iOS：使用insertRowsAtIndexPaths在UITableview中插入多行 [英] iOS : Inserting multiple rows in UITableview with insertRowsAtIndexPaths

问题描述

我在TableView中已有10行我想要做的是添加另外10行，因为我使用的是insertRowsAtIndexPaths，但是我收到了错误。

I have already 10 rows in TableView What I am trying to do is adding another 10 rows for that I am using insertRowsAtIndexPaths but I am getting errors.

以下是我正在使用的代码

Following is the code I am using

-(void)insertDownloadedActions:(NSMutableArray *)dataToAdd
{
        __weak CurrentViewController *weakSelf = self;

        int64_t delayInSeconds = 2.0;
        dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
        dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
            [weakSelf.tableView beginUpdates];
            [weakSelf.dataSource addObjects:dataToAdd];
            NSIndexPath *newIndexPath = [NSIndexPath indexPathForRow:[weakSelf.dataSource count]-dataToAdd.count-1 inSection:0];
            [weakSelf.tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationTop];
            [weakSelf.tableView endUpdates];
        });
}

但是我收到了以下错误

Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of rows in section 0.  The number of rows contained in an existing section after the update (20) must be equal to the number of rows contained in that section before the update (10), plus or minus the number of rows inserted or deleted from that section (1 inserted, 0 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out).

推荐答案

代码已关闭，但表视图需要使用与添加到数据源的内容完全对应的索引路径进行更新。

The code is close, but the table view needs to be updated with index paths in exact correspondence with what's added to the datasource.

-(void)insertDownloadedActions:(NSMutableArray *)dataToAdd
{
    // don't need this
    //__weak CurrentViewController *weakSelf = self;

    int64_t delayInSeconds = 2.0;
    dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
    dispatch_after(popTime, dispatch_get_main_queue(), ^(void) {

        // build the index paths for insertion
        // since you're adding to the end of datasource, the new rows will start at count
        NSMutableArray *indexPaths = [NSMutableArray array];
        NSInteger currentCount = self.datasource.count;
        for (int i = 0; i < dataToAdd.count; i++) {
            [indexPaths addObject:[NSIndexPath indexPathForRow:currentCount+i inSection:0]];
        }

        // do the insertion
        [self.dataSource addObjects:dataToAdd];

        // tell the table view to update (at all of the inserted index paths)
        [self.tableView beginUpdates];
        [self.tableView insertRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationTop];
        [self.tableView endUpdates];
    });
}

您希望weakSelf避免块所有者保留块的周期block（通过使用块所有者self）保留所有者。这里不需要weakSelf模式，因为视图控制器没有保留调度块的副本。

You want a weakSelf to avoid cycle where the block owner retains the block and the block (by using the block owner "self") retains the owner. There's no need for the weakSelf pattern here since the view controller is not retaining a copy of the dispatched block.

这篇关于iOS：使用insertRowsAtIndexPaths在UITableview中插入多行的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！