iOS如何?長按拖動控制項，ios拖動控制項

iOS如何?長按拖動控制項，ios拖動控制項

　　實現控制項拖動的方法有多種，可以使用UICollectionView的代理方法直接實現，但是有些開發人員在初始時沒有使用UICollectionView建立九宮格，後來增加需求，卻要增加這種拖動移動的效果，又不想更改頁面的初始控制項，那麼應該怎麼實現呢？

　　方法很簡單，首先在@interface建立以下全域變數；

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

　　，在viewDidLoad裡建立了如下的控制項布局；

 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，我們就要思考，如何?長按移動了，控制項的移動並且重新排序，主要是考慮移動的那個控制項移動到新的位置，直接看下列代碼，

- (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;}

 

這樣，我們通過位置判斷的方式，讓控制項得以重新排列。