Question

每次加载某个视图控制器时，我都会尝试打开iPhone相机。然而，它只打开一次，如果我再次加载视图控制器，它不会打开相机。每次进入视图控制器时如何打开相机？

  - (void)viewDidLoad {
[super viewDidLoad];


  UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];

if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
{
    [imagePickerController setSourceType:UIImagePickerControllerSourceTypeCamera];
}

// image picker needs a delegate,
[imagePickerController setDelegate:self];

// Place image picker on the screen
[self presentModalViewController:imagePickerController animated:YES];
}

Answer 1

在以下方法中编写上述代码

- (void)viewDidAppear:(BOOL)animated {

}

Answer 2

您可能希望使用viewDidAppear:代替viewDidLoad。

Answer 3

撰写以下代码：

- (void) viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];

    self.actionsheet = [[UIActionSheet alloc] initWithTitle:@"" delegate:self cancelButtonTitle:@"Cancel" destructiveButtonTitle:nil otherButtonTitles:@"Take Photo with Camera", @"Select from Library", nil];
    [self.actionsheet showInView:self.view];

  self.imgPicker=[[UIImagePickerController alloc] init];
  self.imgPicker.delegate=self;
  self.imgPicker.wantsFullScreenLayout = YES;
  self.imgPicker.allowsEditing=YES;

}


- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
{
    if(buttonIndex == 0)
    {
        if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
            self.imgPicker.sourceType = UIImagePickerControllerSourceTypeCamera;
        else
            self.imgPicker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
        [self presentViewController:self.imgPicker animated:YES completion:nil ];

        self.btnBlure.tag = 102;
    }
    else if (buttonIndex==1)
    {
        self.imgPicker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
        [self presentViewController:self.imgPicker animated:YES completion:nil ];

        self.btnBlure.tag = 103;
    }
}

Answer 4

如果你看viewController life cycle，你可以注意到

viewDidLoad（）仅在您第一次加载之后一次调用   当你再次切换到相同的viewController时，它不会调用   to viewDidLoad。而不是调用viewDidLoad，而是调用- (void) viewWillAppear:(BOOL)animated。
     那么你必须写你的
中的相机开启代码

- (void) viewWillAppear:(BOOL)animated方法

现在每当＆amp;你推动或呈现你的viewController多少次打开相机。

每次视图控制器处于活动状态时，我都会尝试打开相机

4 个答案: