ios - 当用户使用长按手势时如何在 Collection View 单元格中显示按钮。

Question

好吧，过去两天我一直很震惊，但还没有找到任何解决方案。我正在处理集合，我在每个集合单元格上动态创建一个按钮并将其隐藏，当用户使用长按手势时，按钮应该显示在每个单元格中。我应该如何实现这一点。任何想法都非常感谢。

-  (void)handleLongPress:(UILongPressGestureRecognizer*)gestureRecognizer

{

    if (gestureRecognizer.state == UIGestureRecognizerStateEnded)

    {
        userButtonOutlet.hidden=YES;
        saveButtonOutlet.hidden=NO;
        secondsLeft = minutes = seconds = 0;
        if (timerr) {
            [timerr invalidate];
        }
        timerr = [NSTimer scheduledTimerWithTimeInterval:1.0f target:self selector:@selector(updateCounter:) userInfo:nil repeats:YES];

        secondsLeft=1800;
        cancelSessionButtonOutlet.hidden=NO;
      //  [collectionData reloadData];
        //Do Whatever You want on End of Gesture
    }
    else if(gestureRecognizer.state == UIGestureRecognizerStateBegan)
    {
       NSLog(@"UIGestureRecognizerStateStarted");
    }
}

- (IBAction)cancelSessionButton:(id)sender
{

    NSLog(@"TEST");
    cancelSessionButtonOutlet.hidden=YES;
    userButtonOutlet.hidden=NO;
    saveButtonOutlet.hidden=YES;
    myCounterLabel.text=nil;
    secondsLeft=0;
    NSLog(@"The cancel session seconds left %d", secondsLeft);
    [self stopTimer:nil];

}

-(NSInteger)collectionView:(UICollectionView *)view numberOfItemsInSection:(NSInteger)section;
{

    return 25;
}

- (NSInteger)numberOfSectionsInCollectionView: (UICollectionView *)collectionView
{
    return 1;
}

-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
    NSLog(@"item clicked");
    CGRect rect = [collectionView layoutAttributesForItemAtIndexPath:indexPath].frame;

    UIStoryboard* storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
    UIViewController* vc = [storyboard instantiateViewControllerWithIdentifier:@"note"];

    pc = [[UIPopoverController alloc] initWithContentViewController:vc];

    [pc presentPopoverFromRect:rect inView:collectionView
      permittedArrowDirections:UIPopoverArrowDirectionAny
                      animated:YES];
    NSLog(@" The index path is %@", indexPath);

}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    // we're going to use a custom UICollectionViewCell, which will hold an image and its label
    Cell *myCell = [collectionView dequeueReusableCellWithReuseIdentifier:@"TableCell"
                                                       forIndexPath:indexPath];

    if ((long)indexPath.row < 20 || (long)indexPath.row == 22 )
    {
        NSLog(@"case");
         myCell.roomLabel.text = [NSString stringWithFormat:@"{%ld,%ld}", (long)indexPath.row, (long)indexPath.section];

        NSLog(@"INDEX PATH %lu" , (long)indexPath.row );
        myCell.subjectLabel.text =@"English";
        myCell.cellView.backgroundColor= [UIColor grayColor];

         button=[[UIButton alloc]init];
       [button setFrame:CGRectMake(5,5,10,23)];
        [button setTitle:@"X" forState:UIControlStateNormal];
       [button addTarget:self action:@selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside];
    [button setHidden:NO];
      [myCell addSubview:button];

    }
   else
   {
       myCell.userInteractionEnabled = NO;

   }
    return myCell;
   }

Answer 1

你如何创建一个 BOOL 标志说:

@interface MyViewController
{
    BOOL shouldDisplayButton;
}

@end

然后将长按手势添加到整个 UICollectionView:

-(void)viewDidLoad
{
    [super viewDidLoad];
    ...

    UILongPressGestureRecognizer *longPress = [[UIGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPress:)];

    ...

    [self.myCollectionView addGestureRecognizer:longPress];
}

-(void)handleLongPress:(UILongPressGestureRecognizer *)longPressGesture
{
    // -------------------------------------------------------------------
    // we only want to trigger this if the user let go of the long press
    // otherwise, the long press will continuously execute this block
    // -------------------------------------------------------------------
    if(longPressGesture.state == UIGestureRecognizerStateEnded)
    {
        // ----------------------------------------------------------------
        // This basically toggles the boolean flag on and off then reload
        // your collection view. See your collectionView cellForRowAtIndex
        // where you enable the button based on the value of this boolean.
        // ----------------------------------------------------------------
        if(shouldDisplayButton)
        {
            shouldDisplayButton = NO;
        }
        else
        {
            shouldDisplayButton = YES;
        }

        [self.myCollectionView reloadData];
    }
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)cv cellForItemAtIndexPath:(NSIndexPath *)indexPath 
{
    ....

    button=[[UIButton alloc]init];
    [button setFrame:CGRectMake(5,5,10,23)];
    [button setTitle:@"X" forState:UIControlStateNormal];
    [button addTarget:self action:@selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside];

    [myCell addSubview:button];


    // ---------------------------------------------------------------------
    // Here you only hide your button if the BOOL flag is NO, otherwise,
    // you show your button.
    // ---------------------------------------------------------------------
    if(shouldDisplayButton)
    {
        [button setHidden:NO];
    }
    else
    {
        [button setHidden:YES];
    }
}

这有帮助吗？