iphone - indexPathForRowAtPoint 不会给我正确的索引

Question

我正在尝试实现一个类似 twitter iPhone 应用程序的界面。 (滑动即可用自定义 View 替换 tableviewcell 中的 View )。我使用 Apple 的 UISwipeGestureRecognizer 来识别滑动，并使用 [recognizer locationInView:self.view] 获取该滑动的起始位置。这给了我一个 CGPoint，我将其与 [tableView indexPathForRowAtPoint:location] 一起使用。我的问题是，我的滑动似乎总是在我滑动的实际行上方或下方的一行被检测到。有人遇到过同样的问题吗？

编辑:我可能还应该提到我正在使用自定义表格 View 单元格，并且它的高度大于默认 View 。我不确定这是否有任何区别，我使用 heightForRowIndexAtPath: 返回高度。

我的代码是 -

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
ModelObject *rowData = (ModelObject *)[tempArr objectAtIndex:indexPath.row];
if (rowData.isAlternateView) {
        // Load alternateview
    UISwipeGestureRecognizer *recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipe:)];
    [recognizer setDirection:(UISwipeGestureRecognizerDirectionRight)];
    [cell addGestureRecognizer:recognizer];
    [recognizer release]; 
    return cell;

}
else {
    // Load the correct uitableviewcell
    UISwipeGestureRecognizer *recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipe:)];
    [recognizer setDirection:(UISwipeGestureRecognizerDirectionRight)];
    [cell addGestureRecognizer:recognizer];
    [recognizer release]; 

    return cell;
}

}


-(void) handleSwipe:(UISwipeGestureRecognizer *) recognizer
{
NSLog(@"Swipe detected!");
CGPoint location = [recognizer locationInView:self.view];   
NSIndexPath *selectedIndexPath = [tableView indexPathForRowAtPoint:location];
NSLog(@"Swipe detected at %d", selectedIndexPath.row);
ModelObject *rowData = (ModelObject *)[modelArr objectAtIndex:selectedIndexPath.row];
rowData.isAlternateView = YES;

for (int i=0; i<[tempArr count]; i++) {
    if (i!=selectedIndexPath.row) {
        ModelObject *rowToBeCleared = (ModelObject *) [modelArr objectAtIndex:i];
        if ([rowToBeCleared isAlternateView]) {
            [rowToBeCleared setIsAlternateView:NO];
            [tableView reloadRowsAtIndexPaths:[NSArray arrayWithObjects:[NSIndexPath indexPathForRow:i inSection:0],nil] withRowAnimation:UITableViewRowAnimationLeft];
        }
    }
}

[tableView reloadRowsAtIndexPaths:[NSArray arrayWithObjects:selectedIndexPath,nil] withRowAnimation:UITableViewRowAnimationRight];
}

Answer 1

首先，我建议不要向每个单元格添加手势识别器，而是建议仅向包含表格 View 的整个 View 添加一个手势识别器(或者如果这是一个 UITableViewController，那么它们是同一件事)。

在viewDidLoad中:

UISwipeGestureRecognizer *recognizer = [[UISwipeGestureRecognizer alloc] 
    initWithTarget:self action:@selector(handleSwipe:)];
[recognizer setDirection:(UISwipeGestureRecognizerDirectionRight)];
[self.view addGestureRecognizer:recognizer];
[recognizer release];

然后，在handleSwipe方法中:

- (void)handleSwipe:(UISwipeGestureRecognizer *) recognizer
{
    //might need to check if swipe has ended (otherwise not time to handle yet)
    if (recognizer.state != UIGestureRecognizerStateEnded)
        return;

    CGPoint location = [recognizer locationInView:tableView]; //not self.view  
    NSIndexPath *selectedIndexPath = [tableView indexPathForRowAtPoint:location];

    if (selectedIndexPath != nil)
    {
        //user swiped on a tableview cell
    }
    else
    {
        //user did not swipe on a tableview cell
    }
}