iOS 中的 Apple 喜欢在 UICollectionView 中摇动图标？

Question

我想开发一个项目应显示为 UICollectionView 的应用程序。当用户点击并按住项目时，所有项目都应该像 Apple 主屏幕一样开始摇晃，当我们想要删除应用程序时，图标开始摇晃。所以请告诉我如何实现此功能。有什么图书馆可以用吗？

Answer 1

首先声明你的变量：

UIButton* _deleteButton;
CGPoint p;  // It is a point which will give you which cell has been selected.

添加UIGestureRecognizerDelegate.

在 .m 文件中，在 viewDidLoad 中，将 UILongPressGestureRecognizer 和 UITapGestureRecognizer 添加到您的 collectionView，因为您想要在长按时摇动单元格:

- (void)viewDidLoad {
    [super viewDidLoad];

    // Add gesture recognizer to your collection view cell
    UILongPressGestureRecognizer *lpgr
    = [[UILongPressGestureRecognizer alloc]
       initWithTarget:self action:@selector(handleLongPress:)];
    lpgr.minimumPressDuration = .3; // To detect after how many seconds you want shake the cells
    lpgr.delegate = self;
    [self.collectionView addGestureRecognizer:lpgr];

    lpgr.delaysTouchesBegan = YES;

    /// This will be helpful to restore the animation when clicked outside the cell
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]
    initWithTarget:self action:@selector(handleTap:)];
    //lpgr.minimumPressDuration = .3; //seconds
    tap.delegate = self;
    [self.collectionView addGestureRecognizer:tap];

}

您现在可以在 .m 文件中实施 handleLongPress:。当您长按 collectionViewCell 时，您将获得用户按下单元格位置的 (x,y) 坐标，我们会将其存储在点 p.

中

基于这一点，您将能够获取适当单元格的适当 indexPath。

p = [gestureRecognizer locationInView:self.collectionView]; // Store (x,y) co-ordinate where the user has tapped the cell in point p.

NSIndexPath *indexPath = [self.collectionView indexPathForItemAtPoint:p];

现在，使用 QuartzCore 框架的 CABasicAnimation 为单元格添加动画。在动画的时候，把你的 _deleteButton 调高，这样它就可见了。

使用 handleTap:，您将能够在 collectionViewCell 之外单击时恢复动画。

-(void)handleTap:(UITapGestureRecognizer *)gestureRecognizer
{
    NSLog(@"singleTap");
    if (gestureRecognizer.state != UIGestureRecognizerStateEnded) {
        return;
    }
    p = [gestureRecognizer locationInView:self.collectionView];

    NSIndexPath *indexPath = [self.collectionView indexPathForItemAtPoint:p];
    if (indexPath == nil){
        NSLog(@"couldn't find index path");
        [[NSUserDefaults standardUserDefaults]setValue:@"no" forKey:@"longPressed"];
        [[NSUserDefaults standardUserDefaults]setValue:@"yes" forKey:@"singleTap"];
        //_deleteButton = [[UIButton alloc] initWithFrame:CGRectZero];
        //[cell addSubview:_deleteButton];
        //[_deleteButton removeFromSuperview];
        [self.collectionView reloadData];

    } else {

    }

}
-(void)handleLongPress:(UILongPressGestureRecognizer *)gestureRecognizer
{
    if (gestureRecognizer.state != UIGestureRecognizerStateEnded) {
        return;
    }
    p = [gestureRecognizer locationInView:self.collectionView];

    NSIndexPath *indexPath = [self.collectionView indexPathForItemAtPoint:p];
    if (indexPath == nil){
        NSLog(@"couldn't find index path");
    } else {

        [[NSUserDefaults standardUserDefaults]setValue:@"yes" forKey:@"longPressed"];
        [self.collectionView reloadData];

    }
}

根据所选项目，删除相应的项目。

-(void)deleteyourItem
{
    NSIndexPath *indexPath = [self.collectionView indexPathForItemAtPoint:p];
    //delete your item based on the `indexpath` from your collectionViewArray here.
    //OR If you are accessing the database to display the collectionView, you can compare the value fetched based on the `indexPath`, with your database value and then delete it.

    // Reload your collectionView after deletion
}

重新加载集合视图后，cellForItemAtIndexPath: 将如下所示：

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


    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"favoritecell" forIndexPath:indexPath];
   // UIImageView *img=[[UIImageView alloc]init];

    cell.backgroundColor = [UIColor colorWithRed:251.0/255.0 green:144.0/255.0 blue:13.0/255.0 alpha:1.0];


    //img.image = [UIImage imageNamed:@""];

    NSLog(@"%d",indexPath.row);


    if([[[NSUserDefaults standardUserDefaults]valueForKey:@"longPressed"] isEqualToString:@"yes"])
    {
        CABasicAnimation* anim = [CABasicAnimation animationWithKeyPath:@"transform.rotation"];
        [anim setToValue:[NSNumber numberWithFloat:0.0f]];
        [anim setFromValue:[NSNumber numberWithDouble:M_PI/64]];
        [anim setDuration:0.1];
        [anim setRepeatCount:NSUIntegerMax];
        [anim setAutoreverses:YES];
        cell.layer.shouldRasterize = YES;
        [cell.layer addAnimation:anim forKey:@"SpringboardShake"];
        CGFloat delButtonSize = 75;

        _deleteButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, delButtonSize, delButtonSize)];
        _deleteButton.center = CGPointMake(0, 0);
        _deleteButton.backgroundColor = [UIColor clearColor];

        [_deleteButton setImage: [UIImage imageNamed:@"delete.png"] forState:UIControlStateNormal];
        [cell addSubview:_deleteButton];

        [_deleteButton addTarget:self action:@selector(deleteRecipe) forControlEvents:UIControlEventTouchUpInside];

    }

    else if ([[[NSUserDefaults standardUserDefaults]valueForKey:@"singleTap"] isEqualToString:@"yes"])
    {

        for(UIView *subview in [cell subviews]) {
            if([subview isKindOfClass:[UIButton class]]) {
                [subview removeFromSuperview];
            } else {
                // Do nothing - not a UIButton or subclass instance
            }
        }
            [cell.layer removeAllAnimations];
//            _deleteButton.hidden = YES;
//            [_deleteButton removeFromSuperview];


    }

    //251, 144 , 13


    return cell;

}

iOS 中的 Apple 喜欢在 UICollectionView 中摇动图标？

Apple like shaking icons in UICollectionView in iOS?

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