我正在构建一个应用程序，其中 UIImageView 以编程方式遍历 UITableView。我创建了两个按钮（“向上”和“向下”）来控制 UIImageView 移动的方向。如果 UIImageView 向上/向下移动到当前不可见的行，我想要做的是以编程方式滚动 UITableView。我意识到我需要使用 UITableView 方法“visibleCells”来检查单元格是否在返回的数组中。如果单元格不在数组中，那么我需要将表格向上/向下滚动精确一行（每次用户单击“向上”/“向下”按钮时）。不幸的是，我没有遇到任何关于如何使用该方法的好例子，我需要帮助。这是我在这里的代码：
- (IBAction)buttonClicked:(id)sender {
if([sender tag] == 1){
//here is where I will need to make the call to [_tableView visibleCells] to see if the cell that the UIImageView is about to scroll up to is within this array. If not, then programmatically scroll up one row.
if (_index.row == 0) {
_index = [NSIndexPath indexPathForRow:[_tableData count] - 1 inSection:_index.section];
[_table scrollToRowAtIndexPath:_index atScrollPosition:UITableViewScrollPositionTop animated:YES];
}
else
_index = [NSIndexPath indexPathForRow:_index.row - 1 inSection:_index.section];
[UIView animateWithDuration:.3 animations:^{
CGRect rect = [self.view convertRect:[_table rectForRowAtIndexPath:_index] fromView:_table];
CGFloat floatx = _imageView.frame.origin.x - rect.origin.x;
_imageView.frame = CGRectMake(rect.origin.x + floatx, rect.origin.y, _imageView.frame.size.width, _imageView.frame.size.height);
}];
}
else if([sender tag] == 2){
if (_index.row + 1 == [_tableData count]) {
_index = [NSIndexPath indexPathForRow:0 inSection:_index.section];
[_table scrollToRowAtIndexPath:_index atScrollPosition:UITableViewScrollPositionBottom animated:YES];
}
else
_index = [NSIndexPath indexPathForRow:_index.row + 1 inSection:_index.section];
[UIView animateWithDuration:.3 animations:^{
CGRect rect = [self.view convertRect:[_table rectForRowAtIndexPath:_index] fromView:_table];
CGFloat floatx = _imageView.frame.origin.x - rect.origin.x;
_imageView.frame = CGRectMake(rect.origin.x + floatx, rect.origin.y, _imageView.frame.size.width, _imageView.frame.size.height);
}];
}
}
谁能告诉我如何完成我想要实现的功能？
