小编Diw*_*ann的帖子

当您实际滚动到下一页时,我试图重现滚动视图的平滑动画,并启用分页.它似乎是UIViewAnimationCurveEaseInOut,但我需要一个"下一页"按钮并以编程方式触发滚动.

这是我的代码:

-(void) scrollToPage:(int)page
{
    UIScrollView *scrollView = contentView;
    CGPoint offset = CGPointMake(scrollView.bounds.size.width * page, scrollView.contentOffset.y);
    [scrollView setContentOffset:offset animated: YES];     
    [self pageControlUpdate];
}

-(void) scrollToNextPage 
{
    [self scrollToPage:(pageControl.currentPage + 1)];
}

我无法重现平滑UIViewAnimationCurveEaseInOut,无论是用setContentOffset还是用scrollRectToVisible......它都会带着丑陋的线性动画进入下一页

我甚至尝试手动设置动画:

[UIView animateWithDuration:.5 delay:0 options:UIViewAnimationCurveEaseInOut animations:^{
    scrollView.contentOffset = offset;
} completion:^(BOOL finished) {    } ];

我哪里错了？

我有一个随机的问题,当我提出UIImagePickerController捕捉照片.有时预览屏幕只是黑色.(这可能是第一次,可能是第二次,或者可以永远,甚至永远不会).然而,我可以看到相机控制,黄色方块可以进行人脸检测.如果我等待一段时间(约20秒),黑色预览消​​失,预览出现......

以下是我有时可以在日志中看到的内容:

快照未呈现的视图会导致空快照.确保在屏幕更新后快照或快照之前至少渲染了一次视图.

config:xcode 5.1.1,iPhone 5/5S,ios 7.0/7.1

这是一个为我重现问题的代码:

-(void) showCamera
{ 
    UIImagePickerController *pickerController = [[UIImagePickerController alloc] init];
    pickerController.allowsEditing = NO;
    pickerController.sourceType     = UIImagePickerControllerSourceTypeCamera;
    pickerController.cameraDevice   = UIImagePickerControllerCameraDeviceFront;
    pickerController.cameraOverlayView = nil;

    UIViewController *topController = [UIApplication sharedApplication].keyWindow.rootViewController;
    while (topController.presentedViewController) {
        topController = topController.presentedViewController;
    }

    [topController presentViewController:pickerController animated:YES completion:nil];
}

当然,对于我的真实应用程序,我测试是否有相机:

[UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]);

我发现了几个类似的问题,但没有任何真正的答案:

• UIImagePickerController显示黑色预览屏幕

• iOS 7 UIImagePicker预览黑屏

我已经尝试了他们的建议,没有成功.

编辑:这里有一些代码:正如所说的,我创建了一个单例类,子类化UIImagePickerController:

@implementation BBImagePickerController

static BBImagePickerController *sharedInstance = nil;

+ (BBImagePickerController *) sharedInstance
{
    if (!sharedInstance)
        sharedInstance = [[BBImagePickerController alloc] init];

    return sharedInstance;
} …