ios - 控制可能会达到非无效功能

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what if when two UITableView in one ViewController and one with custom cell refrence and another is a simple
                                
                                    （6个答案）
                                
                        
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随附的代码返回错误：

Control may reach end non-void function

码：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    if (indexPath.row == 0) {
        FirstCustomCell *fCustomCell = [tableView dequeueReusableCellWithIdentifier:@"firstCustomCell" forIndexPath:indexPath];

        if (fCustomCell == nil) {

            fCustomCell = [[FirstCustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"firstCustomCell"];
        }

        return fCustomCell;

    }

    else if (indexPath.row == 1) {
        SecondCustomCell *sCustomCell = [tableView dequeueReusableCellWithIdentifier:@"secondCustomCell" forIndexPath:indexPath];

        if (sCustomCell == nil) {

            sCustomCell = [[SecondCustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"SecondCustomCell"];
        }

        return sCustomCell;

    }
} //<-- Control may reach non-void function (I precise that's the end of the cellForRowAtIndexPath method)

我知道问题特别在“返回”时出现，但是如何消除错误？

最佳答案

您要考虑indexPath.row == 0和indexPath.row == 1的情况，但是编译器会说：如果行不是0或1，我应该返回什么？

您可能在方法末尾需要return nil;。

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (indexPath.row == 0)
    {
        FirstCustomCell *fCustomCell = [tableView dequeueReusableCellWithIdentifier:@"firstCustomCell" forIndexPath:indexPath];
        if (fCustomCell == nil)
        {
            fCustomCell = [[FirstCustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"firstCustomCell"];
        }
        return fCustomCell;
    }
    else if (indexPath.row == 1)
    {
        SecondCustomCell *sCustomCell = [tableView dequeueReusableCellWithIdentifier:@"secondCustomCell" forIndexPath:indexPath];
        if (sCustomCell == nil)
        {
            sCustomCell = [[SecondCustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"secondCustomCell"];
        }
        return sCustomCell;
    }
    return nil; //<--Add this line
}

或“其他”情况：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (indexPath.row == 0)
    {
        FirstCustomCell *fCustomCell = [tableView dequeueReusableCellWithIdentifier:@"firstCustomCell" forIndexPath:indexPath];
        if (fCustomCell == nil)
        {
            fCustomCell = [[FirstCustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"firstCustomCell"];
        }
        return fCustomCell;
    }
    else if (indexPath.row == 1)
    {
        SecondCustomCell *sCustomCell = [tableView dequeueReusableCellWithIdentifier:@"secondCustomCell" forIndexPath:indexPath];
        if (sCustomCell == nil)
        {
            sCustomCell = [[SecondCustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"secondCustomCell"];
        }
        return sCustomCell;
    }
    else //<--Add this clause
    {
        OtherCustomCell *oCustomCell = [tableView dequeueReusableCellWithIdentifier:@"otherCustomCell" forIndexPath:indexPath];
        if (oCustomCell == nil)
        {
            oCustomCell = [[OtherCustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"otherCustomCell"];
        }
        return sCustomCell;
    }
}

注意：重用标识符中也有错字：

"secondCustomCell"与"SecondCustomCell"不同

关于ios - 控制可能会达到非无效功能，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/27742523/