Whats wrong with my code,The datasource methods are not called - ios

Question

My code is:
- (instancetype)init {
self = [super initWithNibName:nil bundle:nil];
if (self) {
_tableView = [[UITableView alloc] initWithFrame:CGRectMake(0, 20, self.view.frame.size.width, self.view.frame.size.height - 20)
style:UITableViewStylePlain];
for (int i = 0; i < 10; i++) {
[[LHItemSharedStore sharedStore] createItem];
}
}
return self;
}
- (instancetype)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
return [self init];
}
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[self.tableView reloadData];
}
- (void)viewDidLoad {
[super viewDidLoad];
self.tableView.delegate = self;
self.tableView.dataSource = self;
[self.view addSubview:self.tableView];
[self.tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:#"UITableViewCell"];
}
-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{
return 1;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
return [[[LHItemSharedStore sharedStore] items]count];
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"UITableViewCell" forIndexPath:indexPath];
cell.textLabel.text = #"test";
return cell;
}
As the code show, the datasource methods are not called. but when I put
[self.view addSubView:self.tableView];
In viewWillAppear, the methods can be called correctly, also works when I change [self.view addSubView:self.tableView]; to self.view = self.tableView;

Answer 1

The problem with your code is, that init is probably called after viewDidLoad , thus your table view is still nil when your setting the delegates.

Answer 2

problem solved!
seems that i use self.view.fram in my init method, then loadview is called, then call viewDidLoad, in viewDidLoad the init process of _tableView is not end, so _tableView is nil. if I set self.view = self.tableView in viewDidLoad, it will be called util self.tableView is not nil.
benifit i get it is that put view init into viewDidLoad.