ios - 如何防止像 iPhone 照片应用程序那样自动旋转？

Question

我想阻止 UICollectionViewController 在屏幕上有手指时自动旋转。手指可以移动，设备可以旋转，但只要手指仍在屏幕上，UICollectionViewController 就不应旋转。

当手指离开屏幕时，UICollectionViewController 应该立即旋转。正如 iPhone 照片应用程序所做的那样。

问题:

1. 如何检测触摸？

   我覆盖了 UICollectionView 子类中的 touchBegan:withEvent: 等。但是当 UICollectionView 开始滚动时，它会调用 touchCanceled:withEvent: 方法。

   如果我更早开始滚动 UICollectionView，touchBegan:withEvent: 甚至不会触发。

2. 如何暂时防止自动旋转？

   我覆盖了我的 View Controller 中的 shouldAutorotate 以防止旋转。但是当手指离开屏幕时，UICollectionView 不能立即旋转。

Answer 1

请试试这段代码:

@interface BlockAutorotateViewController ()

@property (nonatomic, strong) UILongPressGestureRecognizer *longPressGestureRecognizer;
@property (nonatomic, strong) UISwipeGestureRecognizer *swipeGestureRecognizer;
@property (nonatomic, assign, getter = isPressed) BOOL pressed;

@end

@implementation BlockAutorotateViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.pressed = NO;

    self.longPressGestureRecognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(myLongPressAction:)];
    self.longPressGestureRecognizer.minimumPressDuration = 0;
    [self.view addGestureRecognizer:self.longPressGestureRecognizer];

    self.swipeGestureRecognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(mySwipeAction:)];
    [self.view addGestureRecognizer:self.swipeGestureRecognizer];

}

- (void)myLongPressAction:(id)sender
{
    if ((self.longPressGestureRecognizer.state == UIGestureRecognizerStateEnded) || (self.longPressGestureRecognizer.state == UIGestureRecognizerStateChanged))  {
        self.pressed = YES;
    }
    else if (self.longPressGestureRecognizer.state == UIGestureRecognizerStateBegan) {
        self.pressed = NO;
        [UIViewController attemptRotationToDeviceOrientation];
    }
    else {
        self.pressed = NO;
    }
}

- (void)mySwipeAction:(id)sender
{
    if ((self.swipeGestureRecognizer.state == UIGestureRecognizerStateBegan) || (self.longPressGestureRecognizer.state == UIGestureRecognizerStateChanged))  {
        self.pressed = YES;
    }
    else if (self.longPressGestureRecognizer.state == UIGestureRecognizerStateEnded) {
        self.pressed = NO;
        [UIViewController attemptRotationToDeviceOrientation];
    }
    else {
        self.pressed = NO;
    }
}

- (BOOL)shouldAutorotate
{
    return (self.isPressed ? NO : YES);
}

@end