调用 ReloadData 时 UITableView 绘制问题-移动开发问题

UITableView Drawing Problems When ReloadData Is Called(调用 ReloadData 时 UITableView 绘制问题)

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问题描述

我有一个非常大的项目"列表(最多 250 个条目)，并且不断变化.该列表正在 UITableView 中显示.

我有一个轮询线程，它将下载一些新条目并将它们插入 SQLite DB.

当新条目到达时，我调用我的表视图数据源对象来更新它的数据集，它运行一个 SQL 查询并返回一个新的条目数组.

完成后，我在表格视图上调用 -reloadData.发生这种情况时，在 10 种情况下大约有 7 种情况下，表格视图绘制为空白(不显示单元格，只有表格的背景颜色可见)，直到进行后续的 -reloadData 调用.触摸表格视图(滚动、选择单元格、任何会强制重绘的内容)将使其重新出现.

表格视图、它的 IBOutlet 指针和当前显示的单元格在我看到空白绘图错误时都是有效的，所以我相当有信心它们没有被释放.

这几天我一直在尝试调试它，但它真的开始让我陷入困境.

在这方面的任何帮助都会非常棒，谢谢.

解决方案

如果你做一个 [ myTable performSelectorOnMainThread:@selector(reloadData) withObject:nil waitUntilDone:NO] 会有帮助吗?p>

如果您不从主线程操作您的 GUI 更新，则可能会出现您提到的问题.

I have a pretty large list of 'items' (up to 250 entries) which is constantly changing. The list is being displayed in a UITableView.

I have a polling thread that will download some new entries and insert them into a SQLite DB.

When new entries have arrived, I call to my table view data source object to update its data set, which runs a SQL query and returns a new array of entries.

After this is complete, I call -reloadData on the table view. When this happens, in about 7 out of 10 cases, the table view draws blank (no cells are displayed and only the background colour of the table is visible) until a subsequent -reloadData call is made. Touching the table view (scrolling, selecting a cell, anything that will force a redraw) will make it reappear.

The table view, its IBOutlet pointer and it's currently displayed cells are all valid at the times I see the blank drawing bug, so I'm fairly confident that they're not being released.

I've been trying to debug this for a few days now and it's really beginning to drive me up the wall.

Any help on this would be freaking awesome, thanks.

解决方案

Will it help if you do a [ myTable performSelectorOnMainThread:@selector(reloadData) withObject:nil waitUntilDone:NO] ?

The problem you mentioned can arise if you do not action your GUI updates from the main thread.

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