Question

我在桌面视图上放置了一个`UIPanGestureRecognizer：

UIPanGestureRecognizer *swipe = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(closeCell:)];
swipe.minimumNumberOfTouches = 1;
swipe.maximumNumberOfTouches = 1;
swipe.delegate = self;
[self.tableView addGestureRecognizer:swipe];

我正在尝试将初始触摸y坐标设置为initialY var。我尝试通过在swipe.state等于UIGestureRecognizerStateBegan时设置它来执行此操作。这样做的目的是在UIGestureRecognizerStateChanged时使用它，但在此方法中，initalY设置为1。这是为什么？

    -(void)closeCell:(UIPanGestureRecognizer *)swipe {

        CGPoint pointInView = [swipe locationInView:swipe.view];
        NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:pointInView];
        UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];


        int initalY;
        int changeInMovement = 0;

        if (indexPath == expandIndexPath) {

            [self.tableView setScrollEnabled:NO];

            if (swipe.state == UIGestureRecognizerStateBegan) {
                CGPoint pointInCell = [swipe locationInView:cell];
                initalY = pointInCell.y;

                NSLog(@"BEGAN");
                NSLog(@"INITIAL Y: %d", initalY);

            }

            if (swipe.state == UIGestureRecognizerStateChanged) {
                CGPoint pointInCell = [swipe locationInView:cell];
                int currentY = pointInCell.y;
                changeInMovement = initalY - currentY;
                NSLog(@"initial Y: %d", initalY);
                NSLog(@"current Y: %d", currentY);
                NSLog(@"change in Y: %d", changeInMovement);

                //THE PROBLEM IS THAT INITAL Y BECOMES 1

            }
        }
}

Answer 1

因为它是一个局部变量。它将被创建＆＃34;每次调用该方法时都是新鲜的。

您可以将变量设为静态，这将保留其值。静态变量在实例（例如，具有相同类的所有viewControllers）之间以及方法调用之间共享。只需添加关键字static：

即可

static int initalY = 0;
static int changeInMovement = 0;

为什么我的int变量在我设置后会发生变化？

1 个答案: