UITableViewController委托

Question

I have a UITableViewController class that I call "MasterViewController". From within MasterViewController I want to display a tableview that uses a different UITableViewController (not MasterViewController). I am doing this as another tableview is already using MasterViewController as its delegate and datasource.

I have the following logic in a method of MasterViewController;

ToTableViewController *toController = [[ToTableViewController alloc] init];
UIView *toView = [[UIView alloc] initWithFrame:CGRectMake(10,10,250,200)];
//toView.backgroundColor = [UIColor redColor];
UITableView *toTableView = [[UITableView alloc] initWithFrame:CGRectMake(10,10,220,180) style:UITableViewStylePlain];

[toTableView setDelegate:toController];
[toTableView setDataSource:toController];

[toView addSubview:toTableView];

[self.view addSubview:toView];

[toTableView reloadData];

I want the ToTableViewController to be the delegate and datasource for this new tableview (toTableView).

The problem is that my ToTableViewController cellForRowAtIndexPath method is not being called. In fact, none of the delegate methods are being called.

Any feedback would be appreciated.

Tim

Answer 1

I am pretty sure your issue is that the toController is being released too early. Using ARC (I assume you are too), I played around with it following what you are trying todo. And I got the same result where the delegate methods appeared NOT to get called. What solved it was to NOT use a local variable for the toController . Instead declare it as a member to the MasterViewController class like

@property (strong, nonatomic) ToTableViewController *toController; 

then use the variable name _toController to refer to it in the code.

EDIT: just to be clear in my first test I had ToTableViewController inherit from a UITableViewController. Since as such I really didn't need that added UITableView you are creating and attaching the delegates too (you could just use the _toController.view directly) SO on this second test I created a ToTableViewController from scratch inheriting from the delegate protocols where the separate UITableView becomes necessary. Just for completeness here is the code that works:

ToTableViewController.h

#import <Foundation/Foundation.h>

@interface ToTableViewController : NSObject <UITableViewDelegate, UITableViewDataSource>

@end

ToTableViewController.m

#import "ToTableViewController.h"

@implementation ToTableViewController

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return 13;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }

    NSString *str1 = @"Row #";
    cell.textLabel.text = [str1 stringByAppendingFormat:@"%d", indexPath.row+1];

    return cell;
}

@end

MasterViewController.m (I declare the toController in the .m file as shown but could do so the .h file instead...)

#import "MasterViewController.h"
#import "ToTableViewController.h"

@interface MasterViewController ()

@property (strong, nonatomic) ToTableViewController *toController;

@end

@implementation MasterViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    _toController = [[ToTableViewController alloc] init];
    UIView *toView = [[UIView alloc] initWithFrame:CGRectMake(10,10,250,200)];
    toView.backgroundColor = [UIColor redColor];

    UITableView *toTableView = [[UITableView alloc] initWithFrame:CGRectMake(10,10,220,180) style:UITableViewStylePlain];

    [toTableView setDelegate:_toController];
    [toTableView setDataSource:_toController];

    [toView addSubview:toTableView];

    [self.view addSubview:toView];
}

@end