iOS如何实现长按拖动控件_移动开发_编程开发_程序员俱乐部

　　实现控件拖动的方法有多种，可以使用UICollectionView的代理方法直接实现，但是有些开发者在初始时没有使用UICollectionView创建九宫格，后来增加需求，却要增加这种拖动移动的效果，又不想更改页面的初始控件，那么应该怎么实现呢？

　　方法很简单，首先在@interface创建以下全局变量；

@interface YRViewController ()
{
    BOOL contain;
     CGPoint startPoint;
     CGPoint originPoint;
   
}
@property (strong , nonatomic) NSMutableArray *itemArray;
@end

　　如图所示，在viewDidLoad里创建了如下的控件布局；

 1 - (void)viewDidLoad
 2 {
 3     [super viewDidLoad];
 4     
 5     for (NSInteger i = 0;i<8;i++)
 6     {
 7         UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
 8         btn.backgroundColor = [UIColor redColor];
 9         btn.frame = CGRectMake(50+(i%2)*100, 64+(i/2)*100, 90, 90);
10         btn.tag = i;
11         btn.titleLabel.font = [UIFont boldSystemFontOfSize:20];
12         [btn setTitle:[NSString stringWithFormat:@"%d",1+i] forState:UIControlStateNormal];
13         [self.view addSubview:btn];
14         UILongPressGestureRecognizer *longGesture = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(buttonLongPressed:)];
15         [btn addGestureRecognizer:longGesture];
16         [self.itemArray addObject:btn];
17 
18     }
19 }

　　下面，我们就要思考，如何实现长按移动了，控件的移动并且重新排序，主要是考虑移动的那个控件移动到新的位置，直接看下列代码，

class="brush:objc;gutter:true;">- (void)buttonLongPressed:(UILongPressGestureRecognizer *)sender
{

    UIButton *btn = (UIButton *)sender.view;
    if (sender.state == UIGestureRecognizerStateBegan)
    {
        startPoint = [sender locationInView:sender.view];
        originPoint = btn.center;
        [UIView animateWithDuration:Duration animations:^{
            
            btn.transform = CGAffineTransformMakeScale(1.1, 1.1);
            btn.alpha = 0.7;
        }];
       
    }
    else if (sender.state == UIGestureRecognizerStateChanged)
    {
        
        CGPoint newPoint = [sender locationInView:sender.view];
        CGFloat deltaX = newPoint.x-startPoint.x;
        CGFloat deltaY = newPoint.y-startPoint.y;
        btn.center = CGPointMake(btn.center.x+deltaX,btn.center.y+deltaY);
        //NSLog(@"center = %@",NSStringFromCGPoint(btn.center));
        NSInteger index = [self indexOfPoint:btn.center withButton:btn];
        if (index<0)
        {
            contain = NO;
        }
        else
        {
            [UIView animateWithDuration:Duration animations:^{
                
                CGPoint temp = CGPointZero;
                UIButton *button = _itemArray[index];
                temp = button.center;
                button.center = originPoint;
                btn.center = temp;
                originPoint = btn.center;
                contain = YES;

            }];
        }
        
        
    }
    else if (sender.state == UIGestureRecognizerStateEnded)
    {
        [UIView animateWithDuration:Duration animations:^{
            
           btn.transform = CGAffineTransformIdentity;
           btn.alpha = 1.0;
            if (!contain)
            {
                 btn.center = originPoint;
            }
        }];
    }
}


- (NSInteger)indexOfPoint:(CGPoint)point withButton:(UIButton *)btn
{
    for (NSInteger i = 0;i<_itemArray.count;i++)
    {
        UIButton *button = _itemArray[i];
        if (button != btn)
        {
            if (CGRectContainsPoint(button.frame, point))
            {
                return i;
            }
        }
    }
    return -1;
}

这样，我们通过位置判断的方式，让控件得以重新排列。