:picker animated:YES];    
}

以上代码工作绝对正常，没问题。我看到的奇怪的事情是，如果我通过push seague进入这个所谓的“BllodWingViewController”并尝试打开选择器然后它的工作原理。但是，如果我通过模态塞格再次进入所谓的“BllodWingViewController”并尝试打开选择器，那么它根本不起作用。没有选择器打开。你可以解释一下这背后的原因吗？以及如何克服这个问题，因为我必须从通过模态接口连接执行的viewcontroller打开选择器。

如果它让你感到困惑，抱歉我的英语：P

编辑：

- (IBAction)onPhotoPickerClick:(id)sender {
if (self.picker == nil) {   

    [SVProgressHUD showWithStatus:@"Loading picker..."];

    dispatch_queue_t concurrentQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    dispatch_async(concurrentQueue, ^{

        self.picker = [[[UIImagePickerController alloc] init] autorelease];
        self.picker.delegate = self;
        self.picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
        self.picker.allowsEditing = NO;         

        dispatch_async(dispatch_get_main_queue(), ^{
            [self.navigationController presentModalViewController:picker animated:YES];    
            [SVProgressHUD dismiss];
        });

    });        

}  else {        
    [self.navigationController presentModalViewController:picker animated:YES];    
}

}

#import <UIKit/UIKit.h>

@interface EditStudentViewController：UIViewController { UIImagePickerController * picker; }

（IBAction为）onPhotoPickerClick：（ID）发送者;

@property（retain，nonatomic）UIImagePickerController * picker;

@end

现在，当我使用推送segue连接来到EditStudentViewController时，onPhotoPickerClick正在工作，意味着photolibary显示，我可以选择图像。但是当我从之前的viewcontroller来到EditStudentViewController时，photolibary根本就没有显示出来。

感谢。

UIImagePickerController：Modal和Push Segue

0 个答案: