iOS 拖拽式控件：QiDragView

首先，我们先看一下QiDragView的效果图： 

一、QiDragView整体架构设计

话不多说，上架构图~

QiDragView（QiDragSortView）是一种可选择可拖拽的自定义控件，可以满足一些拖拽排序的业务需求场景。

二、如何自定义使用QiDragView？

在上Demo之前，先介绍几个可以自定义的UI配置属性：

以及一些逻辑配置属性：

使用起来也很方便：

• 直接设置titles即可创建出对应title的Buttons。
• 通过dragSortEnded的block方法回调，处理拖拽后的业务逻辑：按钮的排序、按钮是否选择等属性

默认配置用法：

QiDragSortView *dragSortView = [[QiDragSortView alloc] initWithFrame:CGRectMake(.0, 100.0, self.view.bounds.size.width, .0)];
dragSortView.backgroundColor = [[UIColor lightGrayColor] colorWithAlphaComponent:.5];

dragSortView.titles = @[@"首页推荐", @"奇舞周刊", @"众成翻译", @"QiShare", @"HULK一线杂谈", @"Qtest之道"];//!< 初始的Buttons（必填）
[self.view addSubview:dragSortView];

//! 拖拽方法回调：能拿到Button数组的排序和选择状态
dragSortView.dragSortEnded = ^(NSArray<UIButton *> * _Nonnull buttons) {
    for (UIButton *button in buttons) {
        NSLog(@"title: %@, selected: %i", button.currentTitle, button.isSelected);
    }
};

自定义配置用法：

QiDragSortView *dragSortView = [[QiDragSortView alloc] initWithFrame:CGRectMake(.0, 100.0, self.view.bounds.size.width, .0)];
dragSortView.backgroundColor = [[UIColor lightGrayColor] colorWithAlphaComponent:.5];
dragSortView.rowHeight = 50.0;
dragSortView.rowMargin = 30.0;
dragSortView.rowPadding = 20.0;
dragSortView.columnCount = 3;
dragSortView.columnMargin = 30.0;
dragSortView.columnPadding = 20.0;
dragSortView.normalColor = [UIColor redColor];
dragSortView.selectedColor = [UIColor purpleColor];
dragSortView.enabledTitles = @[@"奇舞周刊", @"众成翻译", @"QiShare", @"HULK一线杂谈", @"Qtest之道"];//!< 可以点击选择的Buttons（选填，默认全选）
dragSortView.selectedTitles = @[@"首页推荐", @"HULK一线杂谈", @"Qtest之道"];//!< 初始选择的Buttons（选填，默认全选）
dragSortView.titles = @[@"首页推荐", @"奇舞周刊", @"众成翻译", @"QiShare", @"HULK一线杂谈", @"Qtest之道"];//!< 初始的Buttons（必填）
[self.view addSubview:dragSortView];

//! 拖拽方法回调：能拿到Button数组的排序和选择状态
dragSortView.dragSortEnded = ^(NSArray<UIButton *> * _Nonnull buttons) {
    for (UIButton *button in buttons) {
        NSLog(@"title: %@, selected: %i", button.currentTitle, button.isSelected);
    }
};

三、QiDragView的技术点

3.1 长按手势：

长按手势分别对应三种状态：UIGestureRecognizerStateBegan、UIGestureRecognizerStateChanged、UIGestureRecognizerStateEnded。

//! 长按手势
- (void)longPress:(UILongPressGestureRecognizer *)gesture {
    
    UIButton *currentButton = (UIButton *)gesture.view;
    
    if (gesture.state == UIGestureRecognizerStateBegan) {
        
        [self bringSubviewToFront:currentButton];
        
        [UIView animateWithDuration:.25 animations:^{
            self.originButtonCenter = currentButton.center;
            self.originGesturePoint = [gesture locationInView:currentButton];
            currentButton.transform = CGAffineTransformScale(currentButton.transform, 1.2, 1.2);
        }];
    }
    else if (gesture.state == UIGestureRecognizerStateEnded) {
        
        [UIView animateWithDuration:.25 animations:^{
            currentButton.center = self.originButtonCenter;
            currentButton.transform = CGAffineTransformIdentity;
        } completion:^(BOOL finished) {
            if (self.dragSortEnded) {
                self.dragSortEnded(self.buttons);
            }
        }];
    }
    else if (gesture.state == UIGestureRecognizerStateChanged) {
        
