iOS:使用insertRowsAtIndexPaths在UITableview中插入多行

Question

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.

以下是我正在使用的代码

-(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];
        });
}

但是我得到了以下错误

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).

Answer 1

代码很接近,但是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.

-(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避免循环,其中块所有者保留块,并且块(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.

Answer 2

在 swift 中，要添加多行，我们可以这样做

let indexPaths = (0 ..< messageList.count).map { IndexPath(row: $0, section: 0) }
self.chatTableView.beginUpdates()
self.chatTableView.insertRows(at: indexPaths, with: .bottom)
self.chatTableView.endUpdates()

我在这里插入，indexPath:0因为我想在向上滚动时附加列表。（反向分页）