如何将UIActivity指标添加到每个单元格并保持对每个指标的控制 [英] How do I add a UIActivity Indicator to every Cell and maintain control of each individual indicator

问题描述

我正在尝试向UITableView中的某些单元格添加活动指示器.我在使用

I'm trying to add an activity indicator to certain cells in my UITableView. I do this successfully in the method didSelectRowAtIndexpath using

    CGRect CellFrame = CGRectMake(260, 10, 20, 20);
    actindicator = [[UIActivityIndicatorView alloc]initWithFrame:CellFrame];
    [actindicator setHidesWhenStopped:NO];
    [actindicator setActivityIndicatorViewStyle:UIActivityIndicatorViewStyleGray];
    actindicator.tag =1;
    [[cell contentView] addSubview:actindicator];

问题是我需要通过另一种方法来控制这些多个活动指标.我认为属性是一种实现此目的的方法，但是每次都初始化一个新的actIndicator实例时，除了活动指示器的最新"初始化之外，我都松散了对所有引用的引用，因此，我只能控制一个.

The catch is I need to control these multiple activity indicators from ANOTHER METHOD. I figured a property was a way to do this however by initialising a new instance of actIndicator every time, I loose reference's to all but the 'latest' init of the activity indicator thus meaning I can only control one.

在这里(如果可能的话)我需要做些什么来保持对所有actIndicator的引用，以便我可以开始为所有actIndicator设置动画? 或者我可以以某种方式使用actindicator.tag来控制某种形式的引用.

What do i need to do here (if even possible?) to maintain reference to all the actIndicators so i can begin animating ALL of them? Or Can I somehow use the actindicator.tag to control some form of reference.

非常感谢您的帮助.

(从答案中得出)以访问tableView中标记为1的所有Activity指示器实例(仅可见单元格)可以通过另一种方法在下面使用:

(Derived from answer) to access all Instances of Activity indicator with a tag of 1 in tableView (visible cells only) can use below from another method:

for (UITableViewCell *cell in [self.tableView visibleCells]) {
    UIActivityIndicatorView *actView = (UIActivityIndicatorView *)[cell.contentView
    viewWithTag:1];
    [actView startAnimating];
    activityFlag = 1;

}

以上方法将循环遍历所有可见单元格并开始为活动指示器设置动画.

The method above will cycle through all visible cells and start animating the activity indicator.

要处理表格视图被滚动的情况，我使用cellForRowAtIndexPath中的以下方法对指示器重新设置了动画. cellStateKey只是表明该单元格旁边是否有一个选中标记，是否确实有一个选中标记，并且是否设置了我的activityflag(正在进行异步网络服务器调用).然后我要继续进行动画制作(从技术上重新启动动画，如滚动tableview)停止它)

To handle the case of the tableview being scrolled, I re-animate the indicators using the method below which is in cellForRowAtIndexPath. cellStateKey simply indicates if the cell has a checkmark next to it, if it does have a checkmark and my activityflag (async webserver call in progress)is set..then i want to continue animating.(technically re-start animation, as scrolling tableview stops it)

if ([[rowData objectForKey:cellStateKey] boolValue]) {

    cell.accessoryType = UITableViewCellAccessoryCheckmark;

      if(cell.accessoryType == UITableViewCellAccessoryCheckmark &&activityFlag ==1){

        for (UIView *sub in [[cell contentView] subviews]) {

            if (sub.tag == 1) {

                UIActivityIndicatorView *acView = (UIActivityIndicatorView *)
                [cell.contentView viewWithTag:1];
                [acView startAnimating];


            }

        }

如原始问题中所述，我在didSelectRowAtIndexPath方法中初始化了活动指标(并在需要时也删除了活动指标)

As mentioned in origional question I initialise my activity indicators (and remove activity indicators aswell if required) in the method didSelectRowAtIndexPath

推荐答案

一种简单的方法(假设您正在代码中添加指标)是首先获取可见单元格(或行)的集合在表中，通过调用[tableView visibleCells].然后像这样遍历单元格:

A simple way to do this (assuming you're adding the indicator as in your code) is to first get a collection of the visible cells (or rows) in your table, by calling [tableView visibleCells]. Then iterate through the cells like this:

for (UITableViewCell *cell in [tableView visibleCells]) {
    for (UIView *sub in [cell subViews]) {
        if (sub.tag == 1) { // "1" is not a good choice for a tag here
            UIActivityIndicatorView *act = (UIActivityIndicatorView *)sub;
            [act startAnimating]; // or whatever the command to start animating is
            break;
        }
    }
}

您需要处理的复杂性更高:在原始代码中，您需要确保没有在每次调用cellForRowAtIndexPath时都向现有单元格添加额外的活动指示器，并且需要考虑对于用户稍后可能会滚动表，暴露未打开活动指示器的单元格的情况.

There's more complexity for you to deal with: in your original code, you need to make sure you're not adding an additional activity indicator to a pre-existing cell each time cellForRowAtIndexPath is called, and you need to account for the situation where the user might scroll the table at a later point, exposing cells that do not have their activity indicator turned on.

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