Datasource for UITableViews in UIScrollView - iphone

Question

I'm working on the project using several UITableViews being put vertically next to each other. I got to show those tables, but got stuck when I tried to show different table contents for each table.
This is the code:
-(void)setTheTable{
int numberOfTables = 5;
//height of the table
CGFloat height = self.view.bounds.size.height;
CGRect tableBounds = CGRectMake(0.0f, 0.0f, self.widthOfTheScreen, height- 30);
self.scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0.0f, 30.0f, self.widthOfTheScreen, height - 30.0f)];
self.scrollView.contentSize = CGSizeMake(self.widthOfTheScreen * numberOfTables, height-30);
self.scrollView.pagingEnabled = YES;
self.scrollView.bounds = tableBounds;
[self.view addSubview:self.scrollView];
//put five tables
CGRect tableFrame = tableBounds;
tableFrame.origin.x = 0;
for (int i = 0; i < numberOfTables; i++) {
UITableView *tableView = [[UITableView alloc] initWithFrame:tableFrame style:UITableViewStylePlain];
tableView.delegate = self;
tableView.dataSource = self;
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell"];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"Cell"];
}
switch (i) {
case 0:
tableView.backgroundColor = [UIColor yellowColor];
tableView.tag = 0;
cell.textLabel.text = #"section = 0 行0";
break;
case 1:
tableView.backgroundColor = [UIColor blueColor];
tableView.tag = 1;
break;
case 2:
tableView.backgroundColor = [UIColor brownColor];
tableView.tag = 2;
break;
case 3:
tableView.backgroundColor = [UIColor greenColor];
break;
case 4:
tableView.backgroundColor = [UIColor cyanColor];
break;
default:
break;
}
[self.scrollView addSubview:tableView];
tableFrame.origin.x += self.widthOfTheScreen;
}
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 3;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell"];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"Cell"];
}
int num = tableView.tag;
if(num == 1) {
if(indexPath.row == 0) {
cell.textLabel.text = #"section = 0 行0";
} else if(indexPath.row == 1){
cell.textLabel.text = #"section = 0 行1";
} else {
cell.textLabel.text = #"section = 0 行2";
}
} else {
NSString *str = [[NSString alloc] initWithFormat:#"section = %d col %d",indexPath.section,indexPath.row];
cell.textLabel.text = str;
}
return cell;
}
I thought tableview.tag would help but gave me 5 same tables.
Could you guys give me some ideas to solve this problem?
Thank you.

Answer 1

First of all, see this answer about adding a UITableView to a UIScrollView, Apple specifically warns against it (though they did not include the warning in the UITableView docs, not your fault). Add your tables as subviews to a UIView NOT a UIScrollView (I recommend getting rid of that entriely).
Second, you only create a UITableViewCell in the tableView:cellForRowAtIndexPath: method. Remove all references to any UITableCell from your for-loop entirely (those are not even being used, it is work for nothing). After you have set the table's data source and delegate, call [tableView reloadData] on each able, the data source methods will be called automatically.
Since you are working with multiple tables, things get a bit more tricky. You will need to keep a reference to all your table views in your class (either in an array, but ideally properties for each table view).
You will also need to know what table is being loaded at any given time, e.g.:
-(UITableViewCell*)tablView:tableView cellForRowAtIndexPath:indexPath {
UITableViewCell *cell;
if ( tableView == self.tablView1 ) {
// build your cells for table view 1
}
else if ( tableView == self.tableView2 ) {
// build cells for table view 2
}
return cell;
}
With multiple tables, you would probably want to consider a specific delegate for each table, especially if the data models behind each table is vastly different, and/or each the UI for each table are different.
I do not know your exact needs, but also consider a table with multiple sections instead of multiple tables.
I also encourage you to read the iOS TableView Programming Guide, and this on Delegates and Data Sources.