        CGPoint gesturePoint = [gesture locationInView:currentButton];
        CGFloat deltaX = gesturePoint.x - _originGesturePoint.x;
        CGFloat deltaY = gesturePoint.y - _originGesturePoint.y;
        currentButton.center = CGPointMake(currentButton.center.x + deltaX, currentButton.center.y + deltaY);
        
        NSInteger fromIndex = currentButton.tag;
        NSInteger toIndex = [self toIndexWithCurrentButton:currentButton];
        
        if (toIndex >= 0) {
            currentButton.tag = toIndex;
            
            if (toIndex > fromIndex) {
                for (NSInteger i = fromIndex; i < toIndex; i++) {
                    UIButton *nextButton = _buttons[i + 1];
                    CGPoint tempPoint = nextButton.center;
                    [UIView animateWithDuration:.5 animations:^{
                        nextButton.center = self.originButtonCenter;
                    }];
                    _originButtonCenter = tempPoint;
                    nextButton.tag = i;
                }
            }
            else if (toIndex < fromIndex) {
                for (NSInteger i = fromIndex; i > toIndex; i--) {
                    UIButton *previousButton = self.buttons[i - 1];
                    CGPoint tempPoint = previousButton.center;
                    [UIView animateWithDuration:.5 animations:^{
                        previousButton.center = self.originButtonCenter;
                    }];
                    _originButtonCenter = tempPoint;
                    previousButton.tag = i;
                }
            }
            [_buttons sortUsingComparator:^NSComparisonResult(UIButton *obj1, UIButton *obj2) {
                return obj1.tag > obj2.tag;
            }];
        }
    }
}

3.2 配置按钮：

设计思路：在属性titles的setter方法中，初始化并配置好各个Buttons。

- (void)setTitles:(NSArray<NSString *> *)titles {
    
    _titles = titles;
    
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(.01 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        NSInteger differCount = titles.count - self.buttons.count;
        
        if (differCount > 0) {
            for (NSInteger i = self.buttons.count; i < titles.count; i++) {
                [self.buttons addObject:[self buttonWithTag:i]];
            }
        }
        else if (differCount < 0) {
            NSArray *extraButtons = [self.buttons subarrayWithRange:(NSRange){titles.count, self.buttons.count - titles.count}];
            [self.buttons removeObjectsInArray:extraButtons];
            for (UIButton *button in extraButtons) {
                [button removeFromSuperview];
            }
        }
        
        self.enabledTitles = self.enabledTitles ?: titles;//!< 如果有，就传入，否则传入titles
        self.selectedTitles = self.selectedTitles ?: titles;
        
        for (NSInteger i = 0; i < self.buttons.count; i++) {
            [self.buttons[i] setTitle:titles[i] forState:UIControlStateNormal];
            [self.buttons[i] addGestureRecognizer:[[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPress:)]];//!< 长按手势
            [self selectButton:self.buttons[i] forStatus:[self.selectedTitles containsObject:titles[i]]];
            if ([self.enabledTitles containsObject:titles[i]]) {
                [self.buttons[i] addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
            }
        }
        
        for (NSInteger i = 0; i < self.buttons.count; i++) {
            NSInteger rowIndex = i / self.columnCount;
            NSInteger columnIndex = i % self.columnCount;
            CGFloat buttonWidth = (self.bounds.size.width - self.columnMargin * 2 - self.columnPadding * (self.columnCount - 1))  / self.columnCount;
            CGFloat buttonX = self.columnMargin + columnIndex * (buttonWidth + self.columnPadding);
            CGFloat buttonY = self.rowMargin + rowIndex * (self.rowHeight + self.rowPadding);
            self.buttons[i].frame = CGRectMake(buttonX, buttonY, buttonWidth, self.rowHeight);
        }
        
        CGRect frame = self.frame;
        NSInteger rowCount = ceilf((CGFloat)self.buttons.count / (CGFloat)self.columnCount);
        frame.size.height = self.rowMargin * 2 + self.rowHeight * rowCount  + self.rowPadding * (rowCount - 1);
        self.frame = frame;
    });
}

源码地址：QiDragView