调用viewdidload中存在的UIImagePickerControler无效

Question

I want to launch camera when my view controller loads. I tried calling takePhoto method in viewdidload but nothing happens, what did I do wrong? I am getting the following error msg: "Attempt to present on whose view is not in the window hierarchy!" When I inspect element UIImagePickerController, it is nil... Interestingly, I can place a button that calls this method and when I tap the button it works fine, but not when I call it in view did load...

- (IBAction)takePhoto {
UIImagePickerController *uiipc=[[UIImagePickerController alloc]init];
uiipc.delegate=self;
uiipc.mediaTypes=@[(NSString *)kUTTypeImage];
       uiipc.sourceType=UIImagePickerControllerSourceTypeCamera|UIImagePickerControllerSourceTypePhotoLibrary;
uiipc.allowsEditing=YES;
[self presentViewController:uiipc animated:YES completion:NULL];
 }

Answer 1

Try this: Call the camera from the view did appear method:

  //  makeCameraOff= YES;  call this in didFinishPickingMediaWithInfo method

-(void)viewDidAppear:(BOOL)animated{
  if (makeCameraOff==NO){
  [self performSelector:@selector(takePic) withObject:nil afterDelay:0];
 }
 }

-(void)takePic{

UIImagePickerController *picker = [[UIImagePickerController alloc] init];
picker.delegate =self;
picker.allowsEditing = YES;
picker.sourceType = UIImagePickerControllerSourceTypeCamera;

[self presentViewController:picker animated:YES completion:nil];


}