以网格模式在 UIScrollView 中添加子视图

Posted 2023-03-12

【中文标题】以网格模式在 UIScrollView 中添加子视图

【英文标题】：Adding subviews in UIScrollView in a grid pattern

【发布时间】：2011-01-16 05:57:21

【问题描述】：

我将子视图添加到UIScrollView，（这是UIVewController），它们并没有像他们想象的那样形成2 x 2 网格。这是我正在使用的一些代码：

-(void)layoutSubviews

    BOOL blurbsHaveBorder = YES;

    int blurbCount = 3;
    int blurbsPerRow;

    int viewWidth = gridView.bounds.size.width;
    int viewHeight = gridView.bounds.size.height;

    int blurbWidth = 320;
    int blurbHeight = 320;

    int spaceWidth = round((viewWidth -blurbWidth * blurbsPerRow) / (blurbsPerRow + 1));
    int spaceHeight = spaceWidth;

    int rowCount = ceil(blurbCount / (float)blurbsPerRow);
    int rowHeight = blurbHeight + spaceHeight;


    if (blurbsPerRow < 1) blurbsPerRow = 1;


    NSInteger rowsPerView = viewHeight / rowHeight;
    NSInteger topRow = gridView.contentOffset.y / rowHeight;
    NSInteger bottomRow = topRow + rowsPerView;

    NSInteger startAtIndex = topRow * blurbsPerRow;
    NSInteger stopAtIndex = (bottomRow * blurbsPerRow) + blurbsPerRow;
    if (stopAtIndex > blurbCount) stopAtIndex = blurbCount;

    int x = spaceWidth;
    int y = spaceHeight + (topRow * rowHeight);

    int i;
    /*  add new subviews.  */ 
    for (int i = startAtIndex; i < stopAtIndex; i++) 
        if (i >= 0) 

            blurbItem = [[BlurbItem alloc] initWithFrame:CGRectMake(5,5,blurbWidth,blurbHeight) 
                                            andHasBorder:blurbsHaveBorder];

            [gridView addSubview:blurbItem.view];
            [blurbItem release];
           

    

    /*  adjust the position.  */
    if ( (i+1) % blurbsPerRow == 0) 
        /*  start new row.  */
        x = spaceWidth;
        y += blurbHeight + spaceHeight;
     else 
        x += blurbWidth + spaceWidth;
    

【参考方案1】：

我读对了吗？看起来您没有设置 blurbsPerRow。这会使其默认为 0 吗？

【讨论】：

我很惊讶你没有得到除以零的错误。另外，您无需先初始化就使用它。