iOS : Inserting multiple rows in UITableview with insertRowsAtIndexPaths

Question

我在 TableView 中已经有 10 行我正在尝试做的是添加另外 10 行，因为我正在使用 insertRowsAtIndexPaths 但我收到错误。

下面是我使用的代码

-(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];
        });
}

但我收到以下错误

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).

Answer 1

代码很接近，但 TableView 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。

-(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 避免这样的循环，即 block 所有者保留 block 而 block (通过使用 block 所有者“self”)保留所有者。这里不需要 weakSelf 模式，因为 View Controller 不保留分派(dispatch) block 的副本。