Present a default view instead of tableview if datasource is empty - iphone

Question

The iOS app I'm currently working on is tabbar-based, and one of the tab is a UITableViewController.
The thing is, when I open this tab with an empty datasource (for whatever reason), I'd like to bring another view, with some kind of message/image, instead of the blank view I get with the tableviewcontroller.
I tried something like that :
- (void)viewWillAppear:(BOOL)animated {
if ([myData count] == 0) {
if (!emptyView) {
emptyView = [[UIView alloc] initWithFrame:self.view.frame];
UILabel *emptyMsg = [[UILabel alloc] initWithFrame:CGRectMake(0, self.view.frame.size.height / 2, self.view.frame.size.width, 20)];
emptyMsg.text = #"This is Empty !";
emptyMsg.textAlignment = UITextAlignmentCenter;
[emptyView addSubview:emptyMsg];
}
[self.view insertSubview:emptyView atIndex:0];
}
else {
if (emptyView != nil) { [emptyView removeFromSuperview]; emptyView = nil; }
[self.tableView reloadData];
[super viewWillAppear:animated];
}
}
With emptyView defined as an iVar in the view controller.
But It doesn't work as expected, and I can't find the reason :/
Could any of you give it a look and give me the proper way to do this kind of behavior ?
Thanks,

Answer 1

I solved this problem by adding a UIView in the tableview header with a frame size equal to tableview size and disallowing user interaction on the tableview:
UIView *emptyView = [[UIView alloc] initWithFrame:self.tableView.frame];
/* Customize your view here or load it from a NIB */
self.tableView.tableHeaderView = emptyView;
self.tableView.userInteractionEnabled = NO;
When you have data you just remove the header and reenable user interaction:
self.tableView.tableHeaderView = nil;
self.tableView.userInteractionEnabled = YES;

Answer 2

UITableViewController doesn't allow you to add subviews to it's view (the tableView).
You should make a UIViewController and add the UITableView yourself with your optional emptyView.
Don't forget to set the dataSource and the delegate!
Update : I've made a subclass of UIViewController to avoid mimics UITableViewController every time.
.h
//
// GCTableViewController.h
// GCLibrary
//
// Created by Guillaume Campagna on 10-06-17.
// Copyright 2010 LittleKiwi. All rights reserved.
//
#import <UIKit/UIKit.h>
//Subclass of UIViewController that mimicks the UITableViewController except that the tableView is a subview of self.view and allow change of the frame of the tableView
#interface GCTableViewController : UIViewController <UITableViewDelegate, UITableViewDataSource>
#property (nonatomic, readonly) UITableView *tableView;
- (id) initWithStyle:(UITableViewStyle)style;
//Subclass if you want to change the type of tableView. The tableView will be automatically placed later
- (UITableView*) tableViewWithStyle:(UITableViewStyle) style;
#end
.m
//
// GCTableViewController.m
// GCLibrary
//
// Created by Guillaume Campagna on 10-06-17.
// Copyright 2010 LittleKiwi. All rights reserved.
//
#import "GCTableViewController.h"
#implementation GCTableViewController
#synthesize tableView;
- (id) initWithStyle:(UITableViewStyle) style {
if (self = [super initWithNibName:nil bundle:nil]) {
tableView = [[self tableViewWithStyle:style] retain];
self.tableView.delegate = self;
self.tableView.dataSource = self;
}
return self;
}
- (void)viewDidLoad {
[super viewDidLoad];
[self.view addSubview:self.tableView];
self.tableView.frame = self.view.bounds;
self.tableView.autoresizingMask = (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight);
}
- (void) viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[self.tableView deselectRowAtIndexPath:[self.tableView indexPathForSelectedRow] animated:YES];
}
#pragma mark TableView methods
- (NSInteger) numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
- (NSInteger) tableView:(UITableView *)table numberOfRowsInSection:(NSInteger)section {
return 0;
}
- (UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
return nil;
}
#pragma mark Getter
- (UITableView *) tableViewWithStyle:(UITableViewStyle)style {
return [[[UITableView alloc] initWithFrame:CGRectZero style:style] autorelease];
}
- (void)dealloc {
[tableView release];
tableView = nil;
[super dealloc];
}
#end

Answer 3

You could perhaps try setting the number of rows to zero. Then inserting the no results view as the header view.