iOS | PNChart与UITableView的联动

效果图

效果图.gif

1.点击chart，tableView对应模块高亮

PNChart提供了一个代理方法，用来处理用户的点击事件：

#pragma mark - PNChart Delegate
- (void)userClickedOnPieIndexItem:(NSInteger)pieIndex {
    for (int i = 0; i < self.model.department_sale.count; i++) {
        CQSaleDetailDepartmentItemModel *model = self.model.department_sale[i];
        model.selected = (i == pieIndex);
    }
    [self.tableView reloadData];
    [self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:pieIndex inSection:0] atScrollPosition:UITableViewScrollPositionMiddle animated:YES];
}

2.点击cell，chart对应模块高亮

PNChart并未提供相应方法让某一模块高亮，怎么办？

思路：

虽然PNChart未直接提供让某一模块高亮的方法，但是我们可以从用户点击模块高亮那部分代码入手，看看用户点击到模块高亮是怎样一个过程。

1.在PNPieChart.m里面找到touchesBegan方法：

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    for (UITouch *touch in touches) {
        CGPoint touchLocation = [touch locationInView:_contentView];
        [self didTouchAt:touchLocation];
    }
}

发现它调用了didTouchAt:方法。

2.分析didTouchAt:

- (void)didTouchAt:(CGPoint)touchLocation
{
    CGPoint circleCenter = CGPointMake(_contentView.bounds.size.width/2, _contentView.bounds.size.height/2);
    
    CGFloat distanceFromCenter = sqrtf(powf((touchLocation.y - circleCenter.y),2) + powf((touchLocation.x - circleCenter.x),2));
    
    if (distanceFromCenter < _innerCircleRadius) {
        if ([self.delegate respondsToSelector:@selector(didUnselectPieItem)]) {
            [self.delegate didUnselectPieItem];
        }
        [self.sectorHighlight removeFromSuperlayer];
        return;
    }
    
    CGFloat percentage = [self findPercentageOfAngleInCircle:circleCenter fromPoint:touchLocation];
    int index = 0;
    while (percentage > [self endPercentageForItemAtIndex:index]) {
        index ++;
    }
    
    if ([self.delegate respondsToSelector:@selector(userClickedOnPieIndexItem:)]) {
        [self.delegate userClickedOnPieIndexItem:index];
    }
    
    if (self.shouldHighlightSectorOnTouch)
    {
        if (!self.enableMultipleSelection)
        {
            if (self.sectorHighlight)
                [self.sectorHighlight removeFromSuperlayer];
        }
        
        PNPieChartDataItem *currentItem = [self dataItemForIndex:index];
        
        CGFloat red,green,blue,alpha;
        UIColor *old = currentItem.color;
        [old getRed:&red green:&green blue:&blue alpha:α];
        alpha /= 2;
        UIColor *newColor = [UIColor colorWithRed:red green:green blue:blue alpha:alpha];
        
        CGFloat startPercentage = [self startPercentageForItemAtIndex:index];
        CGFloat endPercentage   = [self endPercentageForItemAtIndex:index];
        
        self.sectorHighlight = [self newCircleLayerWithRadius:_outerCircleRadius + 5
                                                  borderWidth:10
                                                    fillColor:[UIColor clearColor]
                                                  borderColor:newColor
                                              startPercentage:startPercentage
                                                endPercentage:endPercentage];
        
        if (self.enableMultipleSelection)
        {
            NSString *dictIndex = [NSString stringWithFormat:@"%d", index];
            CAShapeLayer *indexShape = [self.selectedItems valueForKey:dictIndex];
            if (indexShape)
            {
                [indexShape removeFromSuperlayer];
                [self.selectedItems removeObjectForKey:dictIndex];
            }
            else
            {
                [self.selectedItems setObject:self.sectorHighlight forKey:dictIndex];
                [_contentView.layer addSublayer:self.sectorHighlight];
            }
        }
        else
        {
            [_contentView.layer addSublayer:self.sectorHighlight];
        }
    }
}

通过源代码我们可以发现，用户点击chart的时候，将传入的参数touchLocation转换成了index，这个index正是代理方法userClickedOnPieIndexItem:所需要的参数。另外，chart的某一模块高亮，实际上是addSublayer:，而这个sublayer的属性也是由index决定的。所以，通过主动调用一个方法让chart的某个模块高亮，关键就是这个index。

这样的话，就很简单了。只需把didTouchAt :的后半段代码提出来，就是我们需要的新方法了：

/**
 某一模块高亮
 @param index 高亮模块的index
 */
- (void)highlightItemWithIndex:(NSInteger)index {
    if (self.shouldHighlightSectorOnTouch)
    {
        if (!self.enableMultipleSelection)
        {
            if (self.sectorHighlight)
                [self.sectorHighlight removeFromSuperlayer];
        }
        
        PNPieChartDataItem *currentItem = [self dataItemForIndex:index];
        
        CGFloat red,green,blue,alpha;
        UIColor *old = currentItem.color;
        [old getRed:&red green:&green blue:&blue alpha:α];
        alpha /= 2;
        UIColor *newColor = [UIColor colorWithRed:red green:green blue:blue alpha:alpha];
        
        CGFloat startPercentage = [self startPercentageForItemAtIndex:index];
        CGFloat endPercentage   = [self endPercentageForItemAtIndex:index];
        
        self.sectorHighlight = [self newCircleLayerWithRadius:_outerCircleRadius + 5
                                                  borderWidth:10
                                                    fillColor:[UIColor clearColor]
                                                  borderColor:newColor
                                              startPercentage:startPercentage
                                                endPercentage:endPercentage];
        
        if (self.enableMultipleSelection)
        {
            NSString *dictIndex = [NSString stringWithFormat:@"%ld", (long)index];
            CAShapeLayer *indexShape = [self.selectedItems valueForKey:dictIndex];
            if (indexShape)
            {
                [indexShape removeFromSuperlayer];
                [self.selectedItems removeObjectForKey:dictIndex];
            }
            else
            {
                [self.selectedItems setObject:self.sectorHighlight forKey:dictIndex];
                [_contentView.layer addSublayer:self.sectorHighlight];
            }
        }
        else
        {
            [_contentView.layer addSublayer:self.sectorHighlight];
        }
    }
}

现在就可以实现点击cell，chart对应模块高亮了：

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    for (int i = 0; i < self.model.department_sale.count; i++) {
        CQSaleDetailDepartmentItemModel *model = self.model.department_sale[i];
        model.selected = (i == indexPath.row);
    }
    [self.tableView reloadData];
    [self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:indexPath.row inSection:0] atScrollPosition:UITableViewScrollPositionMiddle animated:YES];
    // 对应的模块高亮
    [self.pieChart highlightItemWithIndex:indexPath.row];
}

修改源码注意事项

如果你的PNChart是手动拖进去的，修改源码无所谓；

但如果是用CocoaPods管理的话，就要注意一下了：pod update的时候会覆盖你写的代码。为避免这种事情发生，你可以指定库的版本，如：

pod 'PNChart','0.8.9'

pod update的时候，若发现其版本是指定的版本，就不会更新了。

作者：无夜之星辰

链接：https://www.jianshu.com/p/759ea22a2a0f