有没有更好的方法来确定UITableViewCell的正确大小？ [英] Is there a better way to determine the right size for a UITableViewCell?

问题描述

我有一个UITableView单元格，将有一个可变的大小，取决于它的内容（潜在的几行文字）。

I have a UITableView cell that is going to have a variable size depending on it's content (potentially several lines of text).

SInce看起来在之前调用了heightForRowAtIndexPath单元格，我通过在我的文本上调用[NSString sizeWithFont]来猜测正确的高度串。有没有更好的方法来设置高度之后我已经在单元格中的文本，并有一个想法是什么大小应该是什么？

SInce it appears that heightForRowAtIndexPath is called before I layout the cell, I just guess the correct height by calling [NSString sizeWithFont] on my text string. Is there a better way to set the height after I've laid out the text in the cell and have an idea of exactly what size it should be?

推荐答案

它会听起来很蠢，但...呃......在退出heightForRowAtIndexPath之前布局你的单元格;）

It's going to sound dumb, but ...uh... "layout your cell before you exit heightForRowAtIndexPath" ;)

很明显，虽然 - 操作系统只有在需要的时候才调用这个函数（如：创建单元格并在屏幕上显示它），因此，准备显示并不浪费人力。

Seriously, though -- the OS only ever calls this if it's going to be needed (as in: it's about to create the cell & display it on screen), so laying it out & getting ready to display is not wasted effort.

请注意，您需要不分开进行布局，逻辑方面。只需在您的heightForRowAtIndexPath例程中调用您的[self prepLayoutForCellAtIndex：index]。

Note, you do not have to do your layout separately, logic-wise. Just make a call to your [self prepLayoutForCellAtIndex:index] within your heightForRowAtIndexPath routine.

如果数据是静态的，您可以创建一个高度表并缓存信息。 / p>

If the data is static, you can create a height table and cache the info.

if (0 == heightTable[index]) {
    heightTable[index] = [self prepLayoutForCellAtIndex:index];
}
return (heightTable[index]);

即使数据更改，您也可以重新计算方法中的表值，数据，或清除为0，以便下次需要时重新计算。

Heck, even if the data changes, you can either recalculate the table value in the method that changes the data, or clear to 0 so it gets recalculated the next time it's needed.

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