cellForRowAtIndexPath not get called - ios

Question

I understand that many people have asked about this on stack. However, None of these can solve my problem. I try to build a tableview programmatically and cellForRowAtIndexPath is not called. But when I drag a tableview in storyboard, everything is fine. Here is the related code.
This is the code in viewDidLoad
- (void)viewDidLoad
{
[self.navigationController.navigationBar setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:[UIColor whiteColor],NSForegroundColorAttributeName,nil]];
self.navigationController.navigationBar.tintColor=[UIColor whiteColor];
self.navigationItem.title = #"发布失物招领启示";
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]
initWithTarget:self
action:#selector(dismissKeyboard)];
[self.view addGestureRecognizer:tap];
[tap setCancelsTouchesInView:NO];
self.itemDetails = #"请输入详情";
self.view.translatesAutoresizingMaskIntoConstraints = NO;
self.tableView = ({
UITableView *tableView = [[UITableView alloc] initWithFrame:CGRectZero style:UITableViewStyleGrouped];
tableView.dataSource = self;
tableView.delegate = self;
tableView.translatesAutoresizingMaskIntoConstraints = NO;
[tableView reloadData];
tableView;
});
[self.tableView registerNib:[UINib nibWithNibName:campusCellIdentifier bundle:nil] forCellReuseIdentifier:campusCellIdentifier];
[self.tableView registerNib:[UINib nibWithNibName:imageCellIdentifier bundle:nil] forCellReuseIdentifier:imageCellIdentifier];
[self.tableView registerNib:[UINib nibWithNibName:textFieldCellIdentifier bundle:nil] forCellReuseIdentifier:textFieldCellIdentifier];
UIVisualEffectView *effectView = [[UIVisualEffectView alloc] initWithEffect:[UIBlurEffect effectWithStyle:UIBlurEffectStyleExtraLight]];
effectView.frame = self.view.bounds;
[self.view addSubview:effectView];
self.postButton = [[AYVibrantButton alloc] initWithFrame:CGRectZero style:AYVibrantButtonStyleFill];
self.postButton.vibrancyEffect = nil;
self.postButton.text = #"发布";
self.postButton.font = [UIFont systemFontOfSize:18.0];
self.postButton.backgroundColor = [UIColor BBTAppGlobalBlue];
self.postButton.translatesAutoresizingMaskIntoConstraints = NO;
[effectView.contentView addSubview:self.postButton];
[self.view addSubview:self.tableView];
//Set up constraints
CGFloat verticalInnerSpacing = 10.0f;
CGFloat buttonHeight = 50.0f;
CGFloat tabBatHeight = self.tabBarController.tabBar.frame.size.height;
CGFloat navigationBarHeight = self.navigationController.navigationBar.frame.size.height;
[self.tableView mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.equalTo(self.view.mas_top).offset(navigationBarHeight + 20);
make.bottom.equalTo(self.view.mas_bottom).offset(-tabBatHeight - 2*verticalInnerSpacing - buttonHeight);
make.centerX.equalTo(self.view.mas_centerX);
make.width.equalTo(self.view.mas_width);
}];
[self.postButton mas_makeConstraints:^(MASConstraintMaker *make){
make.bottom.equalTo(self.view.mas_bottom).offset(-tabBatHeight - verticalInnerSpacing);
make.height.equalTo(#(buttonHeight));
make.width.equalTo(self.view.mas_width).multipliedBy(0.55);
make.centerX.equalTo(self.view.mas_centerX);
}];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 3;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 3;
}
And the ones in the protocol.
Thanks for help!

Answer 1

Remove
self.view.translatesAutoresizingMaskIntoConstraints = NO;
From your viewDidLoad, as, in general, the system handles the setting of constraints for your view controller's view. The mechanism by which it does this is the autoresizing mask. When self.view.translatesAutoresizingMaskIntoConstraints = NO the system expects constraints to be provided for it, but no constraints have been added, I'm not sure if there's a defined behavior for this instance, but it's best to avoid it by allowing the system handle the size and position of self.view.

Answer 2

As others have said, if you don't add your table view as a subview of the view controller's content view then it won't try to draw itself and none of the delegate/data source methods will ever be called.
Next point: Where is the "related code" from? What method, and where in that method?
Next point:
What is with this syntax?
self.tableView = ({
UITableView *tableView = [[UITableView alloc] initWithFrame:CGRectZero style:UITableViewStyleGrouped];
tableView.dataSource = self;
tableView.delegate = self;
tableView.translatesAutoresizingMaskIntoConstraints = NO;
tableView;
});
Where have you seen that syntax in use in Objective-C code? I have never seen that coding style, and I've been doing Objective-C intensively since about 2007. I gather that the braces denote a scope, and since the last thing in the scope is the expression tableView;, the whole scope evaluates to that variable? Ugh.

Answer 3

You Have To set datasource and delegate of UItableView to your own class.....Other wise your table view will not able to get data from your class variables.....
Follow this link to read about data source and delegation
https://developer.apple.com/library/ios/documentation/General/Conceptual/CocoaEncyclopedia/DelegatesandDataSources/DelegatesandDataSources.html